Cisco Catalyst 2975 Software Configuration Manual

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Catalyst 2975 Switch Software Configuration Guide

Cisco IOS Release 12.2(55)SE August 2010

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Text Part Number: OL-19720-02

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THE SPECIFICATIONS AND INFORMATION REGARDING THE PRODUCTS IN THIS MANUAL ARE SUBJECT TO CHANGE WITHOUT NOTICE. ALL STATEMENTS, INFORMATION, AND RECOMMENDATIONS IN THIS MANUAL ARE BELIEVED TO BE ACCURATE BUT ARE PRESENTED WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED. USERS MUST TAKE FULL RESPONSIBILITY FOR THEIR APPLICATION OF ANY PRODUCTS.

THE SOFTWARE LICENSE AND LIMITED WARRANTY FOR THE ACCOMPANYING PRODUCT ARE SET FORTH IN THE INFORMATION PACKET THAT SHIPPED WITH THE PRODUCT AND ARE INCORPORATED HEREIN BY THIS REFERENCE. IF YOU ARE UNABLE TO LOCATE THE SOFTWARE LICENSE OR LIMITED WARRANTY, CONTACT YOUR CISCO REPRESENTATIVE FOR A COPY.

The Cisco implementation of TCP header compression is an adaptation of a program developed by the University of California, Berkeley (UCB) as part of UCB’s public domain version of the UNIX operating system. All rights reserved. Copyright © 1981, Regents of the University of California.

NOTWITHSTANDING ANY OTHER WARRANTY HEREIN, ALL DOCUMENT FILES AND SOFTWARE OF THESE SUPPLIERS ARE PROVIDED “AS IS” WITH ALL FAULTS. CISCO AND THE ABOVE-NAMED SUPPLIERS DISCLAIM ALL WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, THOSE OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OR ARISING FROM A COURSE OF DEALING, USAGE, OR TRADE PRACTICE.

IN NO EVENT SHALL CISCO OR ITS SUPPLIERS BE LIABLE FOR ANY INDIRECT, SPECIAL, CONSEQUENTIAL, OR INCIDENTAL DAMAGES, INCLUDING, WITHOUT LIMITATION, LOST PROFITS OR LOSS OR DAMAGE TO DATA ARISING OUT OF THE USE OR INABILITY TO USE THIS MANUAL, EVEN IF CISCO OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

Cisco and the Cisco Logo are trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and other countries. A listing of Cisco's trademarks can be found at

www.cisco.com/go/trademarks. Third party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership

relationship between Cisco and any other company. (1005R)

Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.

Catalyst 2975 Switch Software Configuration Guide

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Preface xxxv

Audience xxxv

Purpose xxxv

Conventions xxxvi

Related Publications xxxvi

Obtaining Documentation, Obtaining Support, and Security Guidelines xxxvii

CHAPTER

1 Overview 1-1

Features 1-1

Ease-of-Deployment and Ease-of-Use Features 1-2 Performance Features 1-3 Management Options 1-5 Manageability Features 1-5 Availability and Redundancy Features 1-7 VLAN Features 1-8 Security Features 1-8 QoS and CoS Features 1-11 Layer 3 Features 1-12 Power over Ethernet Features 1-12 Monitoring Features 1-12

Default Settings After Initial Switch Configuration 1-13

Network Configuration Examples 1-15

Design Concepts for Using the Switch 1-15 Small to Medium-Sized Network Using Catalyst 2975 Switches 1-19 Long-Distance, High-Bandwidth Transport Configuration 1-20

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Where to Go Next 1-21

2 Using the Command-Line Interface 2-1

Understanding Command Modes 2-1

Understanding the Help System 2-3

Understanding Abbreviated Commands 2-4

Understanding no and default Forms of Commands 2-4

Understanding CLI Error Messages 2-5

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Contents

Using Configuration Logging 2-5

Using Command History 2-6

Changing the Command History Buffer Size 2-6 Recalling Commands 2-6 Disabling the Command History Feature 2-7

Using Editing Features 2-7

Enabling and Disabling Editing Features 2-7 Editing Commands through Keystrokes 2-8 Editing Command Lines that Wrap 2-9

Searching and Filtering Output of show and more Commands 2-10

Accessing the CLI 2-10

Accessing the CLI through a Console Connection or through Telnet 2-10

CHAPTER

3 Assigning the Switch IP Address and Default Gateway 3-1

Understanding the Boot Process 3-2

Assigning Switch Information 3-3

Default Switch Information 3-3 Understanding DHCP-Based Autoconfiguration 3-4

DHCP Client Request Process 3-4

Understanding DHCP-based Autoconfiguration and Image Update 3-5

DHCP Autoconfiguration 3-5 DHCP Auto-Image Update 3-6 Limitations and Restrictions 3-6

Configuring DHCP-Based Autoconfiguration 3-7

DHCP Server Configuration Guidelines 3-7 Configuring the TFTP Server 3-8 Configuring the DNS 3-8 Configuring the Relay Device 3-9 Obtaining Configuration Files 3-9 Example Configuration 3-10

Configuring the DHCP Auto Configuration and Image Update Features 3-12

Configuring DHCP Autoconfiguration (Only Configuration File) 3-12 Configuring DHCP Auto-Image Update (Configuration File and Image) 3-13 Configuring the Client 3-14

Manually Assigning IP Information 3-15

Checking and Saving the Running Configuration 3-16

Configuring the NVRAM Buffer Size 3-17

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Modifying the Startup Configuration 3-18

Default Boot Configuration 3-18 Automatically Downloading a Configuration File 3-18 Specifying the Filename to Read and Write the System Configuration 3-19 Booting Manually 3-19 Booting a Specific Software Image 3-20 Controlling Environment Variables 3-21

Scheduling a Reload of the Software Image 3-23

Configuring a Scheduled Reload 3-23 Displaying Scheduled Reload Information 3-24

Contents

CHAPTER

4 Configuring Cisco IOS Configuration Engine 4-1

Understanding Cisco Configuration Engine Software 4-1

Configuration Service 4-2 Event Service 4-3

NameSpace Mapper 4-3

What You Should Know About the CNS IDs and Device Hostnames 4-3

ConfigID 4-3 DeviceID 4-4 Hostname and DeviceID 4-4 Using Hostname, DeviceID, and ConfigID 4-4

Understanding Cisco IOS Agents 4-5

Initial Configuration 4-5 Incremental (Partial) Configuration 4-6 Synchronized Configuration 4-6

Configuring Cisco IOS Agents 4-6

Enabling Automated CNS Configuration 4-6 Enabling the CNS Event Agent 4-7 Enabling the Cisco IOS CNS Agent 4-9

Enabling an Initial Configuration 4-9 Enabling a Partial Configuration 4-12

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Displaying CNS Configuration 4-13

5 Clustering Switches 5-1

Understanding Switch Clusters 5-1

Cluster Command Switch Characteristics 5-3 Standby Cluster Command Switch Characteristics 5-3 Candidate Switch and Cluster Member Switch Characteristics 5-4

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Contents

Planning a Switch Cluster 5-5

Automatic Discovery of Cluster Candidates and Members 5-5

Discovery Through CDP Hops 5-5 Discovery Through Non-CDP-Capable and Noncluster-Capable Devices 5-7 Discovery Through Different VLANs 5-7 Discovery Through Different Management VLANs 5-8 Discovery of Newly Installed Switches 5-9

HSRP and Standby Cluster Command Switches 5-10

Virtual IP Addresses 5-11 Other Considerations for Cluster Standby Groups 5-11

Automatic Recovery of Cluster Configuration 5-12 IP Addresses 5-13 Hostnames 5-13 Passwords 5-14 SNMP Community Strings 5-14 Switch Clusters and Switch Stacks 5-14 TACACS+ and RADIUS 5-16 LRE Profiles 5-16

CHAPTER

Using the CLI to Manage Switch Clusters 5-16

Using SNMP to Manage Switch Clusters 5-17

6 Managing Switch Stacks 6-1

Understanding Stacks 6-1

Stack Membership 6-3 Master Election 6-4 Stack MAC Address 6-5 Member Numbers 6-6 Member Priority Values 6-6 Stack Offline Configuration 6-7

Effects of Adding a Provisioned Switch to a Stack 6-7

Effects of Replacing a Provisioned Switch in a Stack 6-9

Effects of Removing a Provisioned Switch from a Stack 6-9 Stack Software Compatibility Recommendations 6-9 Stack Protocol Version Compatibility 6-9 Major Version Number Incompatibility Among Switches 6-9 Minor Version Number Incompatibility Among Switches 6-9

Understanding Auto-Upgrade and Auto-Advise 6-10

Auto-Upgrade and Auto-Advise Example Messages 6-11 Incompatible Software and Member Image Upgrades 6-13

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Stack Configuration Files 6-13 Additional Considerations for System-Wide Configuration on Switch Stacks 6-13 Stack Management Connectivity 6-14

Stack Through an IP Address 6-14 Stack Through an SSH Session 6-14 Stack Through Console Ports 6-15 Specific Members 6-15

Stack Configuration Scenarios 6-15

Configuring the Switch Stack 6-17

Default Switch Stack Configuration 6-17 Enabling Persistent MAC Address 6-17 Assigning Stack Member Information 6-19

Assigning a Member Number 6-19 Setting the Member Priority Value 6-20 Provisioning a New Member for a Stack 6-20

Changing the Stack Membership 6-21

Contents

CHAPTER

Accessing the CLI of a Specific Member 6-22

Displaying Stack Information 6-22

Troubleshooting Stacks 6-23

Manually Disabling a Stack Port 6-23 Re-Enabling a Stack Port While Another Member Starts 6-23 Understanding the show switch stack-ports summary Output 6-24 Identifying Loopback Problems 6-25

Software Loopback 6-25 Software Loopback Example: No Connected Stack Cable 6-26 Software Loopback Examples: Connected Stack Cables 6-26 Hardware Loopback 6-27 Hardware Loopback Example: LINK OK event 6-27

Hardware Loop Example: LINK NOT OK Event 6-28 Finding a Disconnected StackWiseStackCable 6-28 Fixing a Bad Connection Between Stack Ports 6-29

7 Administering the Switch 7-1

Managing the System Time and Date 7-1

Understanding the System Clock 7-1 Understanding Network Time Protocol 7-2

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Contents

Configuring NTP 7-4

Default NTP Configuration 7-4 Configuring NTP Authentication 7-5 Configuring NTP Associations 7-6 Configuring NTP Broadcast Service 7-7 Configuring NTP Access Restrictions 7-8 Configuring the Source IP Address for NTP Packets 7-10 Displaying the NTP Configuration 7-11

Configuring Time and Date Manually 7-11

Setting the System Clock 7-11 Displaying the Time and Date Configuration 7-12 Configuring the Time Zone 7-12 Configuring Summer Time (Daylight Saving Time) 7-13

Configuring a System Name and Prompt 7-14

Default System Name and Prompt Configuration 7-15 Configuring a System Name 7-15 Understanding DNS 7-15

Default DNS Configuration 7-16 Setting Up DNS 7-16 Displaying the DNS Configuration 7-17

Creating a Banner 7-17

Default Banner Configuration 7-17 Configuring a Message-of-the-Day Login Banner 7-18 Configuring a Login Banner 7-19

Managing the MAC Address Table 7-19

Building the Address Table 7-20 MAC Addresses and VLANs 7-20 MAC Addresses and Switch Stacks 7-21 Default MAC Address Table Configuration 7-21 Changing the Address Aging Time 7-21 Removing Dynamic Address Entries 7-22 Configuring MAC Address Change Notification Traps 7-22 Configuring MAC Address Move Notification Traps 7-24 Configuring MAC Threshold Notification Traps 7-25 Adding and Removing Static Address Entries 7-26 Configuring Unicast MAC Address Filtering 7-27 Disabling MAC Address Learning on a VLAN 7-28 Displaying Address Table Entries 7-30

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Managing the ARP Table 7-30

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Contents

CHAPTER

8 Configuring SDM Templates 8-1

Understanding the SDM Templates 8-1

SDM Templates and Switch Stacks 8-2

Configuring the Switch SDM Template 8-3

Default SDM Template 8-3 SDM Template Configuration Guidelines 8-3 Setting the SDM Template 8-4

.Displaying the SDM Templates 8-4

9 Configuring Switch-Based Authentication 9-1

Preventing Unauthorized Access to Your Switch 9-1

Protecting Access to Privileged EXEC Commands 9-2

Default Password and Privilege Level Configuration 9-3 Setting or Changing a Static Enable Password 9-3 Protecting Enable and Enable Secret Passwords with Encryption 9-4 Disabling Password Recovery 9-5 Setting a Telnet Password for a Terminal Line 9-6 Configuring Username and Password Pairs 9-7 Configuring Multiple Privilege Levels 9-8

Setting the Privilege Level for a Command 9-8

Changing the Default Privilege Level for Lines 9-9

Logging into and Exiting a Privilege Level 9-10

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Controlling Switch Access with TACACS+ 9-10

Understanding TACACS+ 9-10 TACACS+ Operation 9-12 Configuring TACACS+ 9-13

Default TACACS+ Configuration 9-13

Identifying the TACACS+ Server Host and Setting the Authentication Key 9-13

Configuring TACACS+ Login Authentication 9-14

Configuring TACACS+ Authorization for Privileged EXEC Access and Network Services 9-16

Starting TACACS+ Accounting 9-17

Establishing a Session with a Router if the AAA Server is Unreachable 9-18 Displaying the TACACS+ Configuration 9-18

Controlling Switch Access with RADIUS 9-18

Understanding RADIUS 9-18 RADIUS Operation 9-20 RADIUS Change of Authorization 9-20

Overview 9-20

Change-of-Authorization Requests 9-21

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Contents

CoA Request Response Code 9-22 CoA Request Commands 9-23 Stacking Guidelines for Session Termination 9-26

Configuring RADIUS 9-27

Default RADIUS Configuration 9-27 Identifying the RADIUS Server Host 9-28 Configuring RADIUS Login Authentication 9-30 Defining AAA Server Groups 9-32 Configuring RADIUS Authorization for User Privileged Access and Network Services 9-34 Starting RADIUS Accounting 9-35 Establishing a Session with a Router if the AAA Server is Unreachable 9-36 Configuring Settings for All RADIUS Servers 9-36 Configuring the Switch to Use Vendor-Specific RADIUS Attributes 9-36 Configuring the Switch for Vendor-Proprietary RADIUS Server Communication 9-38 Configuring CoA on the Switch 9-39 Monitoring and Troubleshooting CoA Functionality 9-40 Configuring RADIUS Server Load Balancing 9-40

Displaying the RADIUS Configuration 9-40

Configuring the Switch for Local Authentication and Authorization 9-40

Configuring the Switch for Secure Shell 9-41

Understanding SSH 9-42

SSH Servers, Integrated Clients, and Supported Versions 9-42 Limitations 9-43

Configuring SSH 9-43

Configuration Guidelines 9-43 Setting Up the Switch to Run SSH 9-43 Configuring the SSH Server 9-44

Displaying the SSH Configuration and Status 9-45

Configuring the Switch for Secure Socket Layer HTTP 9-46

Understanding Secure HTTP Servers and Clients 9-46

Certificate Authority Trustpoints 9-46 CipherSuites 9-48

Configuring Secure HTTP Servers and Clients 9-48

Default SSL Configuration 9-48 SSL Configuration Guidelines 9-49 Configuring a CA Trustpoint 9-49 Configuring the Secure HTTP Server 9-50 Configuring the Secure HTTP Client 9-51

Displaying Secure HTTP Server and Client Status 9-52

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Configuring the Switch for Secure Copy Protocol 9-52

Information About Secure Copy 9-53

Contents

CHAPTER

10 Configuring IEEE 802.1x Port-Based Authentication 10-1

Understanding IEEE 802.1x Port-Based Authentication 10-1

Device Roles 10-2 Authentication Process 10-3 Authentication Initiation and Message Exchange 10-5 Authentication Manager 10-7

Port-Based Authentication Methods 10-7

Per-User ACLs and Filter-Ids 10-8

Authentication Manager CLI Commands 10-9 Ports in Authorized and Unauthorized States 10-10

802.1x Authentication and Switch Stacks 10-11

802.1x Host Mode 10-12 Multidomain Authentication 10-12

802.1x Multiple Authentication Mode 10-13 MAC Move 10-14 MAC Replace 10-15

802.1x Accounting 10-15

802.1x Accounting Attribute-Value Pairs 10-16

802.1x Readiness Check 10-17

802.1x Authentication with VLAN Assignment 10-17

802.1x Authentication with Downloadable ACLs and Redirect URLs 10-18

Cisco Secure ACS and Attribute-Value Pairs for the Redirect URL 10-20

Cisco Secure ACS and Attribute-Value Pairs for Downloadable ACLs 10-20

VLAN ID-based MAC Authentication 10-20

802.1x Authentication with Guest VLAN 10-21

802.1x Authentication with Restricted VLAN 10-22

802.1x Authentication with Inaccessible Authentication Bypass 10-23

Support on Multiple-Authentication Ports 10-23

Authentication Results 10-23

Feature Interactions 10-24

802.1x Authentication with Voice VLAN Ports 10-24

802.1x Authentication with Port Security 10-25

802.1x Authentication with Wake-on-LAN 10-26

802.1x Authentication with MAC Authentication Bypass 10-26

802.1x User Distribution 10-28

802.1x User Distribution Configuration Guidelines 10-28

Network Admission Control Layer 2 802.1x Validation 10-29

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Contents

Flexible Authentication Ordering 10-29 Open1x Authentication 10-29 Using Voice Aware 802.1x Security 10-30

802.1x Supplicant and Authenticator Switches with Network Edge Access Topology (NEAT) 10-30 Guidelines 10-31

Using IEEE 802.1x Authentication with ACLs and the RADIUS Filter-Id Attribute 10-31 Common Session ID 10-32

Configuring 802.1x Authentication 10-32

Default 802.1x Authentication Configuration 10-33

802.1x Authentication Configuration Guidelines 10-35

802.1x Authentication 10-35 VLAN Assignment, Guest VLAN, Restricted VLAN, and Inaccessible Authentication

Bypass 10-36 MAC Authentication Bypass 10-36 Maximum Number of Allowed Devices Per Port 10-37

Configuring 802.1x Readiness Check 10-37 Configuring Voice Aware 802.1x Security 10-38 Configuring 802.1x Violation Modes 10-39 Configuring 802.1x Authentication 10-40 Configuring the Switch-to-RADIUS-Server Communication 10-41 Configuring the Host Mode 10-43 Configuring Periodic Re-Authentication 10-44 Manually Re-Authenticating a Client Connected to a Port 10-45 Changing the Quiet Period 10-45 Changing the Switch-to-Client Retransmission Time 10-46 Setting the Switch-to-Client Frame-Retransmission Number 10-47 Setting the Re-Authentication Number 10-47 Enabling MAC Move 10-48 Enabling MAC Replace 10-48 Configuring 802.1x Accounting 10-49 Configuring a Guest VLAN 10-50 Configuring a Restricted VLAN 10-51 Configuring the Inaccessible Authentication Bypass Feature 10-53 Configuring 802.1x Authentication with WoL 10-56 Configuring MAC Authentication Bypass 10-57 Configuring 802.1x User Distribution 10-58 Configuring NAC Layer 2 802.1x Validation 10-59 Configuring an Authenticator and a Supplicant Switch with NEAT 10-60

Configuring NEAT with Auto Smartports Macros 10-61

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Configuring 802.1x Authentication with Downloadable ACLs and Redirect URLs 10-61

Configuring Downloadable ACLs 10-62

Configuring a Downloadable Policy 10-62 Configuring VLAN ID-based MAC Authentication 10-64 Configuring Flexible Authentication Ordering 10-64 Configuring Open1x 10-65 Disabling 802.1x Authentication on the Port 10-65 Resetting the 802.1x Authentication Configuration to the Default Values 10-66

Displaying 802.1x Statistics and Status 10-67

Contents

CHAPTER

11 Configuring Web-Based Authentication 11-1

Understanding Web-Based Authentication 11-1

Device Roles 11-2 Host Detection 11-2 Session Creation 11-3 Authentication Process 11-3 Local Web Authentication Banner 11-4 Web Authentication Customizable Web Pages 11-6

Guidelines 11-6 Web-based Authentication Interactions with Other Features 11-7

Port Security 11-7

LAN Port IP 11-8

Gateway IP 11-8

ACLs 11-8

Context-Based Access Control 11-8

802.1x Authentication 11-8

EtherChannel 11-8

Configuring Web-Based Authentication 11-9

Default Web-Based Authentication Configuration 11-9 Web-Based Authentication Configuration Guidelines and Restrictions 11-9 Web-Based Authentication Configuration Task List 11-10 Configuring the Authentication Rule and Interfaces 11-10 Configuring AAA Authentication 11-11 Configuring Switch-to-RADIUS-Server Communication 11-11 Configuring the HTTP Server 11-13

Customizing the Authentication Proxy Web Pages 11-13

Specifying a Redirection URL for Successful Login 11-15 Configuring an AAA Fail Policy 11-15 Configuring the Web-Based Authentication Parameters 11-16

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Contents

Configuring a Web Authentication Local Banner 11-16 Removing Web-Based Authentication Cache Entries 11-17

Displaying Web-Based Authentication Status 11-17

CHAPTER

12 Configuring Interface Characteristics 12-1

Understanding Interface Types 12-1

Port-Based VLANs 12-2 Switch Ports 12-2

Access Ports 12-2

Trunk Ports 12-3 Switch Virtual Interfaces 12-3 EtherChannel Port Groups 12-4 Dual-Purpose Uplink Ports 12-4 Power over Ethernet Ports 12-4

Supported Protocols and Standards 12-5

Powered-Device Detection and Initial Power Allocation 12-5

Power Management Modes 12-7

Power Monitoring and Power Policing 12-8 Connecting Interfaces 12-10

Using Interface Configuration Mode 12-11

Procedures for Configuring Interfaces 12-12 Configuring a Range of Interfaces 12-12 Configuring and Using Interface Range Macros 12-14

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Configuring Ethernet Interfaces 12-16

Default Ethernet Interface Configuration 12-16 Setting the Type of a Dual-Purpose Uplink Port 12-17 Configuring Interface Speed and Duplex Mode 12-19

Speed and Duplex Configuration Guidelines 12-19

Setting the Interface Speed and Duplex Parameters 12-20 Configuring IEEE 802.3x Flow Control 12-21 Configuring Auto-MDIX on an Interface 12-22 Configuring a Power Management Mode on a PoE Port 12-23 Budgeting Power for Devices Connected to a PoE Port 12-24 Configuring Power Policing 12-26 Adding a Description for an Interface 12-27

Configuring Layer 3 SVIs 12-27

Configuring the System MTU 12-28

Monitoring and Maintaining the Interfaces 12-29

Monitoring Interface Status 12-30

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Clearing and Resetting Interfaces and Counters 12-30 Shutting Down and Restarting the Interface 12-31

Contents

CHAPTER

13 Configuring VLANs 13-1

Understanding VLANs 13-1

Supported VLANs 13-2 VLAN Port Membership Modes 13-3

Configuring Normal-Range VLANs 13-4

Token Ring VLANs 13-5 Normal-Range VLAN Configuration Guidelines 13-5 Configuring Normal-Range VLANs 13-6 Default Ethernet VLAN Configuration 13-6 Creating or Modifying an Ethernet VLAN 13-7 Deleting a VLAN 13-8 Assigning Static-Access Ports to a VLAN 13-9

Configuring Extended-Range VLANs 13-10

Default VLAN Configuration 13-10 Extended-Range VLAN Configuration Guidelines 13-10 Creating an Extended-Range VLAN 13-11

Displaying VLANs 13-12

Configuring VLAN Trunks 13-13

Trunking Overview 13-13

IEEE 802.1Q Configuration Considerations 13-14 Default Layer 2 Ethernet Interface VLAN Configuration 13-14 Configuring an Ethernet Interface as a Trunk Port 13-15

Interaction with Other Features 13-15

Configuring a Trunk Port 13-16

Defining the Allowed VLANs on a Trunk 13-17

Changing the Pruning-Eligible List 13-18

Configuring the Native VLAN for Untagged Traffic 13-19 Configuring Trunk Ports for Load Sharing 13-19

Load Sharing Using STP Port Priorities 13-20

Load Sharing Using STP Path Cost 13-21

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Configuring VMPS 13-23

Understanding VMPS 13-23

Dynamic-Access Port VLAN Membership 13-24 Default VMPS Client Configuration 13-24 VMPS Configuration Guidelines 13-24 Configuring the VMPS Client 13-25

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Entering the IP Address of the VMPS 13-25 Configuring Dynamic-Access Ports on VMPS Clients 13-26 Reconfirming VLAN Memberships 13-26 Changing the Reconfirmation Interval 13-27

Changing the Retry Count 13-27 Monitoring the VMPS 13-28 Troubleshooting Dynamic-Access Port VLAN Membership 13-28 VMPS Configuration Example 13-28

CHAPTER

14 Configuring Voice VLAN 14-1

Understanding Voice VLAN 14-1

Cisco IP Phone Voice Traffic 14-2 Cisco IP Phone Data Traffic 14-3

Configuring Voice VLAN 14-3

Default Voice VLAN Configuration 14-3 Voice VLAN Configuration Guidelines 14-3 Configuring a Port Connected to a Cisco 7960 IP Phone 14-5

Configuring Cisco IP Phone Voice Traffic 14-5

Configuring the Priority of Incoming Data Frames 14-6

Displaying Voice VLAN 14-7

15 Configuring VTP 15-1

Understanding VTP 15-1

The VTP Domain 15-2 VTP Modes 15-3 VTP Advertisements 15-4 VTP Version 2 15-4 VTP Version 3 15-5 VTP Pruning 15-6 VTP and Switch Stacks 15-7

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Configuring VTP 15-8

Default VTP Configuration 15-8 VTP Configuration Guidelines 15-8

Domain Names 15-9

Passwords 15-9

VTP Version 15-10

Configuration Requirements 15-10

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Configuring VTP Mode 15-11

Configuring a VTP Version 3 Password 15-13

Configuring a VTP Version 3 Primary Server 15-13 Enabling the VTP Version 15-14 Enabling VTP Pruning 15-15 Configuring VTP on a Per-Port Basis 15-15 Adding a VTP Client Switch to a VTP Domain 15-16

Monitoring VTP 15-17

Contents

CHAPTER

16 Configuring STP 16-1

Understanding Spanning-Tree Features 16-1

STP Overview 16-2 Spanning-Tree Topology and BPDUs 16-3 Bridge ID, Switch Priority, and Extended System ID 16-5 Spanning-Tree Interface States 16-5

Blocking State 16-7

Listening State 16-7

Learning State 16-7

Forwarding State 16-7

Disabled State 16-8 How a Switch or Port Becomes the Root Switch or Root Port 16-8 Spanning Tree and Redundant Connectivity 16-9 Spanning-Tree Address Management 16-9 Accelerated Aging to Retain Connectivity 16-9 Spanning-Tree Modes and Protocols 16-10 Supported Spanning-Tree Instances 16-10 Spanning-Tree Interoperability and Backward Compatibility 16-11 STP and IEEE 802.1Q Trunks 16-11 Spanning Tree and Switch Stacks 16-12

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Configuring Spanning-Tree Features 16-12

Default Spanning-Tree Configuration 16-13 Spanning-Tree Configuration Guidelines 16-13 Changing the Spanning-Tree Mode. 16-15 Disabling Spanning Tree 16-16 Configuring the Root Switch 16-16 Configuring a Secondary Root Switch 16-18 Configuring Port Priority 16-18 Configuring Path Cost 16-20 Configuring the Switch Priority of a VLAN 16-21

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Contents

Configuring Spanning-Tree Timers 16-22

Configuring the Hello Time 16-22 Configuring the Forwarding-Delay Time for a VLAN 16-23 Configuring the Maximum-Aging Time for a VLAN 16-23 Configuring the Transmit Hold-Count 16-24

Displaying the Spanning-Tree Status 16-24

CHAPTER

17 Configuring MSTP 17-1

Understanding MSTP 17-2

Multiple Spanning-Tree Regions 17-2 IST, CIST, and CST 17-3

Operations Within an MST Region 17-3 Operations Between MST Regions 17-4

IEEE 802.1s Terminology 17-5 Hop Count 17-6 Boundary Ports 17-6 IEEE 802.1s Implementation 17-7

Port Role Naming Change 17-7

Interoperation Between Legacy and Standard Switches 17-7

Detecting Unidirectional Link Failure 17-8 MSTP and Switch Stacks 17-9 Interoperability with IEEE 802.1D STP 17-9

Understanding RSTP 17-9

Port Roles and the Active Topology 17-10 Rapid Convergence 17-11 Synchronization of Port Roles 17-12 Bridge Protocol Data Unit Format and Processing 17-13

Processing Superior BPDU Information 17-14

Processing Inferior BPDU Information 17-14 Topology Changes 17-14

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Configuring MSTP Features 17-15

Default MSTP Configuration 17-16 MSTP Configuration Guidelines 17-16 Specifying the MST Region Configuration and Enabling MSTP 17-17 Configuring the Root Switch 17-19 Configuring a Secondary Root Switch 17-20 Configuring Port Priority 17-21 Configuring Path Cost 17-23 Configuring the Switch Priority 17-24

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Configuring the Hello Time 17-25 Configuring the Forwarding-Delay Time 17-25 Configuring the Maximum-Aging Time 17-26 Configuring the Maximum-Hop Count 17-26 Specifying the Link Type to Ensure Rapid Transitions 17-27 Designating the Neighbor Type 17-27 Restarting the Protocol Migration Process 17-28

Displaying the MST Configuration and Status 17-28

Contents

CHAPTER

18 Configuring Optional Spanning-Tree Features 18-1

Understanding Optional Spanning-Tree Features 18-1

Understanding Port Fast 18-2 Understanding BPDU Guard 18-2 Understanding BPDU Filtering 18-3 Understanding UplinkFast 18-3 Understanding Cross-Stack UplinkFast 18-5

How CSUF Works 18-6

Events that Cause Fast Convergence 18-7 Understanding BackboneFast 18-7 Understanding EtherChannel Guard 18-10 Understanding Root Guard 18-10 Understanding Loop Guard 18-11

Configuring Optional Spanning-Tree Features 18-12

Default Optional Spanning-Tree Configuration 18-12 Optional Spanning-Tree Configuration Guidelines 18-12 Enabling Port Fast 18-13 Enabling BPDU Guard 18-14 Enabling BPDU Filtering 18-15 Enabling UplinkFast for Use with Redundant Links 18-16 Enabling Cross-Stack UplinkFast 18-17 Enabling BackboneFast 18-17 Enabling EtherChannel Guard 18-17 Enabling Root Guard 18-18 Enabling Loop Guard 18-19

CHAPTER

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Displaying the Spanning-Tree Status 18-19

19 Configuring Flex Links and the MAC Address-Table Move Update Feature 19-1

Understanding Flex Links and the MAC Address-Table Move Update 19-1

Flex Links 19-1

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Contents

VLAN Flex Link Load Balancing and Support 19-3 Flex Link Multicast Fast Convergence 19-3

Learning the Other Flex Link Port as the mrouter Port 19-3 Generating IGMP Reports 19-4 Leaking IGMP Reports 19-4 Configuration Examples 19-4

MAC Address-Table Move Update 19-6

Configuring Flex Links and the MAC Address-Table Move Update 19-7

Default Configuration 19-8 Configuration Guidelines 19-8 Configuring Flex Links 19-9 Configuring VLAN Load Balancing on Flex Links 19-11 Configuring the MAC Address-Table Move Update Feature 19-12

Monitoring Flex Links and the MAC Address-Table Move Update 19-14

CHAPTER

20 Configuring DHCP Features and IP Source Guard Features 20-1

Understanding DHCP Snooping 20-1

DHCP Server 20-2 DHCP Relay Agent 20-2 DHCP Snooping 20-2 Option-82 Data Insertion 20-4 DHCP Snooping Binding Database 20-7 DHCP Snooping and Switch Stacks 20-8

Configuring DHCP Snooping 20-9

Default DHCP Snooping Configuration 20-9 DHCP Snooping Configuration Guidelines 20-9 Configuring the DHCP Relay Agent 20-11 Enabling DHCP Snooping and Option 82 20-11 Enabling the DHCP Snooping Binding Database Agent 20-13

Displaying DHCP Snooping Information 20-14

Understanding IP Source Guard 20-15

Source IP Address Filtering 20-15 Source IP and MAC Address Filtering 20-15 IP Source Guard for Static Hosts 20-16

Configuring IP Source Guard 20-17

Default IP Source Guard Configuration 20-17 IP Source Guard Configuration Guidelines 20-17 Enabling IP Source Guard 20-18

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Configuring IP Source Guard for Static Hosts 20-19

Configuring IP Source Guard for Static Hosts on a Layer 2 Access Port 20-19

Displaying IP Source Guard Information 20-22

Understanding DHCP Server Port-Based Address Allocation 20-23

Configuring DHCP Server Port-Based Address Allocation 20-23

Default Port-Based Address Allocation Configuration 20-23 Port-Based Address Allocation Configuration Guidelines 20-23 Enabling DHCP Server Port-Based Address Allocation 20-24

Displaying DHCP Server Port-Based Address Allocation 20-26

Contents

CHAPTER

21 Configuring Dynamic ARP Inspection 21-1

Understanding Dynamic ARP Inspection 21-1

Interface Trust States and Network Security 21-3 Rate Limiting of ARP Packets 21-4 Relative Priority of ARP ACLs and DHCP Snooping Entries 21-4 Logging of Dropped Packets 21-5

Configuring Dynamic ARP Inspection 21-5

Default Dynamic ARP Inspection Configuration 21-5 Dynamic ARP Inspection Configuration Guidelines 21-6 Configuring Dynamic ARP Inspection in DHCP Environments 21-7 Configuring ARP ACLs for Non-DHCP Environments 21-9 Limiting the Rate of Incoming ARP Packets 21-11 Performing Validation Checks 21-12 Configuring the Log Buffer 21-13

Displaying Dynamic ARP Inspection Information 21-15

22 Configuring IGMP Snooping and MVR 22-1

Understanding IGMP Snooping 22-1

IGMP Versions 22-2 Joining a Multicast Group 22-3 Leaving a Multicast Group 22-5 Immediate Leave 22-5 IGMP Configurable-Leave Timer 22-5 IGMP Report Suppression 22-5 IGMP Snooping and Switch Stacks 22-6

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Default IGMP Snooping Configuration 22-7 Enabling or Disabling IGMP Snooping 22-7

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Contents

Setting the Snooping Method 22-8 Configuring a Multicast Router Port 22-9 Configuring a Host Statically to Join a Group 22-10 Enabling IGMP Immediate Leave 22-10 Configuring the IGMP Leave Timer 22-11 Configuring TCN-Related Commands 22-12

Controlling the Multicast Flooding Time After a TCN Event 22-12 Recovering from Flood Mode 22-12

Disabling Multicast Flooding During a TCN Event 22-13 Configuring the IGMP Snooping Querier 22-14 Disabling IGMP Report Suppression 22-15

Displaying IGMP Snooping Information 22-15

Understanding Multicast VLAN Registration 22-17

Using MVR in a Multicast Television Application 22-17

Configuring MVR 22-19

Default MVR Configuration 22-19 MVR Configuration Guidelines and Limitations 22-20 Configuring MVR Global Parameters 22-20 Configuring MVR Interfaces 22-21

CHAPTER

Displaying MVR Information 22-23

Configuring IGMP Filtering and Throttling 22-24

Default IGMP Filtering and Throttling Configuration 22-25 Configuring IGMP Profiles 22-25 Applying IGMP Profiles 22-26 Setting the Maximum Number of IGMP Groups 22-27 Configuring the IGMP Throttling Action 22-28

Displaying IGMP Filtering and Throttling Configuration 22-29

23 Configuring Port-Based Traffic Control 23-1

Configuring Storm Control 23-1

Understanding Storm Control 23-2 Default Storm Control Configuration 23-3 Configuring Storm Control and Threshold Levels 23-3 Configuring Small-Frame Arrival Rate 23-5

Configuring Protected Ports 23-6

Default Protected Port Configuration 23-7 Protected Port Configuration Guidelines 23-7 Configuring a Protected Port 23-7

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Default Port Blocking Configuration 23-8 Blocking Flooded Traffic on an Interface 23-8

Configuring Port Security 23-9

Understanding Port Security 23-9

Secure MAC Addresses 23-9

Security Violations 23-10 Default Port Security Configuration 23-11 Port Security Configuration Guidelines 23-12 Enabling and Configuring Port Security 23-13 Enabling and Configuring Port Security Aging 23-17 Port Security and Switch Stacks 23-18

Displaying Port-Based Traffic Control Settings 23-18

Contents

CHAPTER

24 Configuring CDP 24-1

Understanding CDP 24-1

CDP and Switch Stacks 24-2

Configuring CDP 24-2

Default CDP Configuration 24-2 Configuring the CDP Characteristics 24-3 Disabling and Enabling CDP 24-3 Disabling and Enabling CDP on an Interface 24-4

Monitoring and Maintaining CDP 24-5

25 Configuring LLDP, LLDP-MED, and Wired Location Service 25-1

Understanding LLDP, LLDP-MED, and Wired Location Service 25-1

LLDP 25-1 LLDP-MED 25-2 Wired Location Service 25-3

Configuring LLDP, LLDP-MED, and Wired Location Service 25-5

Default LLDP Configuration 25-5 Configuration Guidelines 25-5 Enabling LLDP 25-6 Configuring LLDP Characteristics 25-7 Configuring LLDP-MED TLVs 25-8 Configuring Network-Policy TLV 25-9 Configuring Location TLV and Wired Location Service 25-10

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Contents

CHAPTER

26 Configuring UDLD 26-1

Understanding UDLD 26-1

Modes of Operation 26-1 Methods to Detect Unidirectional Links 26-2

Configuring UDLD 26-3

Default UDLD Configuration 26-4 Configuration Guidelines 26-4 Enabling UDLD Globally 26-5 Enabling UDLD on an Interface 26-6 Resetting an Interface Disabled by UDLD 26-6

Displaying UDLD Status 26-7

27 Configuring SPAN and RSPAN 27-1

Understanding SPAN and RSPAN 27-1

Local SPAN 27-2 Remote SPAN 27-3 SPAN and RSPAN Concepts and Terminology 27-4

SPAN Sessions 27-4 Monitored Traffic 27-5 Source Ports 27-6 Source VLANs 27-7 VLAN Filtering 27-7 Destination Port 27-8

RSPAN VLAN 27-9 SPAN and RSPAN Interaction with Other Features 27-9 SPAN and RSPAN and Switch Stacks 27-10

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Configuring SPAN and RSPAN 27-10

Default SPAN and RSPAN Configuration 27-11 Configuring Local SPAN 27-11

SPAN Configuration Guidelines 27-11

Creating a Local SPAN Session 27-12

Creating a Local SPAN Session and Configuring Incoming Traffic 27-14

Specifying VLANs to Filter 27-16 Configuring RSPAN 27-17

RSPAN Configuration Guidelines 27-17

Configuring a VLAN as an RSPAN VLAN 27-18

Creating an RSPAN Source Session 27-19

Creating an RSPAN Destination Session 27-20

Creating an RSPAN Destination Session and Configuring Incoming Traffic 27-21

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Specifying VLANs to Filter 27-23

Displaying SPAN and RSPAN Status 27-24

Contents

CHAPTER

28 Configuring RMON 28-1

Understanding RMON 28-2

Configuring RMON 28-3

Default RMON Configuration 28-3 Configuring RMON Alarms and Events 28-3 Collecting Group History Statistics on an Interface 28-5 Collecting Group Ethernet Statistics on an Interface 28-6

Displaying RMON Status 28-7

29 Configuring System Message Logging 29-1

Understanding System Message Logging 29-1

Configuring System Message Logging 29-2

System Log Message Format 29-2 Default System Message Logging Configuration 29-4 Disabling Message Logging 29-4 Setting the Message Display Destination Device 29-5 Synchronizing Log Messages 29-6 Enabling and Disabling Time Stamps on Log Messages 29-8 Enabling and Disabling Sequence Numbers in Log Messages 29-8 Defining the Message Severity Level 29-9 Limiting Syslog Messages Sent to the History Table and to SNMP 29-10 Enabling the Configuration-Change Logger 29-11 Configuring UNIX Syslog Servers 29-12

Logging Messages to a UNIX Syslog Daemon 29-13 Configuring the UNIX System Logging Facility 29-13

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Displaying the Logging Configuration 29-14

30 Configuring SNMP 30-1

Understanding SNMP 30-1

SNMP Versions 30-2 SNMP Manager Functions 30-3 SNMP Agent Functions 30-4 SNMP Community Strings 30-4 Using SNMP to Access MIB Variables 30-4 SNMP Notifications 30-5

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SNMP ifIndex MIB Object Values 30-5

Configuring SNMP 30-6

Default SNMP Configuration 30-6 SNMP Configuration Guidelines 30-7 Disabling the SNMP Agent 30-7 Configuring Community Strings 30-8 Configuring SNMP Groups and Users 30-9 Configuring SNMP Notifications 30-12 Setting the CPU Threshold Notification Types and Values 30-15 Setting the Agent Contact and Location Information 30-16 Limiting TFTP Servers Used Through SNMP 30-16 SNMP Examples 30-17

Displaying SNMP Status 30-18

CHAPTER

31 Configuring Network Security with ACLs 31-1

Understanding ACLs 31-1

Supported ACLs 31-2

Port ACLs 31-3

Router ACLs 31-4 Handling Fragmented and Unfragmented Traffic 31-4 ACLs and Switch Stacks 31-5

Configuring IPv4 ACLs 31-6

Creating Standard and Extended IPv4 ACLs 31-6

Access List Numbers 31-7

Creating a Numbered Standard ACL 31-8

Creating a Numbered Extended ACL 31-9

Resequencing ACEs in an ACL 31-13

Creating Named Standard and Extended ACLs 31-13

Using Time Ranges with ACLs 31-15

Including Comments in ACLs 31-16 Applying an IPv4 ACL to a Terminal Line 31-17 Applying an IPv4 ACL to an Interface 31-18 Hardware and Software Treatment of IP ACLs 31-19 Troubleshooting ACLs 31-19 IPv4 ACL Configuration Examples 31-20

Numbered ACLs 31-21

Extended ACLs 31-21

Named ACLs 31-21

Time Range Applied to an IP ACL 31-21

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Commented IP ACL Entries 31-22

Creating Named MAC Extended ACLs 31-22

Applying a MAC ACL to a Layer 2 Interface 31-23

Displaying IPv4 ACL Configuration 31-25

Contents

CHAPTER

32 Configuring Cisco IOS IP SLAs Operations 32-1

Understanding Cisco IOS IP SLAs 32-1

Using Cisco IOS IP SLAs to Measure Network Performance 32-2 IP SLAs Responder and IP SLAs Control Protocol 32-3 Response Time Computation for IP SLAs 32-4

Configuring IP SLAs Operations 32-5

Default Configuration 32-5 Configuration Guidelines 32-5 Configuring the IP SLAs Responder 32-6

Monitoring IP SLAs Operations 32-6

33 Configuring QoS 33-1

Understanding QoS 33-1

Basic QoS Model 33-4 Classification 33-5

Classification Based on QoS ACLs 33-8 Classification Based on Class Maps and Policy Maps 33-8

Policing and Marking 33-9

Policing on Physical Ports 33-10 Mapping Tables 33-11 Queueing and Scheduling Overview 33-12

Weighted Tail Drop 33-12

SRR Shaping and Sharing 33-13

Queueing and Scheduling on Ingress Queues 33-14

Queueing and Scheduling on Egress Queues 33-16 Packet Modification 33-19

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Configuring Auto-QoS 33-20

Generated Auto-QoS Configuration 33-20

VOIP Device Specifics 33-21

Enhanced Auto-QoS for Video, Trust, and Classification 33-22

Auto-QoS Configuration Migration 33-22

Global Auto-QoS Configuration 33-23

Auto-QoS Generated Configuration For VoIP Devices 33-26

Auto-QoS Generated Configuration For Enhanced Video, Trust, and Classify Devices 33-27

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Contents

Effects of Auto-QoS on the Configuration 33-30 Auto-QoS Configuration Guidelines 33-30

Auto-QoS Enhanced Considerations 33-31 Enabling Auto-QoS 33-31 Troubleshooting Auto QoS Commands 33-32

Displaying Auto-QoS Information 33-32

Configuring Standard QoS 33-33

Default Standard QoS Configuration 33-33

Default Ingress Queue Configuration 33-34

Default Egress Queue Configuration 33-34

Default Mapping Table Configuration 33-35 Standard QoS Configuration Guidelines 33-36

QoS ACL Guidelines 33-36

Policing Guidelines 33-36

General QoS Guidelines 33-37 Enabling QoS Globally 33-37 Configuring Classification Using Port Trust States 33-37

Configuring the Trust State on Ports within the QoS Domain 33-37

Configuring the CoS Value for an Interface 33-39

Configuring a Trusted Boundary to Ensure Port Security 33-40

Enabling DSCP Transparency Mode 33-41

Configuring the DSCP Trust State on a Port Bordering Another QoS Domain 33-42 Configuring a QoS Policy 33-44

Classifying Traffic by Using ACLs 33-45

Classifying Traffic by Using Class Maps 33-48

Classifying, Policing, and Marking Traffic on Physical Ports by Using Policy Maps 33-50

Classifying, Policing, and Marking Traffic by Using Aggregate Policers 33-55 Configuring DSCP Maps 33-57

Configuring the CoS-to-DSCP Map 33-57

Configuring the IP-Precedence-to-DSCP Map 33-58

Configuring the Policed-DSCP Map 33-59

Configuring the DSCP-to-CoS Map 33-60

Configuring the DSCP-to-DSCP-Mutation Map 33-61 Configuring Ingress Queue Characteristics 33-63

Mapping DSCP or CoS Values to an Ingress Queue and Setting WTD Thresholds 33-63

Allocating Buffer Space Between the Ingress Queues 33-65

Allocating Bandwidth Between the Ingress Queues 33-65

Configuring the Ingress Priority Queue 33-66 Configuring Egress Queue Characteristics 33-67

Configuration Guidelines 33-68

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Allocating Buffer Space to and Setting WTD Thresholds for an Egress Queue-Set 33-68 Mapping DSCP or CoS Values to an Egress Queue and to a Threshold ID 33-70 Configuring SRR Shaped Weights on Egress Queues 33-72 Configuring SRR Shared Weights on Egress Queues 33-73 Configuring the Egress Expedite Queue 33-74 Limiting the Bandwidth on an Egress Interface 33-74

Displaying Standard QoS Information 33-75

Contents

CHAPTER

34 Configuring Static IP Unicast Routing 34-1

Understanding IP Routing 34-1

Types of Routing 34-2 IP Routing and Switch Stacks 34-2

Steps for Configuring Routing 34-3

Enabling IP Unicast Routing 34-3

Assigning IP Addresses to SVIs 34-4

Configuring Static Unicast Routes 34-5

Monitoring and Maintaining the IP Network 34-5

35 Configuring IPv6 Host Functions 35-1

Understanding IPv6 35-2

IPv6 Addresses 35-2 Supported IPv6 Host Features 35-3

128-Bit Wide Unicast Addresses 35-3 DNS for IPv6 35-3 ICMPv6 35-4 Neighbor Discovery 35-4 IPv6 Stateless Autoconfiguration and Duplicate Address Detection 35-4 IPv6 Applications 35-4 Dual IPv4 and IPv6 Protocol Stacks 35-4 SNMP and Syslog Over IPv6 35-5 HTTP(S) Over IPv6 35-6

IPv6 and Switch Stacks 35-6

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Configuring IPv6 35-7

Default IPv6 Configuration 35-7 Configuring IPv6 Addressing and Enabling IPv6 Host 35-7 Configuring IPv6 ICMP Rate Limiting 35-9 Configuring Static Routes for IPv6 35-10

Displaying IPv6 35-11

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Contents

CHAPTER

36 Configuring IPv6 MLD Snooping 36-1

Understanding MLD Snooping 36-1

MLD Messages 36-2 MLD Queries 36-3 Multicast Client Aging Robustness 36-3 Multicast Router Discovery 36-3 MLD Reports 36-4 MLD Done Messages and Immediate-Leave 36-4 Topology Change Notification Processing 36-5 MLD Snooping in Switch Stacks 36-5

Configuring IPv6 MLD Snooping 36-5

Default MLD Snooping Configuration 36-6 MLD Snooping Configuration Guidelines 36-6 Enabling or Disabling MLD Snooping 36-7 Configuring a Static Multicast Group 36-8 Configuring a Multicast Router Port 36-8 Enabling MLD Immediate Leave 36-9 Configuring MLD Snooping Queries 36-10 Disabling MLD Listener Message Suppression 36-11

CHAPTER

Displaying MLD Snooping Information 36-12

37 Configuring EtherChannels and Link-State Tracking 37-1

Understanding EtherChannels 37-2

EtherChannel Overview 37-2 Port-Channel Interfaces 37-4 Port Aggregation Protocol 37-5

PAgP Modes 37-6

PAgP Interaction with Virtual Switches and Dual-Active Detection 37-6

PAgP Interaction with Other Features 37-7 Link Aggregation Control Protocol 37-7

LACP Modes 37-7

LACP Interaction with Other Features 37-8 EtherChannel On Mode 37-8 Load Balancing and Forwarding Methods 37-8 EtherChannel and Switch Stacks 37-10

Configuring EtherChannels 37-11

Default EtherChannel Configuration 37-11 EtherChannel Configuration Guidelines 37-12 Configuring Layer 2 EtherChannels 37-13

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Configuring EtherChannel Load Balancing 37-15 Configuring the PAgP Learn Method and Priority 37-16 Configuring LACP Hot-Standby Ports 37-18

Configuring the LACP System Priority 37-18 Configuring the LACP Port Priority 37-19

Displaying EtherChannel, PAgP, and LACP Status 37-20

Understanding Link-State Tracking 37-20

Configuring Link-State Tracking 37-23

Default Link-State Tracking Configuration 37-23 Link-State Tracking Configuration Guidelines 37-23 Configuring Link-State Tracking 37-23 Displaying Link-State Tracking Status 37-24

Contents

CHAPTER

38 Troubleshooting 38-1

Recovering from a Software Failure 38-2

Recovering from a Lost or Forgotten Password 38-3

Procedure with Password Recovery Enabled 38-4 Procedure with Password Recovery Disabled 38-6

Preventing Switch Stack Problems 38-8

Recovering from a Command Switch Failure 38-8

Replacing a Failed Command Switch with a Cluster Member 38-9 Replacing a Failed Command Switch with Another Switch 38-11

Recovering from Lost Cluster Member Connectivity 38-12

Preventing Autonegotiation Mismatches 38-12

Troubleshooting Power over Ethernet Switch Ports 38-13

Disabled Port Caused by Power Loss 38-13 Disabled Port Caused by False Link Up 38-13

SFP Module Security and Identification 38-13

Monitoring SFP Module Status 38-14

Using Ping 38-14

Understanding Ping 38-14 Executing Ping 38-14

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Using Layer 2 Traceroute 38-15

Understanding Layer 2 Traceroute 38-15 Usage Guidelines 38-16 Displaying the Physical Path 38-17

Using IP Traceroute 38-17

Understanding IP Traceroute 38-17

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Contents

Executing IP Traceroute 38-18

Using TDR 38-19

Understanding TDR 38-19 Running TDR and Displaying the Results 38-19

Using Debug Commands 38-19

Enabling Debugging on a Specific Feature 38-20 Enabling All-System Diagnostics 38-20 Redirecting Debug and Error Message Output 38-21

Using the show platform forward Command 38-21

Using the crashinfo Files 38-23

Basic crashinfo Files 38-23 Extended crashinfo Files 38-23

Memory Consistency Check Routines 38-24

Displaying TCAM Memory Consistency Check Errors 38-24

APPENDIX

Troubleshooting Tables 38-25

Troubleshooting CPU Utilization 38-25

Possible Symptoms of High CPU Utilization 38-25

Verifying the Problem and Cause 38-26 Troubleshooting Power over Ethernet (PoE) 38-27 Troubleshooting Stackwise 38-30

A Supported MIBs A-1

MIB List A-1

Using FTP to Access the MIB Files A-3

B Working with the Cisco IOS File System, Configuration Files, and Software Images B-1

Working with the Flash File System B-1

Displaying Available File Systems B-2 Setting the Default File System B-3 Displaying Information about Files on a File System B-3 Changing Directories and Displaying the Working Directory B-4 Creating and Removing Directories B-4 Copying Files B-5 Deleting Files B-5 Creating, Displaying, and Extracting tar Files B-6

Creating a tar File B-6

Displaying the Contents of a tar File B-7

Extracting a tar File B-7

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Displaying the Contents of a File B-8

Working with Configuration Files B-8

Guidelines for Creating and Using Configuration Files B-9 Configuration File Types and Location n B-10 Creating a Configuration File By Using a Text Editor B-10 Copying Configuration Files By Using TFTP B-10

Preparing to Download or Upload a Configuration File B y Using TFTP B-10 Downloading the Configuration File By Using TFTP B-11 Uploading the Configuration File By Using TFTP B-12

Copying Configuration Files By Using FTP B-12

Preparing to Download or Upload a Configuration File By Using FTP B-13 Downloading a Configuration File By Using FTP B-13 Uploading a Configuration File By Using FTP B-14

Copying Configuration Files By Using RCP B-15

Preparing to Download or Upload a Configuration File By Using RCP B-16 Downloading a Configuration File By Using RCP B-17 Uploading a Configuration File By Using RCP B-18

Clearing Configuration Information B-18

Clearing the Startup Configuration File B-19 Deleting a Stored Configuration File B-19

Replacing and Rolling Back Configurations B-19

Understanding Configuration Replacement and Rollback B-19 Configuration Guidelines B-21 Configuring the Configuration Archive B-21 Performing a Configuration Replacement or Rollback Operation B-22

Contents

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Working with Software Images B-23

Image Location on the Switch B-24 tar File Format of Images on a Server or Cisco.com B-24 Copying Image Files By Using TFTP B-25

Preparing to Download or Upload an Image File By Using TFTP B-25 Downloading an Image File By Using TFTP B-26 Uploading an Image File By Using TFTP B-28

Copying Image Files By Using FTP B-28

Preparing to Download or Upload an Image File By Using FTP B-29 Downloading an Image File By Using FTP B-30 Uploading an Image File By Using FTP B-32

Copying Image Files By Using RCP B-33

Preparing to Download or Upload an Image File By Using RCP B-33 Downloading an Image File By Using RCP B-34 Uploading an Image File By Using RCP B-36

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Contents

Copying an Image File from One Stack Member to Another B-37

APPENDIX

C Unsupported Commands in Cisco IOS Release 12.2(55)SE C-1

Access Control Lists C-1

Unsupported Privileged EXEC Commands C-1 Unsupported Global Configuration Commands C-2 Unsupported Route-Map Configuration Commands C-2

Boot Loader Commands C-2

Unsupported Global Configuration Commands C-2

Debug Commands C-2

Unsupported Privileged EXEC Commands C-2

IGMP Snooping Commands C-2

Unsupported Global Configuration Commands C-2

Interface Commands C-3

Unsupported Privileged EXEC Commands C-3 Unsupported Global Configuration Commands C-3 Unsupported Interface Configuration Commands C-3

MAC Address Commands C-3

Unsupported Privileged EXEC Commands C-3 Unsupported Global Configuration Commands C-4

Miscellaneous C-4

Unsupported User EXEC Commands C-4 Unsupported Privileged EXEC Commands C-4 Unsupported Global Configuration Commands C-4

Network Address Translation (NAT) Commands C-4

Unsupported Privileged EXEC Commands C-4

QoS C-5

Unsupported Global Configuration Command C-5 Unsupported Interface Configuration Commands C-5 Unsupported Policy-Map Configuration Command C-5

RADIUS C-5

Unsupported Global Configuration Commands C-5

SNMP C-5

Unsupported Global Configuration Commands C-5

SNMPv3 C-6

Unsupported 3DES Encryption Commands C-6

Spanning Tree C-6

Unsupported Global Configuration Command C-6

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NDEX

Contents

Unsupported Interface Configuration Command C-6

VLAN C-6

Unsupported Global Configuration Command C-6 Unsupported vlan-config Command C-6 Unsupported User EXEC Commands C-6 Unsupported vlan-config Command C-6 Unsupported VLAN Database Commands C-7

VTP C-7

Unsupported Privileged EXEC Commands C-7

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Audience

Purpose

Preface

This guide is for the networking professional managing the Catalyst 2975 switch, hereafter referred to as the switch. Before using this guide, you should have experience working with the Cisco IOS software and be familiar with the concepts and terminology of Ethernet and local area networking.

This guide provides the information that you need to configure Cisco IOS software features on your switch.

The Catalyst 2975 switch is supported by the LAN base software image that provides enterprise-class intelligent services such as access control lists (ACLs) and quality of service (QoS) features.

This guide provides procedures for using the commands that have been created or changed for use with the switch. It does not provide detailed information about these commands. For detailed information about these commands, see the Catalyst 2975 Switch Command Reference for this release. For information about the standard Cisco IOS Release 12.2 commands, see the Cisco IOS documentation set available from the Cisco.com home page at Documentation > Cisco IOS Software.

This guide does not provide detailed information on the graphical user interfaces (GUIs) for the embedded device manager or for Cisco Network Assistant (hereafter referred to as Network Assistant) that you can use to manage the switch. However, the concepts in this guide are applicable to the GUI user. For information about the device manager, see the switch online help. For information about Network Assistant, see Getting Started with Cisco Network Assistant, available on Cisco.com.

This guide does not describe system messages you might encounter or how to install your switch. For more information, see the Catalyst 2975 Switch System Message Guide for this release and the Catalyst 2975 Switch Hardware Installation Guide.

For documentation updates, see the release notes for this release.

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Conventions

This publication uses these conventions to convey instructions and information:

Command descriptions use these conventions:

• Commands and keywords are in boldface text.

• Arguments for which you supply values are in italic.

• Square brackets ([ ]) mean optional elements.

• Braces ({ }) group required choices, and vertical bars ( | ) separate the alternative elements.

• Braces and vertical bars within square brackets ([{ | }]) mean a required choice within an optional

Interactive examples use these conventions:

• Terminal sessions and system displays are in screen font.

• Information you enter is in boldface screen font.

• Nonprinting characters, such as passwords or tabs, are in angle brackets (< >).

Notes, cautions, and timesavers use these conventions and symbols:

Preface

element.

Note Means reader take note. Notes contain helpful suggestions or references to materials not contained in

this manual.

Caution Means reader be careful. In this situation, you might do something that could result in equipment

damage or loss of data.

Related Publications

These documents provide complete information about the switch and are available from this Cisco.com site:

http://www.cisco.com/en/US/products/ps10081/tsd_products_support_series_home.html

Note Before installing, configuring, or upgrading the switch, see these documents:

• For initial configuration information, see the “Using Express Setup” section in the getting started

guide or the “Configuring the Switch with the CLI-Based Setup Program” appendix in the hardware installation guide.

• For device manager requirements, see the “System Requirements” section in the release notes (not

orderable but available on Cisco.com).

• For Network Assistant requirements, see the Getting Started with Cisco Network Assistant (not

orderable but available on Cisco.com).

• For cluster requirements, see the Release Notes for Cisco Network Assistant (not orderable but

available on Cisco.com).

• For upgrading information, see the “Downloading Software” section in the release notes.

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Preface

See these documents for other information about the switch:

• Catalyst 3750, 3560, 3550, 2975, 2975, 2970, and 2960 and 2960-S Switch System Message Guide

• Release Notes for the Catalyst 2975 Switch

• Catalyst 2975 Switch Software Configuration Guide

• Catalyst 2975 Switch Command Reference

• Catalyst 2975 Switch Hardware Installation Guide

• Catalyst 2975 Switch Getting Started Guide

• Regulatory Compliance and Safety Information for the Catalyst 2975 Switch

• Auto Smartports Configuration Guide

• Getting Started with Cisco Network Assistant

• Release Notes for Cisco Network Assistant

• Cisco RPS 675 Redundant Power System Hardware Installation Guide

• Cisco Redundant Power System 2300 Hardware Installation Guide

• For information about the Network Admission Control (NAC) features, see the Network Admission

Control Software Configuration Guide

• Information about Cisco SFP, SFP+, and GBIC modules is available from this Cisco.com site:

http://www.cisco.com/en/US/products/hw/modules/ps5455/prod_installation_guides_list.html

SFP compatibility matrix documents are available from this Cisco.com site:

http://www.cisco.com/en/US/products/hw/modules/ps5455/products_device_support_tables_list.h tml

Obtaining Documentation, Obtaining Support, and Security Guidelines

For information on obtaining documentation, submitting a service request, and gathering additional information, see the monthly What’s New in Cisco Product Documentation, which also lists all new and revised Cisco technical documentation:

http://www.cisco.com/en/US/docs/general/whatsnew/whatsnew.html

Subscribe to the What’s New in Cisco Product Documentation as a Really Simple Syndication (RSS) feed and set content to be delivered directly to your desktop using a reader application. The RSS feeds are a free service and Cisco currently supports RSS version 2.0.

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Preface

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Features

CHAP TER

Overview

This chapter provides these topics about the Catalyst 2975 switch software:

• Features, page 1-1

• Default Settings After Initial Switch Configuration, page 1-13

• Network Configuration Examples, page 1-15

• Where to Go Next, page 1-21

Unless otherwise noted, the term switch refers to a standalone switch and to a switch stack.

In this document, IP refers to IP Version 4 (IPv4) unless there is a specific reference to IP Version 6 (IPv6).

Some features described in this chapter are available only on the cryptographic (supports encryption) version of the software. You must obtain authorization to use this feature and to download the cryptographic version of the software from Cisco.com. For more information, see the release notes for this release.

• Ease-of-Deployment and Ease-of-Use Features, page 1-2

• Performance Features, page 1-3

• Management Options, page 1-5

• Manageability Features, page 1-5

• Availability and Redundancy Features, page 1-7

• VLAN Features, page 1-8

• Security Features, page 1-8

• QoS and CoS Features, page 1-11

• Power over Ethernet Features, page 1-12

• Monitoring Features, page 1-12

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Features

Ease-of-Deployment and Ease-of-Use Features

• Express Setup for quickly configuring a switch for the first time with basic IP information, contact

information, switch and Telnet passwords, and Simple Network Management Protocol (SNMP) information through a browser-based program. For more information about Express Setup, see the getting started guide.

• User-defined and Cisco-default Smartports macros for creating custom switch configurations for

simplified deployment across the network.

• An embedded device manager GUI for configuring and monitoring a single switch through a web

browser. For information about launching the device manager, see the getting started guide. For more information about the device manager, see the switch online help.

• Cisco Network Assistant (hereafter referred to as Network Assistant) for

–

Managing communities, which are device groups like clusters, except that they can contain routers and access points and can be made more secure.

–

Simplifying and minimizing switch, switch stack, and switch cluster management from anywhere in your intranet.

–

Accomplishing multiple configuration tasks from a single graphical interface without needing to remember command-line interface (CLI) commands to accomplish specific tasks.

Chapter 1 Overview

–

Interactive guide mode that guides you in configuring complex features such as VLANs, ACLs, and quality of service (QoS).

–

Configuration wizards that prompt you to provide only the minimum required information to configure complex features such as QoS priorities for traffic, priority levels for data applications, and security.

–

Downloading an image to a switch.

–

Applying actions to multiple ports and multiple switches at the same time, such as VLAN and QoS settings, inventory and statistic reports, link- and switch-level monitoring and troubleshooting, and multiple switch software upgrades.

–

Viewing a topology of interconnected devices to identify existing switch clusters and eligible switches that can join a cluster and to identify link information between switches.

–

Monitoring real-time status of a switch or multiple switches from the LEDs on the front-panel images. The system, redundant power system (RPS), and port LED colors on the images are similar to those used on the physical LEDs.

Note The Network Assistant must be downloaded from cisco.com/go/cna.

–

Connecting up to nine switches through their stack ports and operating as a single switch or switch-router in the network.

–

Creating a bidirectional 32-Gb/s switching fabric across the switch stack, where all stack members have full access to the system bandwidth.

–

Using a single IP address and configuration file to manage the entire switch stack.

–

Automatic Cisco IOS version-check of new stack members with the option to automatically load images from the stack master or from a TFTP server.

1-2

–

Adding, removing, and replacing switches in the stack without disrupting the operation of the stack.

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Chapter 1 Overview

–

Provisioning a new member for a switch stack with the offline configuration feature. You can configure in advance the interface configuration for a specific stack member number and for a specific switch type of a new switch that is not part of the stack. The switch stack retains this information across stack reloads whether or not the provisioned switch is part of the stack.

–

Displaying stack-ring activity statistics (the number of frames sent by each stack member to the ring).

• Switch clustering technology for

–

Unified configuration, monitoring, authentication, and software upgrade of multiple, cluster-capable switches, regardless of their geographic proximity and interconnection media, including Ethernet, Fast Ethernet, Fast EtherChannel, small form-factor pluggable (SFP) modules, Gigabit Ethernet, and Gigabit EtherChannel connections. For a list of cluster-capable switches, see the release notes.

–

Automatic discovery of candidate switches and creation of clusters of up to 16 switches that can be managed through a single IP address.

–

Extended discovery of cluster candidates that are not directly connected to the command switch.

• Stack troubleshooting enhancements

• Auto Smartports

Features

–

Cisco-default and user-defined macros for dynamic port configuration based on the device type detected on the port.

–

Enhancements to add support for global macros, last-resort macros, event trigger control, access points, EtherChannels, auto-QoS with Cisco Medianet, and IP phones.

–

Enhancements to add support for macro persistency, LLDP-based triggers, MAC address and OUI-based triggers, remote macros as well as for automatic configuration based on these two new device types: Cisco Digital Media Player (Cisco DMP) and Cisco IP Video Surveillance Camera (Cisco IPVSC).

For information, see the Auto Smartports Configuration Guide.

• Smart Install to allow a single point of management (director) in a network. You can use Smart

Install to provide zero touch image and configuration upgrade of newly deployed switches and image and configuration downloads for any client switches. For more information, see the Cisco

Smart Install Configuration Guide.

• Smart Install enhancements in Cisco IOS Release 12.2(55)SE supporting client backup files,

zero-touch replacement for clients with the same product-ID, automatic generation of the image list file, configurable file repository, hostname changes, transparent connection of the director to client, and USB storage for image and seed configuration.

Performance Features

• Cisco EnergyWise manages the energy usage of end points including power over Ethernet (PoE)

devices and non-Cisco devices. For information, see the Cisco EnergyWise Configuration Guide.

• Autosensing of port speed and autonegotiation of duplex mode on all switch ports for optimizing

bandwidth.

• Automatic-medium-dependent interface crossover (auto-MDIX) capability on 10/100/1000 Mb/s

interfaces and on 10/100/1000 BASE-TX SFP module interfaces that enables the interface to automatically detect the required cable connection type (straight-through or crossover) and to configure the connection appropriately.

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Features

Chapter 1 Overview

• Support for up to 9000 bytes for frames that are bridged in hardware and up to 2000 bytes for frames

that are bridged by software

• IEEE 802.3x flow control on all ports (the switch does not send pause frames).

• Up to 32 Gb/s of forwarding rates in a switch stack.

• EtherChannel for enhanced fault tolerance and for providing up to 8 Gb/s (Gigabit EtherChannel)

or 800 Mb/s (Fast EtherChannel) full-duplex bandwidth among switches, routers, and servers.

• Port Aggregation Protocol (PAgP) and Link Aggregation Control Protocol (LACP) for automatic

creation of EtherChannel links.

• Forwarding of Layer 2 packets at Gigabit line rate across the switches in the stack.

• Forwarding of Layer 2 packets at Gigabit line rate

• Per-port storm control for preventing broadcast, multicast, and unicast storms.

• Port blocking on forwarding unknown Layer 2 unknown unicast, multicast, and bridged broadcast

traffic.

• Internet Group Management Protocol (IGMP) snooping for IGMP Versions 1, 2, and 3 for

efficiently forwarding multimedia and multicast traffic

• IGMP report suppression for sending only one IGMP report per multicast router query to the

multicast devices (supported only for IGMPv1 or IGMPv2 queries).

• IGMP snooping querier support to configure switch to generate periodic IGMP general query

messages.

• IPv6 host support for basic IPv6 management

• Multicast Listener Discovery (MLD) snooping to enable efficient distribution of IP version 6 (IPv6)

multicast data to clients and routers in a switched network

• Multicast VLAN registration (MVR) to continuously send multicast streams in a multicast VLAN

while isolating the streams from subscriber VLANs for bandwidth and security reasons.

• IGMP filtering for controlling the set of multicast groups to which hosts on a switch port can belong.

• IGMP throttling for configuring the action when the maximum number of entries is in the IGMP

forwarding table.

• IGMP leave timer for configuring the leave latency for the network.

• Switch Database Management (SDM) templates for allocating system resources to maximize

support for user-selected features.

• Support for Cisco IOS IP Service Level Agreements (SLAs) responder that allows the system to

anticipate and respond to Cisco IOS IP SLAs request packets for monitoring network performance.

• Configurable small-frame arrival threshold to prevent storm control when small frames (64 bytes or

less) arrive on an interface at a specified rate (the threshold).

• Flex Link Multicast Fast Convergence to reduce the multicast traffic convergence time after a Flex

Link failure.

• RADIUS server load balancing to allow access and authentication requests to be distributed evenly

across a server group.

• Support for QoS marking of CPU-generated traffic and queue CPU-generated traffic on the egress

network ports.

• Memory consistency check routines to detect and correct invalid ternary content addressable

memory (TCAM) table entries.

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Chapter 1 Overview

Management Options

• An embedded device manager—The device manager is a GUI that is integrated in the software

image. You use it to configure and to monitor a single switch. For information about launching the device manager, see the getting started guide. For more information about the device manager, see the switch online help.

• Network Assistant—Network Assistant is a network management application that can be

downloaded from Cisco.com. You use it to manage a single switch, a cluster of switches, or a community of devices. For more information about Network Assistant, see Getting Started with Cisco Network Assistant, available on Cisco.com.

• CLI—The Cisco IOS software supports desktop- and multilayer-switching features. You can access

the CLI by connecting your management station directly to the switch console port, by connecting your PC directly to the Ethernet management port, or by using Telnet from a remote management station or PC. You can manage the switch stack by connecting to the console port or Ethernet management port of any stack member. For more information about the CLI, see Chapter 2, “Using

the Command-Line Interface.”

• SNMP—SNMP management applications such as CiscoWorks2000 LAN Management Suite (LMS)

and HP OpenView. You can manage from an SNMP-compatible management station that is running platforms such as HP OpenView or SunNet Manager. The switch supports a comprehensive set of MIB extensions and four remote monitoring (RMON) groups. For more information about using SNMP, see Chapter 30, “Configuring SNMP.”

Features

• Cisco IOS Configuration Engine (previously known to as the Cisco IOS CNS

agent)-—Configuration service automates the deployment and management of network devices and services. You can automate initial configurations and configuration updates by generating switch-specific configuration changes, sending them to the switch, executing the configuration change, and logging the results.

For more information about CNS, see Chapter 4, “Configuring Cisco IOS Configuration Engine.”

Manageability Features

• CNS embedded agents for automating switch management, configuration storage, and delivery

• DHCP for automating configuration of switch information (such as IP address, default gateway,

hostname, and Domain Name System [DNS] and TFTP server names)

• DHCP relay for forwarding User Datagram Protocol (UDP) broadcasts, including IP address

requests, from DHCP clients

• DHCP server for automatic assignment of IP addresses and other DHCP options to IP hosts

• DHCP-based autoconfiguration and image update to download a specified configuration a new

image to a large number of switches

• DHCP server port-based address allocation for the preassignment of an IP address to a switch port

• Directed unicast requests to a DNS server for identifying a switch through its IP address and its

corresponding hostname and to a TFTP server for administering software upgrades from a TFTP server

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• Address Resolution Protocol (ARP) for identifying a switch through its IP address and its

corresponding MAC address

• Unicast MAC address filtering to drop packets with specific source or destination MAC addresses

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Features

Chapter 1 Overview

• Configurable MAC address scaling that allows disabling MAC address learning on a VLAN to limit

the size of the MAC address table

• Cisco Discovery Protocol (CDP) Versions 1 and 2 for network topology discovery and mapping

between the switch and other Cisco devices on the network

• Link Layer Discovery Protocol (LLDP) and LLDP Media Endpoint Discovery (LLDP-MED) for

interoperability with third-party IP phones

• LLDP media extensions (LLDP-MED) location TLV that provides location information from the

switch to the endpoint device

• Support for CDP and LLDP enhancements for exchanging location information with video end

points for dynamic location-based content distribution from servers

• Network Time Protocol (NTP) for providing a consistent time stamp to all switches from an external

source

• Cisco IOS File System (IFS) for providing a single interface to all file systems that the switch uses

• Configuration logging to log and to view changes to the switch configuration

• Unique device identifier to provide product identification information through a show inventory

user EXEC command display

• In-band management access through the device manager over a Netscape Navigator or Microsoft

Internet Explorer browser session

• In-band management access for up to 16 simultaneous Telnet connections for multiple CLI-based

sessions over the network

• In-band management access for up to five simultaneous, encrypted Secure Shell (SSH) connections

for multiple CLI-based sessions over the network

• In-band management access through SNMP Versions 1, 2c, and 3 get and set requests

• Out-of-band management access through the switch console port to a directly attached terminal or

to a remote terminal through a serial connection or a modem

• Secure Copy Protocol (SCP) feature to provide a secure and authenticated method for copying

switch configuration or switch image files (requires the cryptographic version of the software)

• Configuration replacement and rollback to replace the running configuration on a switch with any

saved Cisco IOS configuration file

• The HTTP client in Cisco IOS supports can send requests to both IPv4 and IPv6 HTTP server, and

the HTTP server in Cisco IOS can service HTTP requests from both IPv4 and IPv6 HTTP clients

• Simple Network and Management Protocol (SNMP) can be configured over IPv6 transport so that

an IPv6 host can send SNMP queries and receive SNMP notifications from a device running IPv6

• IPv6 stateless autoconfiguration to manage link, subnet, and site addressing changes, such as

management of host and mobile IP addresses

• Disabling MAC address learning on a VLAN

• DHCP server port-based address allocation for the preassignment of an IP address to a switch port.

• Wired location service sends location and attachment tracking information for connected devices to

a Cisco Mobility Services Engine (MSE)

• CPU utilization threshold trap monitors CPU utilization

• LLDP-MED network-policy profile time, length, value (TLV) for creating a profile for voice and

voice-signalling by specifying the values for VLAN, class of service (CoS), differentiated services code point (DSCP), and tagging mode

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Chapter 1 Overview

• Support for including a hostname in the option 12 field of DHCPDISCOVER packets. This provides

identical configuration files to be sent by using the DHCP protocol

• DHCP Snooping enhancement to support the selection of a fixed string-based format for the

circuit-id sub-option of the Option 82 DHCP field

• Increased support for LLPD-MED by allowing the switch to grant power to the power device (PD),

based on the power policy TLV request

Availability and Redundancy Features

• Automatic stack master re-election for replacing stack masters that become unavailable (failover

support)

The newly elected stack master begins accepting Layer 2 traffic in less than 1 second and Layer 3 traffic between 3 to 5 seconds.

• Cross-stack EtherChannel for providing redundant links across the switch stack

• UniDirectional Link Detection (UDLD) and aggressive UDLD for detecting and disabling

unidirectional links on fiber-optic interfaces caused by incorrect fiber-optic wiring or port faults

• IEEE 802.1D Spanning Tree Protocol (STP) for redundant backbone connections and loop-free

networks. STP has these features:

–

Up to 128 spanning-tree instances supported

Features

–

Per-VLAN spanning-tree plus (PVST+) for load balancing across VLANs

–

Rapid PVST+ for load balancing across VLANs and providing rapid convergence of spanning-tree instances

–

UplinkFast, cross-stack UplinkFast, and BackboneFast for fast convergence after a spanning-tree topology change and for achieving load balancing between redundant uplinks, including Gigabit uplinks and cross-stack Gigabit uplinks

• IEEE 802.1s Multiple Spanning Tree Protocol (MSTP) for grouping VLANs into a spanning-tree

instance and for providing multiple forwarding paths for data traffic and load balancing and rapid per-VLAN Spanning-Tree plus (rapid-PVST+) based on the IEEE 802.1w Rapid Spanning Tree Protocol (RSTP) for rapid convergence of the spanning tree by immediately changing root and designated ports to the forwarding state

• Optional spanning-tree features available in PVST+, rapid-PVST+, and MSTP mode:

–

Port Fast for eliminating the forwarding delay by enabling a port to immediately change from the blocking state to the forwarding state

–

BPDU guard for shutting down Port Fast-enabled ports that receive bridge protocol data units (BPDUs)

–

BPDU filtering for preventing a Port Fast-enabled port from sending or receiving BPDUs

–

Root guard for preventing switches outside the network core from becoming the spanning-tree root

–

Loop guard for preventing alternate or root ports from becoming designated ports because of a failure that leads to a unidirectional link

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Features

VLAN Features

Chapter 1 Overview

• Flex Link Layer 2 interfaces to back up one another as an alternative to STP for basic link

redundancy

• Link-state tracking to mirror the state of the ports that carry upstream traffic from connected hosts

and servers, and to allow the failover of the server traffic to an operational link on another Cisco Ethernet switch.

• Support for up to 255 VLANs for assigning users to VLANs associated with appropriate network

resources, traffic patterns, and bandwidth

• Support for VLAN IDs in the 1 to 4094 range as allowed by the IEEE 802.1Q standard

• VLAN Query Protocol (VQP) for dynamic VLAN membership

• IEEE 802.1Q trunking encapsulation on all ports for network moves, adds, and changes;

management and control of broadcast and multicast traffic; and network security by establishing VLAN groups for high-security users and network resources

• Dynamic Trunking Protocol (DTP) for negotiating trunking on a link between two devices and for

negotiating the type of trunking encapsulation (IEEE 802.1Q) to be used

• VLAN Trunking Protocol (VTP) and VTP pruning for reducing network traffic by restricting

flooded traffic to links destined for stations receiving the traffic

• Voice VLAN for creating subnets for voice traffic from Cisco IP Phones

• VLAN 1 minimization for reducing the risk of spanning-tree loops or storms by allowing VLAN 1

• VLAN Flex Link Load Balancing to provide Layer 2 redundancy without requiring Spanning Tree

• Support for 802.1x authentication with restricted VLANs (also known as authentication failed

• Support for VTP version 3 that includes support for configuring extended range VLANs (VLANs

Security Features

• IP Service Level Agreements (IP SLAs) responder support that allows the switch to be a target

• Web authentication to allow a supplicant (client) that does not support IEEE 802.1x functionality to

• Local web authentication banner so that a custom banner or an image file can be displayed at a web

• Password-protected access (read-only and read-write access) to management interfaces (device

to be disabled on any individual VLAN trunk link. With this feature enabled, no user traffic is sent or received on the trunk. The switch CPU continues to send and receive control protocol frames.

Protocol (STP). A pair of interfaces configured as primary and backup links can load balance traffic based on VLAN.

VLANs)

1006 to 4094) in any VTP mode, enhanced authentication (hidden or secret passwords), propagation of other databases in addition to VTP, VTP primary and secondary servers, and the option to turn VTP on or off by port

device for IP SLAs active traffic monitoring

be authenticated using a web browser

authentication login screen

manager, Network Assistant, and the CLI) for protection against unauthorized configuration changes

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Chapter 1 Overview

Features

• Multilevel security for a choice of security level, notification, and resulting actions

• Static MAC addressing for ensuring security

• Protected port option for restricting the forwarding of traffic to designated ports on the same switch

• Port security option for limiting and identifying MAC addresses of the stations allowed to access

the port

• VLAN aware port security option to shut down the VLAN on the port when a violation occurs,

instead of shutting down the entire port.

• Port security aging to set the aging time for secure addresses on a port

• BPDU guard for shutting down a Port Fast-configured port when an invalid configuration occurs

• Standard and extended IP access control lists (ACLs) for defining inbound security policies on

Layer 2 interfaces (port ACLs)

• Extended MAC access control lists for defining security policies in the inbound direction on Layer 2

interfaces

• Source and destination MAC-based ACLs for filtering non-IP traffic

• DHCP snooping to filter untrusted DHCP messages between untrusted hosts and DHCP servers

• IP source guard to restrict traffic on nonrouted interfaces by filtering traffic based on the DHCP

snooping database and IP source bindings

• Dynamic ARP inspection to prevent malicious attacks on the switch by not relaying invalid ARP

requests and responses to other ports in the same VLAN

• IEEE 802.1x port-based authentication to prevent unauthorized devices (clients) from gaining

access to the network. These features are supported:

–

Multidomain authentication (MDA) to allow both a data device and a voice device, such as an IP phone (Cisco or non-Cisco), to independently authenticate on the same IEEE 802.1x-enabled switch port

–

Dynamic voice virtual LAN (VLAN) for MDA to allow a dynamic voice VLAN on an MDA-enabled port

–

VLAN assignment for restricting 802.1x-authenticated users to a specified VLAN

–

Support for VLAN assignment on a port configured for multi-auth mode. The RADIUS server assigns a VLAN to the first host to authenticate on the port, and subsequent hosts use the same VLAN. Voice VLAN assignment is supported for one IP phone.

–

Port security for controlling access to 802.1x ports

–

Voice VLAN to permit a Cisco IP Phone to access the voice VLAN regardless of the authorized or unauthorized state of the port

–

IP phone detection enhancement to detect and recognize a Cisco IP phone.

–

Guest VLAN to provide limited services to non-802.1x-compliant users

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Restricted VLAN to provide limited services to users who are 802.1x compliant, but do not have the credentials to authenticate via the standard 802.1x processes

–

802.1x accounting to track network usage

–

802.1x with wake-on-LAN to allow dormant PCs to be powered on based on the receipt of a specific Ethernet frame

–

802.1x readiness check to determine the readiness of connected end hosts before configuring IEEE 802.1x on the switch

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Features

Chapter 1 Overview

–

Voice aware 802.1x security to apply traffic violation actions only on the VLAN on which a security violation occurs.

–

MAC authentication bypass to authorize clients based on the client MAC address.

–

Network Admission Control (NAC) Layer 2 802.1x validation of the antivirus condition or posture of endpoint systems or clients before granting the devices network access.

For information about configuring NAC Layer 2 802.1x validation, see the “Configuring NAC

Layer 2 802.1x Validation” section on page 10-59.

–

Network Edge Access Topology (NEAT) with 802.1X switch supplicant, host authorization with CISP, and auto enablement to authenticate a switch outside a wiring closet as a supplicant to another switch.

–

IEEE 802.1x with open access to allow a host to access the network before being authenticated.

–

IEEE 802.1x authentication with downloadable ACLs and redirect URLs to allow per-user ACL downloads from a Cisco Secure ACS server to an authenticated switch.

–

Support for dynamic creation or attachment of an auth-default ACL on a port that has no configured static ACLs.

–

Flexible-authentication sequencing to configure the order of the authentication methods that a port tries when authenticating a new host.

–

Multiple-user authentication to allow more than one host to authenticate on an 802.1x-enabled port.

• TACACS+, a proprietary feature for managing network security through a TACACS server

• RADIUS for verifying the identity of, granting access to, and tracking the actions of remote users

through authentication, authorization, and accounting (AAA) services

• Secure Socket Layer (SSL) Version 3.0 support for the HTTP 1.1 server authentication, encryption,

and message integrity and HTTP client authentication to allow secure HTTP communications (requires the cryptographic version of the software)

• IEEE 802.1x Authentication with ACLs and the RADIUS Filter-Id Attribute

• Support for IP source guard on static hosts.

• RADIUS Change of Authorization (CoA) to change the attributes of a certain session after it is

authenticated. When there is a change in policy for a user or user group in AAA, administrators can send the RADIUS CoA packets from the AAA server, such as Cisco Secure ACS to reinitialize authentication, and apply to the new policies.

• IEEE 802.1x User Distribution to allow deployments with multiple VLANs (for a group of users) to

improve scalability of the network by load balancing users across different VLANs. Authorized users are assigned to the least populated VLAN in the group, assigned by RADIUS server.

• Support for critical VLAN with multiple-host authentication so that when a port is configured for

multi-auth, and an AAA server becomes unreachable, the port is placed in a critical VLAN in order to still permit access to critical resources.

• Customizable web authentication enhancement to allow the creation of user-defined login, success,

failure and expire web pages for local web authentication.

• Support for Network Edge Access Topology (NEAT) to change the port host mode and to apply a

standard port configuration on the authenticator switch port.

• VLAN-ID based MAC authentication to use the combined VLAN and MAC address information for

user authentication to prevent network access from unauthorized VLANs.

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Chapter 1 Overview

• MAC move to allow hosts (including the hosts connected behind an IP phone) to move across ports

within the same switch without any restrictions to enable mobility. With MAC move, the switch treats the reappearance of the same MAC address on another port in the same way as a completely new MAC address.

• Support for 3DES and AES with version 3 of the Simple Network Management Protocol (SNMPv3).

This release adds support for the 168-bit Triple Data Encryption Standard (3DES) and the 128-bit, 192-bit, and 256-bit Advanced Encryption Standard (AES) encryption algorithms to SNMPv3.

QoS and CoS Features

• Automatic QoS (auto-QoS) to simplify the deployment of existing QoS features by classifying

traffic and configuring egress queues

• Cross-stack QoS for configuring QoS features to all switches in a switch stack rather than on an

individual-switch basis

• Classification

–

IP type-of-service/Differentiated Services Code Point (IP ToS/DSCP) and IEEE 802.1p CoS marking priorities on a per-port basis for protecting the performance of mission-critical applications

Features

–

IP ToS/DSCP and IEEE 802.1p CoS marking based on flow-based packet classification (classification based on information in the MAC, IP, and TCP/UDP headers) for high-performance quality of service at the network edge, allowing for differentiated service levels for different types of network traffic and for prioritizing mission-critical traffic in the network

–

Trusted port states (CoS, DSCP, and IP precedence) within a QoS domain and with a port bordering another QoS domain

–

Trusted boundary for detecting the presence of a Cisco IP Phone, trusting the CoS value received, and ensuring port security

• Policing

–

Traffic-policing policies on the switch port for managing how much of the port bandwidth should be allocated to a specific traffic flow

–

If you configure multiple class maps for a hierarchical policy map, each class map can be associated with its own port-level (second-level) policy map. Each second-level policy map can have a different policer.

–

Aggregate policing for policing traffic flows in aggregate to restrict specific applications or traffic flows to metered, predefined rates

• Out-of-Profile

–

Out-of-profile markdown for packets that exceed bandwidth utilization limits

• Ingress queueing and scheduling

–

Two configurable ingress queues for user traffic (one queue can be the priority queue)

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–

Weighted tail drop (WTD) as the congestion-avoidance mechanism for managing the queue lengths and providing drop precedences for different traffic classifications

–

Shaped round robin (SRR) as the scheduling service for specifying the rate at which packets are sent to the stack ring (sharing is the only supported mode on ingress queues)

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Features

• Egress queues and scheduling

• Auto-QoS enhancements that add automatic configuration classification of traffic flow from video

Layer 3 Features

• When you configure the lanbase-routing SDM template, the switch supports static routing and

• IPv6 default router preference (DRP) for improving the ability of a host to select an appropriate

Chapter 1 Overview

–

Four egress queues per port

–

WTD as the congestion-avoidance mechanism for managing the queue lengths and providing drop precedences for different traffic classifications

–

SRR as the scheduling service for specifying the rate at which packets are dequeued to the egress interface (shaping or sharing is supported on egress queues). Shaped egress queues are guaranteed but limited to using a share of port bandwidth. Shared egress queues are also guaranteed a configured share of bandwidth, but can use more than the guarantee if other queues become empty and do not use their share of the bandwidth.

devices, such as the Cisco Telepresence System and Cisco Surveillance Camera.

router ACLs on SVIs

router

Power over Ethernet Features

• Ability to provide power to connected Cisco pre-standard and IEEE 802.3af-compliant powered

devices from Power over Ethernet (PoE)-capable ports if the switch detects that there is no power on the circuit.

• Support for CDP with power consumption. The powered device notifies the switch of the amount of

power it is consuming.

• Support for Cisco intelligent power management. The powered device and the switch negotiate

through power-negotiation CDP messages for an agreed power-consumption level. The negotiation allows a high-power Cisco powered device to operate at its highest power mode.

• Automatic detection and power budgeting; the switch maintains a power budget, monitors and tracks

requests for power, and grants power only when it is available.

• Ability to monitor the real-time power consumption. On a per-PoE port basis, the switch senses the

total power consumption, polices the power usage, and reports the power usage.

Monitoring Features

• Switch LEDs that provide port- and switch-level status

• Switch LEDs that provide port-, switch-, and stack-level status

• MAC address notification traps and RADIUS accounting for tracking users on a network by storing

the MAC addresses that the switch has learned or removed

1-12

• Switched Port Analyzer (SPAN) and Remote SPAN (RSPAN) for traffic monitoring on any port or

VLAN

• SPAN and RSPAN support of Intrusion Detection Systems (IDS) to monitor, repel, and report

network security violations

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Chapter 1 Overview

Default Settings After Initial Switch Configuration

• Four groups (history, statistics, alarms, and events) of embedded RMON agents for network

monitoring and traffic analysis

• Syslog facility for logging system messages about authentication or authorization errors, resource

issues, and time-out events

• Layer 2 traceroute to identify the physical path that a packet takes from a source device to a

destination device

• Time Domain Reflector (TDR) to diagnose and resolve cabling problems on 10/100/1000 copper

Ethernet ports

• SFP module diagnostic management interface to monitor physical or operational status of an SFP

module

Default Settings After Initial Switch Configuration

The switch is designed for plug-and-play operation, requiring only that you assign basic IP information to the switch and connect it to the other devices in your network. If you have specific network needs, you can change the interface-specific and system- and stack-wide settings.

Note For information about assigning an IP address by using the browser-based Express Setup program, see

the getting started guide. For information about assigning an IP address by using the CLI-based setup program, see the hardware installation guide.

If you do not configure the switch at all, the switch operates with these default settings:

• Default switch IP address, subnet mask, and default gateway is 0.0.0.0. For more information, see

Chapter 3, “Assigning the Switch IP Address and Default Gateway,” and Chapter 20, “Configuring DHCP Features and IP Source Guard Features.”

• Default domain name is not configured. For more information, see Chapter 3, “Assigning the Switch

IP Address and Default Gateway.”

• DHCP client is enabled, the DHCP server is enabled (only if the device acting as a DHCP server is

configured and is enabled), and the DHCP relay agent is enabled (only if the device is acting as a DHCP relay agent is configured and is enabled). For more information, see Chapter 3, “Assigning

the Switch IP Address and Default Gateway,” and Chapter 20, “Configuring DHCP Features and IP Source Guard Features.”

• Switch stack is enabled (not configurable). For more information, see Chapter 6, “Managing Switch

Stacks.”

• Switch cluster is disabled. For more information about switch clusters, see Chapter 5, “Clustering

Switches,” and the Getting Started with Cisco Network Assistant, available on Cisco.com.

• No passwords are defined. For more information, see Chapter 7, “Administering the Switch.”

• System name and prompt is Switch. For more information, see Chapter 7, “Administering the

Switch.”

• NTP is enabled. For more information, see Chapter 7, “Administering the Switch.”

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• DNS is enabled. For more information, see Chapter 7, “Administering the Switch.”

• TACACS+ is disabled. For more information, see Chapter 9, “Configuring Switch-Based

Authentication.”

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Default Settings After Initial Switch Configuration

• RADIUS is disabled. For more information, see Chapter 9, “Configuring Switch-Based

Authentication.”

• The standard HTTP server and Secure Socket Layer (SSL) HTTPS server are both enabled. For more

information, see Chapter 9, “Configuring Switch-Based Authentication.”

• IEEE 802.1x is disabled. For more information, see Chapter 10, “Configuring IEEE 802.1x

Port-Based Authentication.”

• Port parameters

–

Interface speed and duplex mode is autonegotiate. For more information, see Chapter 12,

“Configuring Interface Characteristics.”

–

Auto-MDIX is enabled. For more information, see Chapter 12, “Configuring Interface

Characteristics.”

–

Flow control is off. For more information, see Chapter 12, “Configuring Interface

Characteristics.”

–

PoE is autonegotiate. For more information, see Chapter 12, “Configuring Interface

Characteristics.”

• VLANs

–

Default VLAN is VLAN 1. For more information, see Chapter 13, “Configuring VLANs.”

–

VLAN trunking setting is dynamic auto (DTP). For more information, see Chapter 13,

“Configuring VLANs.”

Chapter 1 Overview

–

Trunk encapsulation is negotiate. For more information, see Chapter 13, “Configuring VLANs.”

–

VTP mode is server. For more information, see Chapter 15, “Configuring VTP.”

–

VTP version is Version 1. For more information, see Chapter 15, “Configuring VTP.”

–

Voice VLAN is disabled. For more information, see Chapter 14, “Configuring Voice VLAN.”

• STP, PVST+ is enabled on VLAN 1. For more information, see Chapter 16, “Configuring STP.”

• MSTP is disabled. For more information, see Chapter 17, “Configuring MSTP.”

• Optional spanning-tree features are disabled. For more information, see Chapter 18, “Configuring

Optional Spanning-Tree Features.”

• Flex Links are not configured. For more information, see Chapter 19, “Configuring Flex Links and

the MAC Address-Table Move Update Feature.”

• DHCP snooping is disabled. The DHCP snooping information option is enabled. For more

information, see Chapter 20, “Configuring DHCP Features and IP Source Guard Features.”

• IP source guard is disabled. For more information, see Chapter 20, “Configuring DHCP Features

and IP Source Guard Features.”

• DHCP server port-based address allocation is disabled. For more information, see Chapter 20,

“Configuring DHCP Features and IP Source Guard Features.”

• Dynamic ARP inspection is disabled on all VLANs. For more information, see Chapter 21,

“Configuring Dynamic ARP Inspection.”

• IGMP snooping is enabled. No IGMP filters are applied. For more information, see Chapter 22,

“Configuring IGMP Snooping and MVR.”

• IGMP throttling setting is deny. For more information, see Chapter 22, “Configuring IGMP

Snooping and MVR.”

1-14

• The IGMP snooping querier feature is disabled. For more information, see Chapter 22, “Configuring

IGMP Snooping and MVR.”

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Chapter 1 Overview

Network Configuration Examples

• MVR is disabled. For more information, see Chapter 22, “Configuring IGMP Snooping and MVR.”

• Port-based traffic

–

Broadcast, multicast, and unicast storm control is disabled. For more information, see

Chapter 23, “Configuring Port-Based Traffic Control.”

–

No protected ports are defined. For more information, see Chapter 23, “Configuring Port-Based

Traffic Control.”

–

Unicast and multicast traffic flooding is not blocked. For more information, see Chapter 23,

“Configuring Port-Based Traffic Control.”

–

No secure ports are configured. For more information, see Chapter 23, “Configuring Port-Based

Traffic Control.”

• CDP is enabled. For more information, see Chapter 24, “Configuring CDP.”

• UDLD is disabled. For more information, see Chapter 26, “Configuring UDLD.”

• SPAN and RSPAN are disabled. For more information, see Chapter 27, “Configuring SPAN and

RSPAN.”

• RMON is disabled. For more information, see Chapter 28, “Configuring RMON.”

• Syslog messages are enabled and appear on the console. For more information, see Chapter 29,

“Configuring System Message Logging.”

• SNMP is enabled (Version 1). For more information, see Chapter 30, “Configuring SNMP.”

• No ACLs are configured. For more information, see Chapter 31, “Configuring Network Security

with ACLs.”

• QoS is disabled. For more information, see Chapter 33, “Configuring QoS.”

• No EtherChannels are configured. For more information, see Chapter 37, “Configuring

EtherChannels and Link-State Tracking.”

Network Configuration Examples

This section provides network configuration concepts and includes examples of using the switch to create dedicated network segments and interconnecting the segments through Fast Ethernet and Gigabit Ethernet connections.

• “Design Concepts for Using the Switch” section on page 1-15

• “Small to Medium-Sized Network Using Catalyst 2975 Switches” section on page 1-19

• “Long-Distance, High-Bandwidth Transport Configuration” section on page 1-20

Design Concepts for Using the Switch

As your network users compete for network bandwidth, it takes longer to send and receive data. When you configure your network, consider the bandwidth required by your network users and the relative priority of the network applications that they use.

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Network Configuration Examples

Table 1-1 describes what can cause network performance to degrade and how you can configure your

network to increase the bandwidth available to your network users.

Table 1-1 Increasing Network Performance

Network Demands Suggested Design Methods

Too many users on a single network segment and a growing number of users accessing the Internet

• Increased power of new PCs,

workstations, and servers

• High bandwidth demand from

networked applications (such as e-mail with large attached files) and from bandwidth-intensive applications (such as multimedia)

• Create smaller network segments so that fewer users share the bandwidth, and use

VLANs and IP subnets to place the network resources in the same logical network as the users who access those resources most.

• Use full-duplex operation between the switch and its connected workstations.

• Connect global resources—such as servers and routers to which the network users

require equal access—directly to the high-speed switch ports so that they have their own high-speed segment.

• Use the EtherChannel feature between the switch and its connected servers and

routers.

Chapter 1 Overview

Bandwidth alone is not the only consideration when designing your network. As your network traffic profiles evolve, consider providing network services that can support applications for voice and data integration, multimedia integration, application prioritization, and security. Table 1 - 2 describes some network demands and how you can meet them.

Table 1-2 Providing Network Services

Network Demands Suggested Design Methods

Efficient bandwidth usage for multimedia applications and guaranteed bandwidth for critical applications

• Use IGMP snooping to efficiently forward multimedia and multicast traffic.

• Use other QoS mechanisms such as packet classification, marking, scheduling,

and congestion avoidance to classify traffic with the appropriate priority level, thereby providing maximum flexibility and support for mission-critical, unicast, and multicast and multimedia applications.

• Use MVR to continuously send multicast streams in a multicast VLAN but to

isolate the streams from subscriber VLANs for bandwidth and security reasons.

High demand on network redundancy and availability to provide always on mission-critical applications

• Use switch stacks, where all stack members are eligible stack masters in case of

stack-master failure. All stack members have synchronized copies of the saved and running configuration files of the switch stack.

• Use cross-stack EtherChannels for providing redundant links across the switch

stack.

• Use VLAN trunks, cross-stack UplinkFast, and BackboneFast for traffic-load

balancing on the uplink ports so that the uplink port with a lower relative port cost is selected to carry the VLAN traffic.

High demand on network redundancy and availability to provide always on mission-critical applications

• Use VLAN trunks and BackboneFast for traffic-load balancing on the uplink ports

so that the uplink port with a lower relative port cost is selected to carry the VLAN traffic.

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Network Configuration Examples

Table 1-2 Providing Network Services (continued)

Network Demands Suggested Design Methods

An evolving demand for IP telephony • Use QoS to prioritize applications such as IP telephony during congestion and to

help control both delay and jitter within the network.

• Use switches that support at least two queues per port to prioritize voice and data

traffic as either high- or low-priority, based on IEEE 802.1p/Q. The switch supports at least four queues per port.

• Use voice VLAN IDs (VVIDs) to provide separate VLANs for voice traffic.

A growing demand for using existing infrastructure to transport data and voice from a home or office to the Internet or an intranet at higher speeds

You can use the switches and switch stacks to create the following:

• Cost-effective wiring closet (Figure 1-1)—A cost-effective way to connect many users to the wiring

closet is to have a switch stack of up to nine Catalyst 2975 switches. To preserve switch connectivity if one switch in the stack fails, connect the switches as recommended in the hardware installation guide, and enable either cross-stack Etherchannel or cross-stack UplinkFast.

You can have redundant uplink connections, using SFP modules in the switch stack to a Gigabit backbone switch, such as a Catalyst 4500 or Catalyst 3750-12S Gigabit switch. You can also create backup paths by using Fast Ethernet, Gigabit, or EtherChannel links. If one of the redundant connections fails, the other can serve as a backup path. If the Gigabit switch is cluster-capable, you can configure it and the switch stack as a switch cluster to manage them through a single IP address. The Gigabit switch can be connected to a Gigabit server through a 1000BASE-T connection.

Use the Catalyst Long-Reach Ethernet (LRE) switches to provide up to 15 Mb of IP connectivity over existing infrastructure, such as existing telephone lines.

Note LRE is the technology used in the Catalyst 2900 LRE XL and Catalyst 2950

LRE switches. See the documentation sets specific to these switches for LRE information.

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Note Stacking is supported only on Catalyst 2960-S switches running the LAN base image.

Figure 1-1 Cost-Effective Wiring Closet

Catalyst

Gigabit

server

Gigabit Ethernet

multilayer switch

Catalyst 2975

switch stack

250870

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Network Configuration Examples

250871

Catalyst 2975

switch stack

Catalyst 3750 switches

250872

Cisco 2600 router

Catalyst 2975

switch stack

WAN

• Cost-effective Gigabit-to-the-desktop for high-performance workgroups (Figure 1-2)—For

high-speed access to network resources, you can use the Catalyst 2975 switch stack in the access layer to provide Gigabit Ethernet to the desktop. To prevent congestion, use QoS DSCP marking priorities on these switches. For high-speed IP forwarding at the distribution layer, connect the switches in the access layer to a Gigabit multilayer switch with routing capability, such as a Catalyst 3750 switch, or to a router.

The first illustration is of an isolated high-performance workgroup, where the stack is connected to Catalyst 3750 switches in the distribution layer. The second illustration is of a high-performance workgroup in a branch office, where the stack is connected to a router in the distribution layer.

Each switch in this configuration provides users with a dedicated 1-Gb/s connection to network resources. Using SFP modules also provides flexibility in media and distance options through fiber-optic connections.

Figure 1-2 High-Performance Workgroup (Gigabit-to-the-Desktop)

Chapter 1 Overview

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Chapter 1 Overview

250873

Campus

core

Catalyst 6500 switches

Catalyst 2975

switch stack

Access-layer Catalyst switches

Server racks

• Server aggregation (Figure 1-3)—You can use the switches and switch stacks to interconnect groups

of servers, centralizing physical security and administration of your network. For high-speed IP forwarding at the distribution layer, connect the switches in the access layer to multilayer switches with routing capability. The Gigabit interconnections minimize latency in the data flow.

QoS and policing on the switches provide preferential treatment for certain data streams. They segment traffic streams into different paths for processing. Security features on the switch ensure rapid handling of packets.

Fault tolerance from the server racks to the core is achieved through dual homing of servers connected to dual switch stacks, which have redundant Gigabit EtherChannels and cross-stack EtherChannels.

Using dual SFP module uplinks from the switches provides redundant uplinks to the network core. Using SFP modules provides flexibility in media and distance options through fiber-optic connections.

The various lengths of stack cable available, ranging from 0.5 meter to 3 meters provide extended connections to the switch stacks across multiple server racks, for multiple stack aggregation.

Figure 1-3 Server Aggregation

Network Configuration Examples

Small to Medium-Sized Network Using Catalyst 2975 Switches

Figure 1-4 shows a configuration for a network of up to 500 employees. This network uses a

Catalyst 2975 switch stack with high-speed connections to two routers. This ensures connectivity to the Internet, WAN, and mission-critical network resources if one of the routers fails. The switch stack uses cross-stack EtherChannel for loading sharing.

The switches are connected to workstations and local servers. The server farm includes a call-processing server running Cisco CallManager software. Cisco CallManager controls call processing, routing, and Cisco IP Phone features and configuration. The switches are interconnected through Gigabit interfaces.

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Network Configuration Examples

Gigabit servers

101388

Cisco 2600 or

3700 routers

Internet

Cisco IP

phones

Workstations

running

Cisco SoftPhone

software

Aironet wireless

access points

IP IP

Catalyst 2975

switch stack

This network uses VLANs to logically segment the network into well-defined broadcast groups and for security management. Data and multimedia traffic are configured on the same VLAN. Voice traffic from the Cisco IP Phones are configured on separate VVIDs. If data, multimedia, and voice traffic are assigned to the same VLAN, only one VLAN can be configured per wiring closet.

When an end station in one VLAN needs to communicate with an end station in another VLAN, a router or Layer 3 switch routes the traffic to the destination VLAN. In this network, the routers are providing inter-VLAN routing. VLAN access control lists (VLAN maps) on the switch provide intra-VLAN security and prevent unauthorized users from accessing critical areas of the network.

In addition to inter-VLAN routing, the routers provide QoS mechanisms such as DSCP priorities to prioritize the different types of network traffic and to deliver high-priority traffic. If congestion occurs, QoS drops low-priority traffic to allow delivery of high-priority traffic.

Cisco CallManager controls call processing, routing, and Cisco IP Phone features and configuration. Users with workstations running Cisco SoftPhone software can place, receive, and control calls from their PCs. Using Cisco IP Phones, Cisco CallManager software, and Cisco SoftPhone software integrates telephony and IP networks, and the IP network supports both voice and data.

The routers also provide firewall services, Network Address Translation (NAT) services, voice-over-IP (VoIP) gateway services, and WAN and Internet access.

Chapter 1 Overview

Figure 1-4 Collapsed Backbone Configuration

Long-Distance, High-Bandwidth Transport Configuration

1-20

Figure 1-5 shows a configuration for sending 8 Gigabits of data over a single fiber-optic cable. The

Catalyst 2975 switches have coarse wavelength-division multiplexing (CWDM) fiber-optic SFP modules installed. Depending on the CWDM SFP module, data is sent at wavelengths from 1470 to 1610 nm. The higher the wavelength, the farther the transmission can travel. A common wavelength used for long-distance transmissions is 1550 nm.

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Chapter 1 Overview

95750

Access layer

Catalyst 4500

multilayer

switches

Eight

1-Gbps

connections

8 Gbps

Catalyst switches

CWDM

OADM

modules

CWDM

OADM

modules

Aggregation layer

Where to Go Next

The CWDM SFP modules connect to CWDM optical add/drop multiplexer (OADM) modules over distances of up to 393,701 feet (74.5 miles or 120 km). The CWDM OADM modules combine (or multiplex) the different CWDM wavelengths, allowing them to travel simultaneously on the same fiber-optic cable. The CWDM OADM modules on the receiving end separate (or demultiplex) the different wavelengths.

For more information about the CWDM SFP modules and CWDM OADM modules, see the Cisco CWDM GBIC and CWDM SFP Installation Note.

Figure 1-5 Long-Distance, High-Bandwidth Transport Configuration

Where to Go Next

Before configuring the switch, review these sections for startup information:

• Chapter 2, “Using the Command-Line Interface”

• Chapter 3, “Assigning the Switch IP Address and Default Gateway”

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Where to Go Next

Chapter 1 Overview

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CHAP TER

Using the Command-Line Interface

This chapter describes the Cisco IOS command-line interface (CLI) and how to use it to configure your Catalyst 2975 switch.Unless otherwise noted, the term switch refers to a standalone switch and to a switch stack.

It contains these sections:

• Understanding Command Modes, page 2-1

• Understanding the Help System, page 2-3

• Understanding Abbreviated Commands, page 2-4

• Understanding no and default Forms of Commands, page 2-4

• Understanding CLI Error Messages, page 2-5

• Using Configuration Logging, page 2-5

• Using Command History, page 2-6

• Using Editing Features, page 2-7

• Searching and Filtering Output of show and more Commands, page 2-10

• Accessing the CLI, page 2-10

Understanding Command Modes

The Cisco IOS user interface is divided into many different modes. The commands available to you depend on which mode you are currently in. Enter a question mark (?) at the system prompt to obtain a list of commands available for each command mode.

When you start a session on the switch, you begin in user mode, often called user EXEC mode. Only a limited subset of the commands are available in user EXEC mode. For example, most of the user EXEC commands are one-time commands, such as show commands, which show the current configuration status, and clear commands, which clear counters or interfaces. The user EXEC commands are not saved when the switch reboots.

To have access to all commands, you must enter privileged EXEC mode. Normally, you must enter a password to enter privileged EXEC mode. From this mode, you can enter any privileged EXEC command or enter global configuration mode.

Using the configuration modes (global, interface, and line), you can make changes to the running configuration. If you save the configuration, these commands are stored and used when the switch reboots. To access the various configuration modes, you must start at global configuration mode. From global configuration mode, you can enter interface configuration mode and line configuration mode.

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Chapter 2 Using the Command-Line Interface

Understanding Command Modes

Table 2-1 describes the main command modes, how to access each one, the prompt you see in that mode,

and how to exit the mode. The examples in the table use the hostname Switch.

Table 2-1 Command Mode Summary

Mode Access Method Prompt Exit Method About This Mode

User EXEC Begin a session with

your switch.

Privileged EXEC While in user EXEC

mode, enter the enable command.

Global configuration While in privileged

EXEC mode, enter the configure command.

Config-vlan While in global

configuration mode, enter the vlan vlan-id command.

VLAN configuration While in privileged

EXEC mode, enter the vlan database command.

Switch>

Switch#

Switch(config)#

Switch(config-vlan)#

Switch(vlan)#

Enter logout or quit.

Enter disable to exit.

To exit to privileged EXEC mode, enter

exit or end, or press Ctrl-Z.

To exit to global configuration mode, enter the exit command.

To return to privileged EXEC mode, press Ctrl-Z or enter end.

To exit to privileged EXEC mode, enter exit.

Use this mode to

• Change terminal settings.

• Perform basic tests.

• Display system

information.

Use this mode to verify commands that you have entered. Use a password to protect access to this mode.

Use this mode to configure parameters that apply to the entire switch.

Use this mode to configure VLAN parameters. When VTP mode is transparent, you can create extended-range VLANs (VLAN IDs greater than 1005) and save configurations in the switch startup configuration file.

Use this mode to configure VLAN parameters for VLANs 1 to 1005 in the VLAN database.

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Chapter 2 Using the Command-Line Interface

Understanding the Help System

Table 2-1 Command Mode Summary (continued)

Mode Access Method Prompt Exit Method About This Mode

Interface configuration

While in global configuration mode, enter the interface command (with a specific interface).

Line configuration While in global

configuration mode, specify a line with the line vty or line console command.

Switch(config-if)#

Switch(config-line)#

To exit to global configuration mode, enter exit.

To return to privileged EXEC mode, press Ctrl-Z or enter end.

To exit to global configuration mode, enter exit.

To return to privileged EXEC mode, press Ctrl-Z or enter end.

Use this mode to configure parameters for the Ethernet ports.

For information about defining interfaces, see the “Using

Interface Configuration Mode” section on page 12-11.

To configure multiple interfaces with the same parameters, see the

“Configuring a Range of Interfaces” section on page 12-12.

Use this mode to configure parameters for the terminal line.

For more detailed information on the command modes, see the command reference guide for this release.

Understanding the Help System

You can enter a question mark (?) at the system prompt to display a list of commands available for each command mode. You can also obtain a list of associated keywords and arguments for any command, as shown in Table 2- 2 .

Table 2-2 Help Summary

Command Purpose

help Obtain a brief description of the help system in any command mode.

abbreviated-command-entry? Obtain a list of commands that begin with a particular character string.

For example:

Switch# di? dir disable disconnect

abbreviated-command-entry<Tab> Complete a partial command name.

For example:

Switch# sh conf<tab> Switch# show configuration

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Chapter 2 Using the Command-Line Interface

Understanding Abbreviated Commands

Table 2-2 Help Summary (continued)

Command Purpose

? List all commands available for a particular command mode.

For example:

Switch> ?

command ? List the associated keywords for a command.

For example:

Switch> show ?

command keyword ? List the associated arguments for a keyword.

For example:

Switch(config)# cdp holdtime ? <10-255> Length of time (in sec) that receiver must keep this packet

Understanding Abbreviated Commands

You need to enter only enough characters for the switch to recognize the command as unique.

This example shows how to enter the show configuration privileged EXEC command in an abbreviated form:

Switch# show conf

Understanding no and default Forms of Commands

Almost every configuration command also has a no form. In general, use the no form to disable a feature or function or reverse the action of a command. For example, the no shutdown interface configuration command reverses the shutdown of an interface. Use the command without the keyword no to re-enable a disabled feature or to enable a feature that is disabled by default.

Configuration commands can also have a default form. The default form of a command returns the command setting to its default. Most commands are disabled by default, so the default form is the same as the no form. However, some commands are enabled by default and have variables set to certain default values. In these cases, the default command enables the command and sets variables to their default values.

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Understanding CLI Error Messages

Table 2-3 lists some error messages that you might encounter while using the CLI to configure your

switch.

Table 2-3 Common CLI Error Messages

Error Message Meaning How to Get Help

% Ambiguous command: "show con"

% Incomplete command.

% Invalid input detected at ‘^’ marker.

You did not enter enough characters for your switch to recognize the command.

You did not enter all the keywords or values required by this command.

You entered the command incorrectly. The caret (^) marks the point of the error.

Re-enter the command followed by a question mark (?) with a space between the command and the question mark.

The possible keywords that you can enter with the command appear.

Re-enter the command followed by a question mark (?) with a space between the command and the question mark.

The possible keywords that you can enter with the command appear.

Enter a question mark (?) to display all the commands that are available in this command mode.

The possible keywords that you can enter with the command appear.

Understanding CLI Error Messages

Using Configuration Logging

You can log and view changes to the switch configuration. You can use the Configuration Change Logging and Notification feature to track changes on a per-session and per-user basis. The logger tracks each configuration command that is applied, the user who entered the command, the time that the command was entered, and the parser return code for the command. This feature includes a mechanism for asynchronous notification to registered applications whenever the configuration changes. You can choose to have the notifications sent to the syslog.

For more information, see the Configuration Change Notification and Logging feature module:

http://www.cisco.com/en/US/docs/ios/12_3t/12_3t4/feature/guide/gtconlog.html

Note Only CLI or HTTP changes are logged.

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Using Command History

The software provides a history or record of commands that you have entered. The command history feature is particularly useful for recalling long or complex commands or entries, including access lists. You can customize this feature to suit your needs as described in these sections:

• Changing the Command History Buffer Size, page 2-6 (optional)

• Recalling Commands, page 2-6 (optional)

• Disabling the Command History Feature, page 2-7 (optional)

Changing the Command History Buffer Size

By default, the switch records ten command lines in its history buffer. You can alter this number for a current terminal session or for all sessions on a particular line. These procedures are optional.

Beginning in privileged EXEC mode, enter this command to change the number of command lines that the switch records during the current terminal session:

Switch# terminal history [size number-of-lines]

Chapter 2 Using the Command-Line Interface

The range is from 0 to 256.

Beginning in line configuration mode, enter this command to configure the number of command lines the switch records for all sessions on a particular line:

Switch(config-line)# history [size number-of-lines]

The range is from 0 to 256.

Recalling Commands

To recall commands from the history buffer, perform one of the actions listed in Table 2-4. These actions are optional.

Table 2-4 Recalling Commands

Action

Press Ctrl-P or the up arrow key. Recall commands in the history buffer, beginning with the most recent command.

Press Ctrl-N or the down arrow key. Return to more recent commands in the history buffer after recalling commands

show history While in privileged EXEC mode, list the last several commands that you just

1. The arrow keys function only on ANSI-compatible terminals such as VT100s.

Result

Repeat the key sequence to recall successively older commands.

with Ctrl-P or the up arrow key. Repeat the key sequence to recall successively more recent commands.

entered. The number of commands that appear is controlled by the setting of the terminal history global configuration command and the history line configuration command.

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Disabling the Command History Feature

The command history feature is automatically enabled. You can disable it for the current terminal session or for the command line. These procedures are optional.

To disable the feature during the current terminal session, enter the terminal no history privileged EXEC command.

To disable command history for the line, enter the no history line configuration command.

Using Editing Features

This section describes the editing features that can help you manipulate the command line. It contains these sections:

• Enabling and Disabling Editing Features, page 2-7 (optional)

• Editing Commands through Keystrokes, page 2-8 (optional)

• Editing Command Lines that Wrap, page 2-9 (optional)

Using Editing Features

Enabling and Disabling Editing Features

Although enhanced editing mode is automatically enabled, you can disable it, re-enable it, or configure a specific line to have enhanced editing. These procedures are optional.

To globally disable enhanced editing mode, enter this command in line configuration mode:

Switch (config-line)# no editing

To re-enable the enhanced editing mode for the current terminal session, enter this command in privileged EXEC mode:

Switch# terminal editing

To reconfigure a specific line to have enhanced editing mode, enter this command in line configuration mode:

Switch(config-line)# editing

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Using Editing Features

Editing Commands through Keystrokes

Table 2-5 shows the keystrokes that you need to edit command lines. These keystrokes are optional.

Table 2-5 Editing Commands through Keystrokes

Chapter 2 Using the Command-Line Interface

Capability Keystroke

Move around the command line to make changes or corrections.

Press Ctrl-B, or press the left arrow key.

Press Ctrl-F, or press the right arrow key.

Press Ctrl-A. Move the cursor to the beginning of the command line.

Press Ctrl-E. Move the cursor to the end of the command line.

Press Esc B. Move the cursor back one word.

Press Esc F. Move the cursor forward one word.

Press Ctrl-T. Transpose the character to the left of the cursor with the

Recall commands from the buffer and

Press Ctrl-Y. Recall the most recent entry in the buffer. paste them in the command line. The switch provides a buffer with the last ten items that you deleted.

Press Esc Y. Recall the next buffer entry.

Delete entries if you make a mistake or change your mind.

Press the Delete or

Backspace key.

Press Ctrl-D. Delete the character at the cursor.

Press Ctrl-K. Delete all characters from the cursor to the end of the

Press Ctrl-U or Ctrl-X. Delete all characters from the cursor to the beginning of

Press Ctrl-W. Delete the word to the left of the cursor.

Press Esc D. Delete from the cursor to the end of the word.

Capitalize or lowercase words or

Press Esc C. Capitalize at the cursor. capitalize a set of letters.

Press Esc L. Change the word at the cursor to lowercase.

Press Esc U. Capitalize letters from the cursor to the end of the word.

Designate a particular keystroke as

Press Ctrl-V or Esc Q. an executable command, perhaps as a shortcut.

Purpose

Move the cursor back one character.

Move the cursor forward one character.

character located at the cursor.

The buffer contains only the last 10 items that you have deleted or cut. If you press Esc Y more than ten times, you cycle to the first buffer entry.

Erase the character to the left of the cursor.

command line.

the command line.

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Table 2-5 Editing Commands through Keystrokes (continued)

Using Editing Features

Capability Keystroke

Scroll down a line or screen on

Press the Return key. Scroll down one line.

displays that are longer than the terminal screen can display.

Note The More prompt is used for

any output that has more lines than can be displayed on the terminal screen, including show command output. You can use the Return and Space bar keystrokes whenever you see the More prompt.

Press the Space bar. Scroll down one screen.

Redisplay the current command line

Press Ctrl-L or Ctrl-R. Redisplay the current command line. if the switch suddenly sends a message to your screen.

1. The arrow keys function only on ANSI-compatible terminals such as VT100s.

Editing Command Lines that Wrap

Purpose

You can use a wraparound feature for commands that extend beyond a single line on the screen. When the cursor reaches the right margin, the command line shifts ten spaces to the left. You cannot see the first ten characters of the line, but you can scroll back and check the syntax at the beginning of the command. The keystroke actions are optional.

To scroll back to the beginning of the command entry, press Ctrl-B or the left arrow key repeatedly. You can also press Ctrl-A to immediately move to the beginning of the line.

The arrow keys function only on ANSI-compatible terminals such as VT100s.

In this example, the access-list global configuration command entry extends beyond one line. When the cursor first reaches the end of the line, the line is shifted ten spaces to the left and redisplayed. The dollar sign ($) shows that the line has been scrolled to the left. Each time the cursor reaches the end of the line, the line is again shifted ten spaces to the left.

Switch(config)# access-list 101 permit tcp 131.108.2.5 255.255.255.0 131.108.1 Switch(config)# $ 101 permit tcp 131.108.2.5 255.255.255.0 131.108.1.20 255.25 Switch(config)# $t tcp 131.108.2.5 255.255.255.0 131.108.1.20 255.255.255.0 eq Switch(config)# $108.2.5 255.255.255.0 131.108.1.20 255.255.255.0 eq 45

After you complete the entry, press Ctrl-A to check the complete syntax before pressing the Return key to execute the command. The dollar sign ($) appears at the end of the line to show that the line has been scrolled to the right:

Switch(config)# access-list 101 permit tcp 131.108.2.5 255.255.255.0 131.108.1$

The software assumes you have a terminal screen that is 80 columns wide. If you have a width other than that, use the terminal width privileged EXEC command to set the width of your terminal.

Use line wrapping with the command history feature to recall and modify previous complex command entries. For information about recalling previous command entries, see the “Editing Commands through

Keystrokes” section on page 2-8.

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Searching and Filtering Output of show and more Commands

You can search and filter the output for show and more commands. This is useful when you need to sort through large amounts of output or if you want to exclude output that you do not need to see. Using these commands is optional.

To use this functionality, enter a show or more command followed by the pipe character (|), one of the keywords begin, include, or exclude, and an expression that you want to search for or filter out:

command | {begin | include | exclude} regular-expression

Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output are not displayed, but the lines that contain Output appear.

This example shows how to include in the output display only lines where the expression protocol appears:

Switch# show interfaces | include protocol Vlan1 is up, line protocol is up Vlan10 is up, line protocol is down GigabitEthernet1/0/1 is up, line protocol is down GigabitEthernet1/0/2 is up, line protocol is up

Accessing the CLI

You can access the CLI through a console connection, through Telnet, or by using the browser.

You manage the switch stack and the stack member interfaces through the stack master. You cannot manage stack members on an individual switch basis. You can connect to the stack master through the console port of one or more stack members. Be careful with using multiple CLI sessions to the stack master. Commands you enter in one session are not displayed in the other sessions. Therefore, it is possible to lose track of the session from which you entered commands.

If you want to configure a specific stack member port, you must include the stack member number in the CLI command interface notation. For more information about interface notations, see the “Using

Interface Configuration Mode” section on page 12-11.

To debug a specific stack member, you can access it from the stack master by using the session stack-member-number privileged EXEC command. The stack member number is appended to the system prompt. For example, the system prompt for the stack master is a CLI session to a specific stack member.

Accessing the CLI through a Console Connection or through Telnet

Before you can access the CLI, you must connect a terminal or PC to the switch console port and power on the switch, as described in the getting started guide that shipped with your switch. Then, to understand the boot process and the options available for assigning IP information, see Chapter 3, “Assigning the

Switch IP Address and Default Gateway.”

Switch-2# is the prompt in privileged EXEC mode for stack member 2, and where

Switch. Only the show and debug commands are available in

2-10

If your switch is already configured, you can access the CLI through a local console connection or through a remote Telnet session, but your switch must first be configured for this type of access. For more information, see the “Setting a Telnet Password for a Terminal Line” section on page 9-6.

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You can use one of these methods to establish a connection with the switch:

• Connect the switch console port to a management station or dial-up modem. For information about

connecting to the console port, see the switch getting started guide or hardware installation guide.

• Use any Telnet TCP/IP or encrypted Secure Shell (SSH) package from a remote management

station. The switch must have network connectivity with the Telnet or SSH client, and the switch must have an enable secret password configured.

For information about configuring the switch for Telnet access, see the “Setting a Telnet Password

for a Terminal Line” section on page 9-6. The switch supports up to 16 simultaneous Telnet sessions.

Changes made by one Telnet user are reflected in all other Telnet sessions.

For information about configuring the switch for SSH, see the “Configuring the Switch for Secure

Shell” section on page 9-41. The switch supports up to five simultaneous secure SSH sessions.

After you connect through the console port, through a Telnet session or through an SSH session, the user EXEC prompt appears on the management station.

Accessing the CLI

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CHAP TER

Assigning the Switch IP Address and Default Gateway

This chapter describes how to create the initial switch configuration (for example, assigning the IP address and default gateway information) for the Catalyst 2975 switch by using a variety of automatic and manual methods. It also describes how to modify the switch startup configuration. Unless otherwise noted, the term switch refers to a standalone switch and to a switch stack.

Note For complete syntax and usage information for the commands used in this chapter, see the command

reference for this release and the Cisco IOS IP Command Reference, Volume 1 of 3: Addressing and Services from the Cisco.com page under Documentation > Cisco IOS Software > 12.2 Mainline >

Command References.

This chapter consists of these sections:

• Understanding the Boot Process, page 3-2

• Assigning Switch Information, page 3-3

• Checking and Saving the Running Configuration, page 3-16

• Modifying the Startup Configuration, page 3-18

• Scheduling a Reload of the Software Image, page 3-23

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Understanding the Boot Process

To start your switch, you need to follow the procedures in the Getting Started Guide or the hardware installation guide for installing and powering on the switch and for setting up the initial switch configuration (IP address, subnet mask, default gateway, secret and Telnet passwords, and so forth).

The normal boot process involves the operation of the boot loader software, which performs these activities:

• Performs low-level CPU initialization. It initializes the CPU registers, which control where physical

memory is mapped, its quantity, its speed, and so forth.

• Performs power-on self-test (POST) for the CPU subsystem. It tests the CPU DRAM and the portion

of the flash device that makes up the flash file system.

• Loads a default operating system software image into memory and boots up the switch.

The boot loader provides access to the flash file system before the operating system is loaded. Normally, the boot loader is used only to load, uncompress, and launch the operating system. After the boot loader gives the operating system control of the CPU, the boot loader is not active until the next system reset or power-on.

The boot loader also provides trap-door access into the system if the operating system has problems serious enough that it cannot be used. The trap-door mechanism provides enough access to the system so that if it is necessary, you can format the flash file system, reinstall the operating system software image by using the Xmodem Protocol, recover from a lost or forgotten password, and finally restart the operating system. For more information, see the “Recovering from a Software Failure” section on

page 38-2 and the “Recovering from a Lost or Forgotten Password” section on page 38-3.

Chapter 3 Assigning the Switch IP Address and Default Gateway

Note You can disable password recovery. For more information, see the “Disabling Password Recovery”

section on page 9-5.

Before you can assign switch information, make sure you have connected a PC or terminal to the console port, and configured the PC or terminal-emulation software baud rate and character format to match these of the switch console port:

• Baud rate default is 9600.

• Data bits default is 8.

Note If the data bits option is set to 8, set the parity option to none.

• Stop bits default is 1.

• Parity settings default is none.

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Assigning Switch Information

You can assign IP information through the switch setup program, through a DHCP server, or manually.

Use the switch setup program if you want to be prompted for specific IP information. With this program, you can also configure a hostname and an enable secret password. It gives you the option of assigning a Telnet password (to provide security during remote management) and configuring your switch as a command or member switch of a cluster or as a standalone switch. For more information about the setup program, see the hardware installation guide.

The switch stack is managed through a single IP address. The IP address is a system-level setting and is not specific to the stack master or to any other stack member. You can still manage the stack through the same IP address even if you remove the stack master or any other stack member from the stack, provided there is IP connectivity.

Note Stack members retain their IP address when you remove them from a switch stack. To avoid a conflict

by having two devices with the same IP address in your network, change the IP address of the switch that you removed from the switch stack

Assigning Switch Information

Use a DHCP server for centralized control and automatic assignment of IP information after the server is configured.

Note If you are using DHCP, do not respond to any of the questions in the setup program until the switch

receives the dynamically assigned IP address and reads the configuration file.

If you are an experienced user familiar with the switch configuration steps, manually configure the switch. Otherwise, use the setup program described previously.

• Default Switch Information, page 3-3

• Understanding DHCP-Based Autoconfiguration, page 3-4

• Manually Assigning IP Information, page 3-15

Default Switch Information

Table 3-1 shows the default switch information.

Table 3-1 Default Switch Information

Feature Default Setting

IP address and subnet mask No IP address or subnet mask are defined.

Default gateway No default gateway is defined.

Enable secret password No password is defined.

Hostname The factory-assigned default hostname is Switch.

Telnet password No password is defined.

Cluster command switch functionality Disabled.

Cluster name No cluster name is defined.

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Switch A

DHCPACK (unicast)

DHCPREQUEST (broadcast)

DHCPOFFER (unicast)

DHCPDISCOVER (broadcast)

DHCP server

Assigning Switch Information

Understanding DHCP-Based Autoconfiguration

DHCP provides configuration information to Internet hosts and internetworking devices. This protocol consists of two components: one for delivering configuration parameters from a DHCP server to a device and a mechanism for allocating network addresses to devices. DHCP is built on a client-server model, in which designated DHCP servers allocate network addresses and deliver configuration parameters to dynamically configured devices. The switch can act as both a DHCP client and a DHCP server.

During DHCP-based autoconfiguration, your switch (DHCP client) is automatically configured at startup with IP address information and a configuration file.

With DHCP-based autoconfiguration, no DHCP client-side configuration is needed on your switch. However, you need to configure the DHCP server for various lease options associated with IP addresses. If you are using DHCP to relay the configuration file location on the network, you might also need to configure a Trivial File Transfer Protocol (TFTP) server and a Domain Name System (DNS) server.

Note We recommend a redundant connection between a switch stack and the DHCP, DNS, and TFTP servers.

This is to help ensure that these servers remain accessible in case one of the connected stack members is removed from the switch stack.

The DHCP server for your switch can be on the same LAN or on a different LAN than the switch. If the DHCP server is running on a different LAN, you should configure a DHCP relay device between your switch and the DHCP server. A relay device forwards broadcast traffic between two directly connected LANs. A router does not forward broadcast packets, but it forwards packets based on the destination IP address in the received packet.

DHCP-based autoconfiguration replaces the BOOTP client functionality on your switch.

DHCP Client Request Process

When you boot up your switch, the DHCP client is invoked and requests configuration information from a DHCP server when the configuration file is not present on the switch. If the configuration file is present and the configuration includes the ip address dhcp interface configuration command on specific routed interfaces, the DHCP client is invoked and requests the IP address information for those interfaces.

Figure 3-1 shows the sequence of messages that are exchanged between the DHCP client and the DHCP

server.

Figure 3-1 DHCP Client and Server Message Exchange

3-4

The client, Switch A, broadcasts a DHCPDISCOVER message to locate a DHCP server. The DHCP server offers configuration parameters (such as an IP address, subnet mask, gateway IP address, DNS IP address, a lease for the IP address, and so forth) to the client in a DHCPOFFER unicast message.

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In a DHCPREQUEST broadcast message, the client returns a formal request for the offered configuration information to the DHCP server. The formal request is broadcast so that all other DHCP servers that received the DHCPDISCOVER broadcast message from the client can reclaim the IP addresses that they offered to the client.

The DHCP server confirms that the IP address has been allocated to the client by returning a DHCPACK unicast message to the client. With this message, the client and server are bound, and the client uses configuration information received from the server. The amount of information the switch receives depends on how you configure the DHCP server. For more information, see the “Configuring the TFTP

Server” section on page 3-8.

If the configuration parameters sent to the client in the DHCPOFFER unicast message are invalid (a configuration error exists), the client returns a DHCPDECLINE broadcast message to the DHCP server.

The DHCP server sends the client a DHCPNAK denial broadcast message, which means that the offered configuration parameters have not been assigned, that an error has occurred during the negotiation of the parameters, or that the client has been slow in responding to the DHCPOFFER message. (The DHCP server assigned the parameters to another client.)

A DHCP client might receive offers from multiple DHCP or BOOTP servers and can accept any of the offers; however, the client usually accepts the first offer it receives. The offer from the DHCP server is not a guarantee that the IP address is allocated to the switch. However, the server usually reserves the address until the client has had a chance to formally request the address. If the switch accepts replies from a BOOTP server and configures itself, the switch broadcasts, instead of unicasts, TFTP requests to obtain the switch configuration file.

Assigning Switch Information

The DHCP hostname option allows a group of switches to obtain hostnames and a standard configuration from the central management DHCP server. A client (switch) includes in its DCHPDISCOVER message an option 12 field used to request a hostname and other configuration parameters from the DHCP server. The configuration files on all clients are identical except for their DHCP-obtained hostnames.

If a client has a default hostname (the hostname name global configuration command is not configured or the no hostname global configuration command is entered to remove the hostname), the DHCP hostname option is not included in the packet when you enter the ip address dhcp interface configuration command. In this case, if the client receives the DCHP hostname option from the DHCP interaction while acquiring an IP address for an interface, the client accepts the DHCP hostname option and sets the flag to show that the system now has a hostname configured.

Understanding DHCP-based Autoconfiguration and Image Update

You can use the DHCP image upgrade features to configure a DHCP server to download both a new image and a new configuration file to one or more switches in a network. This helps ensure that each new switch added to a network receives the same image and configuration.

There are two types of DHCP image upgrades: DHCP autoconfiguration and DHCP auto-image update.

DHCP Autoconfiguration

DHCP autoconfiguration downloads a configuration file to one or more switches in your network from a DHCP server. The downloaded configuration file becomes the running configuration of the switch. It does not over write the bootup configuration saved in the flash, until you reload the switch.

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DHCP Auto-Image Update

You can use DHCP auto-image upgrade with DHCP autoconfiguration to download both a configuration and a new image to one or more switches in your network. The switch (or switches) downloading the new configuration and the new image can be blank (or only have a default factory configuration loaded).

If the new configuration is downloaded to a switch that already has a configuration, the downloaded configuration is appended to the configuration file stored on the switch. (Any existing configuration is not overwritten by the downloaded one.)

Note To enable a DHCP auto-image update on the switch, the TFTP server where the image and configuration

files are located must be configured with the correct option 67 (the configuration filename), option 66 (the DHCP server hostname) option 150 (the TFTP server address), and option 125 (description of the file) settings.

For procedures to configure the switch as a DHCP server, see the “Configuring DHCP-Based

Autoconfiguration” section on page 3-7 and the “Configuring DHCP” section of the “IP addressing and

Services” section of the Cisco IOS IP Configuration Guide, Release 12.2.

Chapter 3 Assigning the Switch IP Address and Default Gateway

After you install the switch in your network, the auto-image update feature starts. The downloaded configuration file is saved in the running configuration of the switch, and the new image is downloaded and installed on the switch. When you reboot the switch, the configuration is stored in the saved configuration on the switch.

Limitations and Restrictions

These are the limitations:

• The DHCP-based autoconfiguration with a saved configuration process stops if there is not at least

one Layer 3 interface in an up state without an assigned IP address in the network.

• Unless you configure a timeout, the DHCP-based autoconfiguration with a saved configuration

feature tries indefinitely to download an IP address.

• The auto-install process stops if a configuration file cannot be downloaded or it the configuration

file is corrupted.

Note The configuration file that is downloaded from TFTP is merged with the existing configuration in the

running configuration but is not saved in the NVRAM unless you enter the write memory or copy running-configuration startup-configuration privileged EXEC command. Note that if the

downloaded configuration is saved to the startup configuration, the feature is not triggered during subsequent system restarts.

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Configuring DHCP-Based Autoconfiguration

These sections contain this configuration information:

• DHCP Server Configuration Guidelines, page 3-7

• Configuring the TFTP Server, page 3-8

• Configuring the DNS, page 3-8

• Configuring the Relay Device, page 3-9

• Obtaining Configuration Files, page 3-9

• Example Configuration, page 3-10

DHCP Server Configuration Guidelines

Follow these guidelines if you are configuring a device as a DHCP server:

You should configure the DHCP server with reserved leases that are bound to each switch by the switch hardware address.

If you want the switch to receive IP address information, you must configure the DHCP server with these lease options:

Assigning Switch Information

• IP address of the client (required)

• Subnet mask of the client (required)

• Router IP address (default gateway address to be used by the switch) (required)

• DNS server IP address (optional)

If you want the switch to receive the configuration file from a TFTP server, you must configure the DHCP server with these lease options:

• TFTP server name (required)

• Boot filename (the name of the configuration file that the client needs) (recommended)

• Hostname (optional)

Depending on the settings of the DHCP server, the switch can receive IP address information, the configuration file, or both.

If you do not configure the DHCP server with the lease options described previously, it replies to client requests with only those parameters that are configured. If the IP address and the subnet mask are not in the reply, the switch is not configured. If the router IP address or the TFTP server name are not found, the switch might send broadcast, instead of unicast, TFTP requests. Unavailability of other lease options does not affect autoconfiguration.

The switch can act as a DHCP server. By default, the Cisco IOS DHCP server and relay agent features are enabled on your switch but are not configured. These features are not operational. If your DHCP server is a Cisco device, for additional information about configuring DHCP, see the “Configuring DHCP” section of the “IP Addressing and Services” section of the Cisco IOS IP Configuration Guide from the Cisco.com page under Documentation > Cisco IOS Software > 12.2 Mainline > Configuration Guides.

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DHCP Server and Switch Stacks

The DHCP binding database is managed on the stack master. When a new stack master is assigned, the new master downloads the saved binding database from the TFTP server. If the stack master fails, all unsaved bindings are lost. The IP addresses associated with the lost bindings are released. You should configure an automatic backup by using the ip dhcp database url [timeout seconds | write-delay seconds] global configuration command.

When a stack merge occurs, the stack master that becomes a stack member loses all of the DHCP lease bindings. With a stack partition, the new master in the partition acts as a new DHCP server without any of the existing DHCP lease bindings.

For more information about the switch stack, see Chapter 6, “Managing Switch Stacks.”

Configuring the TFTP Server

Based on the DHCP server configuration, the switch attempts to download one or more configuration files from the TFTP server. If you configured the DHCP server to respond to the switch with all the options required for IP connectivity to the TFTP server, and if you configured the DHCP server with a TFTP server name, address, and configuration filename, the switch attempts to download the specified configuration file from the specified TFTP server.

If you did not specify the configuration filename, the TFTP server, or if the configuration file could not be downloaded, the switch attempts to download a configuration file by using various combinations of filenames and TFTP server addresses. The files include the specified configuration filename (if any) and these files: network-config, cisconet.cfg, hostname.config, or hostname.cfg, where hostname is the switch’s current hostname. The TFTP server addresses used include the specified TFTP server address (if any) and the broadcast address (255.255.255.255).

For the switch to successfully download a configuration file, the TFTP server must contain one or more configuration files in its base directory. The files can include these files:

Chapter 3 Assigning the Switch IP Address and Default Gateway

• The configuration file named in the DHCP reply (the actual switch configuration file).

• The network-confg or the cisconet.cfg file (known as the default configuration files).

• The router-confg or the ciscortr.cfg file (These files contain commands common to all switches.

If you specify the TFTP server name in the DHCP server-lease database, you must also configure the TFTP server name-to-IP-address mapping in the DNS-server database.

If the TFTP server to be used is on a different LAN from the switch, or if it is to be accessed by the switch through the broadcast address (which occurs if the DHCP server response does not contain all the required information described previously), a relay must be configured to forward the TFTP packets to the TFTP server. For more information, see the “Configuring the Relay Device” section on page 3-9. The preferred solution is to configure the DHCP server with all the required information.

Configuring the DNS

The DHCP server uses the DNS server to resolve the TFTP server name to an IP address. You must configure the TFTP server name-to-IP address map on the DNS server. The TFTP server contains the configuration files for the switch.

You can configure the IP addresses of the DNS servers in the lease database of the DHCP server from where the DHCP replies will retrieve them. You can enter up to two DNS server IP addresses in the lease database.

Normally, if the DHCP and TFTP servers are properly configured, these files are not accessed.)

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Switch

(DHCP client)

Cisco router

(Relay)

49068

DHCP server TFTP server DNS server

20.0.0.2 20.0.0.3

20.0.0.1

10.0.0.2

10.0.0.1

20.0.0.4

The DNS server can be on the same or on a different LAN as the switch. If it is on a different LAN, the switch must be able to access it through a router.

Configuring the Relay Device

You must configure a relay device, also referred to as a relay agent, when a switch sends broadcast packets that require a response from a host on a different LAN. Examples of broadcast packets that the switch might send are DHCP, DNS, and in some cases, TFTP packets. You must configure this relay device to forward received broadcast packets on an interface to the destination host.

If the relay device is a Cisco router, enable IP routing (ip routing global configuration command), and configure helper addresses by using the ip helper-address interface configuration command.

For example, in Figure 3-2, configure the router interfaces as follows:

On interface 10.0.0.2:

router(config-if)# ip helper-address 20.0.0.2 router(config-if)# ip helper-address 20.0.0.3 router(config-if)# ip helper-address 20.0.0.4

On interface 20.0.0.1

router(config-if)# ip helper-address 10.0.0.1

Assigning Switch Information

Obtaining Configuration Files

Figure 3-2 Relay Device Used in Autoconfiguration

Depending on the availability of the IP address and the configuration filename in the DHCP reserved lease, the switch obtains its configuration information in these ways:

• The IP address and the configuration filename is reserved for the switch and provided in the DHCP

reply (one-file read method).

The switch receives its IP address, subnet mask, TFTP server address, and the configuration filename from the DHCP server. The switch sends a unicast message to the TFTP server to retrieve the named configuration file from the base directory of the server and upon receipt, it completes its boot-up process.

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Switch 1

00e0.9f1e.2001

Cisco router

111394

Switch 2

00e0.9f1e.2002

Switch 3

00e0.9f1e.2003

DHCP server DNS server TFTP server

(tftpserver)

10.0.0.1

10.0.0.10

10.0.0.2 10.0.0.3

Switch 4

00e0.9f1e.2004

• The IP address and the configuration filename is reserved for the switch, but the TFTP server

• Only the IP address is reserved for the switch and provided in the DHCP reply. The configuration

Chapter 3 Assigning the Switch IP Address and Default Gateway

address is not provided in the DHCP reply (one-file read method).

The switch receives its IP address, subnet mask, and the configuration filename from the DHCP server. The switch sends a broadcast message to a TFTP server to retrieve the named configuration file from the base directory of the server, and upon receipt, it completes its boot-up process.

filename is not provided (two-file read method).

The switch receives its IP address, subnet mask, and the TFTP server address from the DHCP server. The switch sends a unicast message to the TFTP server to retrieve the network-confg or cisconet.cfg default configuration file. (If the network-confg file cannot be read, the switch reads the cisconet.cfg file.)

The default configuration file contains the hostnames-to-IP-address mapping for the switch. The switch fills its host table with the information in the file and obtains its hostname. If the hostname is not found in the file, the switch uses the hostname in the DHCP reply. If the hostname is not specified in the DHCP reply, the switch uses the default Switch as its hostname.

After obtaining its hostname from the default configuration file or the DHCP reply, the switch reads the configuration file that has the same name as its hostname (hostname-confg or hostname.cfg, depending on whether network-confg or cisconet.cfg was read earlier) from the TFTP server. If the cisconet.cfg file is read, the filename of the host is truncated to eight characters.

If the switch cannot read the network-confg, cisconet.cfg, or the hostname file, it reads the router-confg file. If the switch cannot read the router-confg file, it reads the ciscortr.cfg file.

Note The switch broadcasts TFTP server requests if the TFTP server is not obtained from the DHCP replies,

if all attempts to read the configuration file through unicast transmissions fail, or if the TFTP server name cannot be resolved to an IP address.

Example Configuration

Figure 3-3 shows a sample network for retrieving IP information by using DHCP-based

autoconfiguration.

Figure 3-3 DHCP-Based Autoconfiguration Network Example

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Assigning Switch Information

Table 3-2 shows the configuration of the reserved leases on the DHCP server.

Table 3-2 DHCP Server Configuration

Switch A Switch B Switch C Switch D

Binding key (hardware address) 00e0.9f1e.2001 00e0.9f1e.2002 00e0.9f1e.2003 00e0.9f1e.2004

IP address 10.0.0.21 10.0.0.22 10.0.0.23 10.0.0.24

Subnet mask 255.255.255.0 255.255.255.0 255.255.255.0 255.255.255.0

Router address 10.0.0.10 10.0.0.10 10.0.0.10 10.0.0.10

DNS server address 10.0.0.2 10.0.0.2 10.0.0.2 10.0.0.2

TFTP server name tftpserver or

10.0.0.3

Boot filename (configuration file)

switcha-confg switchb-confg switchc-confg switchd-confg

(optional)

Hostname (optional) switcha switchb switchc switchd

tftpserver or

10.0.0.3

tftpserver or

10.0.0.3

tftpserver or

10.0.0.3

DNS Server Configuration

The DNS server maps the TFTP server name tftpserver to IP address 10.0.0.3.

TFTP Server Configuration (on UNIX)

The TFTP server base directory is set to /tftpserver/work/. This directory contains the network-confg file used in the two-file read method. This file contains the hostname to be assigned to the switch based on its IP address. The base directory also contains a configuration file for each switch (switcha-confg, switchb-confg, and so forth) as shown in this display:

prompt> cd /tftpserver/work/ prompt> ls network-confg switcha-confg switchb-confg switchc-confg switchd-confg prompt> cat network-confg ip host switcha 10.0.0.21 ip host switchb 10.0.0.22 ip host switchc 10.0.0.23 ip host switchd 10.0.0.24

DHCP Client Configuration

No configuration file is present on Switch A through Switch D.

Configuration Explanation

In Figure 3-3, Switch A reads its configuration file as follows:

• It obtains its IP address 10.0.0.21 from the DHCP server.

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• If no configuration filename is given in the DHCP server reply, Switch A reads the network-confg

file from the base directory of the TFTP server.

• It adds the contents of the network-confg file to its host table.

• It reads its host table by indexing its IP address 10.0.0.21 to its hostname (switcha).

• It reads the configuration file that corresponds to its hostname; for example, it reads switch1-confg

from the TFTP server.

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Assigning Switch Information

Switches B through D retrieve their configuration files and IP addresses in the same way.

Configuring the DHCP Auto Configuration and Image Update Features

Using DHCP to download a new image and a new configuration to a switch requires that you configure at least two switches: One switch acts as a DHCP and TFTP server. The client switch is configured to download either a new configuration file or a new configuration file and a new image file.

Configuring DHCP Autoconfiguration (Only Configuration File)

Beginning in privileged EXEC mode, follow these steps to configure DHCP autoconfiguration of the TFTP and DHCP settings on a new switch to download a new configuration file.

Command Purpose

Step 1

Step 2

Step 3

Step 4

configure terminal Enter global configuration mode.

ip dhcp poolname Create a name for the DHCP Server address pool, and enter DHCP

pool configuration mode.

bootfile filename Specify the name of the configuration file that is used as a boot image.

network network-number mask

prefix-length

Specify the subnet network number and mask of the DHCP address pool.

Step 5

Step 6

Step 7

Step 8

Step 9

Step 10

Step 11

Step 12

Step 13

Note The prefix length specifies the number of bits that comprise

the address prefix. The prefix is an alternative way of specifying the network mask of the client. The prefix length must be preceded by a forward slash (/).

default-router address Specify the IP address of the default router for a DHCP client.

option 150 address Specify the IP address of the TFTP server.

exit Return to global configuration mode.

tftp-server flash:filename.text Specify the configuration file on the TFTP server.

interface interface-id Specify the address of the client that will receive the configuration

file.

no switchport Put the interface into Layer 3 mode.

ip address address mask Specify the IP address and mask for the interface.

end Return to privileged EXEC mode.

copy running-config startup-config (Optional) Save your entries in the configuration file.

This example shows how to configure a switch as a DHCP server so that it will download a configuration file:

Switch# configure terminal Switch(config)# ip dhcp pool pool1 Switch(dhcp-config)# network 10.10.10.0 255.255.255.0 Switch(dhcp-config)# bootfile config-boot.text Switch(dhcp-config)# default-router 10.10.10.1 Switch(dhcp-config)# option 150 10.10.10.1 Switch(dhcp-config)# exit Switch(config)# tftp-server flash:config-boot.text Switch(config)# interface gigabitethernet1/0/4

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Switch(config-if)# no switchport Switch(config-if)# ip address 10.10.10.1 255.255.255.0 Switch(config-if)# end

Configuring DHCP Auto-Image Update (Configuration File and Image)

Beginning in privileged EXEC mode, follow these steps to configure DHCP autoconfiguration to configure TFTP and DHCP settings on a new switch to download a new image and a new configuration file.

Note Before following the steps in this table, you must create a text file (for example, autoinstall_dhcp) that

will be uploaded to the switch. In the text file, put the name of the image that you want to download. This image must be a tar and not a bin file.

Command Purpose

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Step 7

Step 8

Step 9

Step 10

Step 11

Step 12

Step 13

Step 14

Step 15

Step 16

Step 17

Step 18

configure terminal Enter global configuration mode.

ip dhcp pool name Create a name for the DHCP server address pool and enter DHCP pool

configuration mode.

bootfile filename Specify the name of the file that is used as a boot image.

network network-number mask

prefix-length

Specify the subnet network number and mask of the DHCP address pool.

Note The prefix length specifies the number of bits that comprise the

address prefix. The prefix is an alternative way of specifying the network mask of the client. The prefix length must be preceded by a forward slash (/).

default-router address Specify the IP address of the default router for a DHCP client.

option 150 address Specify the IP address of the TFTP server.

option 125 hex Specify the path to the text file that describes the path to the image file.

copy tftp flash filename.txt Upload the text file to the switch.

copy tftp flash imagename.tar Upload the tar file for the new image to the switch.

exit Return to global configuration mode.

tftp-server flash:config.text Specify the Cisco IOS configuration file on the TFTP server.

tftp-server flash:imagename.tar Specify the image name on the TFTP server.

tftp-server flash:filename.txt Specify the text file that contains the name of the image file to download

interface interface-id Specify the address of the client that will receive the configuration file.

no switchport Put the interface into Layer 3 mode.

ip address address mask Specify the IP address and mask for the interface.

end Return to privileged EXEC mode.

copy running-config startup-config (Optional) Save your entries in the configuration file.

Assigning Switch Information

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Assigning Switch Information

This example shows how to configure a switch as a DHCP server so it downloads a configuration file:

Switch# config terminal Switch(config)# ip dhcp pool pool1 Switch(dhcp-config)# network 10.10.10.0 255.255.255.0 Switch(dhcp-config)# bootfile config-boot.text Switch(dhcp-config)# default-router 10.10.10.1 Switch(dhcp-config)# option 150 10.10.10.1 Switch(dhcp-config)# option 125 hex

0000.0009.0a05.08661.7574.6f69.6e73.7461.6c6c.5f64.686370

Switch(dhcp-config)# exit Switch(config)# tftp-server flash:config-boot.text Switch(config)# tftp-server flash:c2975-lanbase-tar.122-46.SE.tar Switch(config)# tftp-server flash:boot-config.text Switch(config)# tftp-server flash: autoinstall_dhcp Switch(config)# interface gigabitethernet1/0/4 Switch(config-if)# no switchport Switch(config-if)# ip address 10.10.10.1 255.255.255.0 Switch(config-if)# end

Configuring the Client

Beginning in privileged EXEC mode, follow these steps to configure a switch to download a configuration file and new image from a DHCP server:

Chapter 3 Assigning the Switch IP Address and Default Gateway

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Command Purpose

configure terminal Enter global configuration mode.

boot host dhcp Enable autoconfiguration with a saved configuration.

boot host retry timeout timeout-value (Optional) Set the amount of time the system tries to

download a configuration file.

Note If you do not set a timeout the system will

indefinitely try to obtain an IP address from the DHCP server.

banner config-save ^C warning-message ^C (Optional) Create warning messages to be displayed

when you try to save the configuration file to NVRAM.

end Return to privileged EXEC mode.

show boot Verify the configuration.

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This example uses a Layer 3 SVI interface on VLAN 99 to enable DHCP-based autoconfiguration with a saved configuration:

Switch# configure terminal Switch(conf)# boot host dhcp Switch(conf)# boot host retry timeout 300 Switch(conf)# banner config-save ^C Caution - Saving Configuration File to NVRAM May Cause

You to No longer Automatically Download Configuration Files at Reboot^C

Switch(config)# vlan 99 Switch(config-vlan)# interface vlan 99 Switch(config-if)# no shutdown Switch(config-if)# end Switch# show boot BOOT path-list: Config file: flash:/config.text Private Config file: flash:/private-config.text Enable Break: no Manual Boot: no HELPER path-list: NVRAM/Config file buffer size: 32768 Timeout for Config Download: 300 seconds Config Download via DHCP: enabled (next boot: enabled) Switch#

Assigning Switch Information

Note You should only configure and enable the Layer 3 interface. Do not assign an IP address or DHCP-based

autoconfiguration with a saved configuration.

Manually Assigning IP Information

Beginning in privileged EXEC mode, follow these steps to manually assign IP information to multiple switched virtual interfaces (SVIs):

Command Purpose

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

configure terminal Enter global configuration mode.

interface vlan vlan-id Enter interface configuration mode, and enter the VLAN to which the IP

information is assigned. The VLAN range is 1 to 4094.

ip address ip-address subnet-mask Enter the IP address and subnet mask.

exit Return to global configuration mode.

ip default-gateway ip-address Enter the IP address of the next-hop router interface that is directly

connected to the switch where a default gateway is being configured. The default gateway receives IP packets with unresolved destination IP addresses from the switch.

Once the default gateway is configured, the switch has connectivity to the remote networks with which a host needs to communicate.

Note When your switch is configured to route with IP, it does not need

end Return to privileged EXEC mode.

to have a default gateway set.

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Checking and Saving the Running Configuration

Command Purpose

Step 7

Step 8

Step 9

show interfaces vlan vlan-id Verify the configured IP address.

show ip redirects Verify the configured default gateway.

copy running-config startup-config (Optional) Save your entries in the configuration file.

To remove the switch IP address, use the no ip address interface configuration command. If you are removing the address through a Telnet session, your connection to the switch will be lost. To remove the default gateway address, use the no ip default-gateway global configuration command.

For information on setting the switch system name, protecting access to privileged EXEC commands, and setting time and calendar services, see Chapter 7, “Administering the Switch.”

Checking and Saving the Running Configuration

You can check the configuration settings that you entered or changes that you made by entering this privileged EXEC command:

Switch# show running-config Building configuration...

Current configuration: 1363 bytes ! version 12.2 no service pad service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname Stack1 ! enable secret 5 $1$ej9.$DMUvAUnZOAmvmgqBEzIxE0 ! . <output truncated> . interface gigabitethernet6/0/1 ip address 172.20.137.50 255.255.255.0 ! interface gigabitethernet6/0/2 mvr type source

...! interface VLAN1 ip address 172.20.137.50 255.255.255.0 no ip directed-broadcast ! ip default-gateway 172.20.137.1 ! ! snmp-server community private RW snmp-server community public RO snmp-server community private@es0 RW snmp-server community public@es0 RO snmp-server chassis-id 0x12 ! end

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To store the configuration or changes you have made to your startup configuration in flash memory, enter this privileged EXEC command:

Switch# copy running-config startup-config Destination filename [startup-config]? Building configuration...

This command saves the configuration settings that you made. If you fail to do this, your configuration will be lost the next time you reload the system. To display information stored in the NVRAM section of flash memory, use the show startup-config or more startup-config privileged EXEC command.

For more information about alternative locations from which to copy the configuration file, see

Appendix B, “Working with the Cisco IOS File System, Configuration Files, and Software Images.”

Configuring the NVRAM Buffer Size

The default NVRAM buffer size is 512 KB. In some cases, the configuration file might be too large to save to NVRAM. Typically, this occurs when you have many switches in a switch stack. You can configure the size of the NVRAM buffer to support larger configuration files. The new NVRAM buffer size is synced to all current and new member switches.

Checking and Saving the Running Configuration

Step 1

Step 2

Step 3

Step 4

Note After you configure the NVRAM buffer size, reload the switch or switch stack.

When you add a switch to a stack and the NVRAM size differs, the new switch syncs with the stack and reloads automatically.

Beginning in privileged EXEC mode, follow these steps to configure the NVRAM buffer size:

Command Purpose

configure terminal Enter global configuration mode.

boot buffersize size Configure the NVRAM buffersize in KB. The valid range

for size is from 4096 to 1048576.

end Return to privileged EXEC mode.

show boot Verify the configuration.

This example shows how to configure the NVRAM buffer size:

Switch# configure terminal Enter configuration commands, one per line. End with CNTL/Z. Switch(config)# boot buffersize 524288 Switch(config)# end Switch# show boot BOOT path-list : Config file : flash:/config.text Private Config file : flash:/private-config.text Enable Break : no Manual Boot : no HELPER path-list : Auto upgrade : yes Auto upgrade path : NVRAM/Config file buffer size: 524288

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Modifying the Startup Configuration

Timeout for Config Download: 300 seconds Config Download via DHCP: enabled (next boot: enabled) Switch#

Modifying the Startup Configuration

These sections describe how to modify the switch startup configuration:

• Default Boot Configuration, page 3-18

• Automatically Downloading a Configuration File, page 3-18

• Booting Manually, page 3-19

• Booting a Specific Software Image, page 3-20

• Controlling Environment Variables, page 3-21

See also “Stack Configuration Files” section on page 6-13 and Appendix B, “Working with the Cisco

IOS File System, Configuration Files, and Software Images,” for information about switch stack

configuration files.

Chapter 3 Assigning the Switch IP Address and Default Gateway

Default Boot Configuration

Table 3-3 shows the default boot-up configuration.

Table 3-3 Default Boot Configuration

Feature Default Setting

Operating system software image The switch attempts to automatically boot up the system using information in the

BOOT environment variable. If the variable is not set, the switch attempts to load and execute the first executable image it can by performing a recursive, depth-first search throughout the flash file system.

The Cisco IOS image is stored in a directory that has the same name as the image file (excluding the .bin extension).

In a depth-first search of a directory, each encountered subdirectory is completely searched before continuing the search in the original directory.

Configuration file Configured switches use the config.text file stored on the system board in flash

memory.

A new switch has no configuration file.

Automatically Downloading a Configuration File

3-18

You can automatically download a configuration file to your switch by using the DHCP-based autoconfiguration feature. For more information, see the “Understanding DHCP-Based

Autoconfiguration” section on page 3-4.

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Modifying the Startup Configuration

Specifying the Filename to Read and Write the System Configuration

By default, the Cisco IOS software uses the file config.text to read and write a nonvolatile copy of the system configuration. However, you can specify a different filename, which will be loaded during the next boot-up cycle.

Note This command only works properly from a standalone switch.

Beginning in privileged EXEC mode, follow these steps to specify a different configuration filename:

Command Purpose

Step 1

Step 2

configure terminal Enter global configuration mode.

boot config-file flash:/file-url Specify the configuration file to load during the next boot-up

cycle.

For file-url, specify the path (directory) and the configuration filename.

Step 3

Step 4

Step 5

end Return to privileged EXEC mode.

show boot Verify your entries.

copy running-config startup-config (Optional) Save your entries in the configuration file.

To return to the default setting, use the no boot config-file global configuration command.

Booting Manually

By default, the switch automatically boots up; however, you can configure it to manually boot up.

Note This command only works properly from a standalone switch.

Beginning in privileged EXEC mode, follow these steps to configure the switch to manually boot up during the next boot cycle:

Command Purpose

Step 1

Step 2

Step 3

configure terminal Enter global configuration mode.

boot manual Enable the switch to manually boot up during the next boot cycle.

end Return to privileged EXEC mode.

Filenames and directory names are case sensitive.

The boot config-file global configuration command changes the setting of the CONFIG_FILE environment variable.

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Command Purpose

Step 4

Step 5

show boot Verify your entries.

copy running-config startup-config (Optional) Save your entries in the configuration file.

To disable manual booting, use the no boot manual global configuration command.

Chapter 3 Assigning the Switch IP Address and Default Gateway

The boot manual global command changes the setting of the MANUAL_BOOT environment variable.

The next time you reboot the system, the switch is in boot loader mode, shown by the switch: prompt. To boot up the system, use the boot filesystem:/file-url boot loader command.

• For filesystem:, use flash: for the system board flash device.

• For file-url, specify the path (directory) and the name of the

bootable image.

Filenames and directory names are case sensitive.

Booting a Specific Software Image

By default, the switch attempts to automatically boot up the system using information in the BOOT environment variable. If this variable is not set, the switch attempts to load and execute the first executable image it can by performing a recursive, depth-first search throughout the flash file system. In a depth-first search of a directory, each encountered subdirectory is completely searched before continuing the search in the original directory. However, you can specify a specific image to boot up.

Beginning in privileged EXEC mode, follow these steps to configure the switch to boot a specific image during the next boot cycle:

Command Purpose

Step 1

Step 2

Step 3

configure terminal Enter global configuration mode.

boot system filesystem:/file-url Configure the switch to boot a specific image in flash memory during the

next boot cycle.

• For filesystem:, use flash: for the system board flash device.

• For file-url, specify the path (directory) and the name of the bootable

If you enter this command on a stack master, the specified software image is loaded only on the stack master during the next boot cycle.

Filenames and directory names are case sensitive.

boot system switch {number | all} (Optional) Specify the switch members on which the system image is

loaded during the next boot cycle:

image.

Step 4

3-20

• Use number to specify a stack member. (Specify only one stack

member.)

• Use all to specify all stack members.

end Return to privileged EXEC mode.

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Command Purpose

Step 5

show boot Verify your entries.

The boot system global command changes the setting of the BOOT environment variable.

During the next boot cycle, the switch attempts to automatically boot up the system using information in the BOOT environment variable.

Step 6

copy running-config startup-config (Optional) Save your entries in the configuration file.

To return to the default setting, use the no boot system global configuration command.

Controlling Environment Variables

With a normally operating switch, you enter the boot loader mode only through a switch console connection configured for 9600 b/s. Unplug the switch power cord, and press the switch Mode button while reconnecting the power cord. You can release the Mode button a second or two after the LED above port 1 turns off. Then the boot loader switch: prompt appears.

Modifying the Startup Configuration

The switch boot loader software provides support for nonvolatile environment variables, which can be used to control how the boot loader, or any other software running on the system, behaves. Boot loader environment variables are similar to environment variables that can be set on UNIX or DOS systems.

Environment variables that have values are stored in flash memory outside of the flash file system.

Each line in these files contains an environment variable name and an equal sign followed by the value of the variable. A variable has no value if it is not listed in this file; it has a value if it is listed in the file even if the value is a null string. A variable that is set to a null string (for example, “ ”) is a variable with a value. Many environment variables are predefined and have default values.

Environment variables store two kinds of data:

• Data that controls code, which does not read the Cisco IOS configuration file. For example, the

name of a boot loader helper file, which extends or patches the functionality of the boot loader can be stored as an environment variable.

• Data that controls code, which is responsible for reading the Cisco IOS configuration file. For

example, the name of the Cisco IOS configuration file can be stored as an environment variable.

You can change the settings of the environment variables by accessing the boot loader or by using Cisco IOS commands. Under normal circumstances, it is not necessary to alter the setting of the environment variables.

Note For complete syntax and usage information for the boot loader commands and environment variables,

see the command reference for this release.

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Modifying the Startup Configuration

Table 3-4 describes the function of the most common environment variables.

Table 3-4 Environment Variables

Variable Boot Loader Command Cisco IOS Global Configuration Command

BOOT set BOOT filesystem:/file-url ...

A semicolon-separated list of executable files to try to load and execute when automatically booting. If the BOOT environment variable is not set, the system attempts to load and execute the first executable image it can find by using a recursive, depth-first search through the flash file system. If the BOOT variable is set but the specified images cannot be loaded, the system attempts to boot the first bootable file that it can find in the flash file system.

MANUAL_BOOT set MANUAL_BOOT yes

Decides whether the switch automatically or manually boots up.

Valid values are 1, yes, 0, and no. If it is set to no or 0, the boot loader attempts to automatically boot up the system. If it is set to anything else, you must manually boot up the switch from the boot loader mode.

CONFIG_FILE set CONFIG_FILE flash:/file-url

boot system {filesystem:/file-url ...| switch

{number | all}}

Specifies the Cisco IOS image to load during the next boot cycle and the stack members on which the image is loaded. This command changes the setting of the BOOT environment variable.

boot manual

Enables manually booting up the switch during the next boot cycle and changes the setting of the MANUAL_BOOT environment variable.

The next time you reboot the system, the switch is in boot loader mode. To boot up the system, use the boot flash:filesystem:/file-url boot loader command, and specify the name of the bootable image.

boot config-file flash:/file-url

Changes the filename that Cisco IOS uses to read and write a nonvolatile copy of the system configuration.

SWITCH_NUMBER set SWITCH_NUMBER stack-member-number

Changes the member number of a stack member.

SWITCH_PRIORITY set SWITCH_PRIORITY

stack-member-number

Changes the priority value of a stack member.

Specifies the filename that Cisco IOS uses to read and write a nonvolatile copy of the system configuration. This command changes the CONFIG_FILE environment variable.

switch current-stack-member-number renumber new-stack-member-number

Changes the member number of a stack member.

switch stack-member-number priority priority-number

Changes the priority value of a stack member.

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Scheduling a Reload of the Software Image

You can schedule a reload of the software image to occur on the switch at a later time (for example, late at night or during the weekend when the switch is used less), or you can synchronize a reload network-wide (for example, to perform a software upgrade on all switches in the network).

Note A scheduled reload must take place within approximately 24 days.

Configuring a Scheduled Reload

To configure your switch to reload the software image at a later time, use one of these commands in privileged EXEC mode:

• reload in [hh:]mm [text]

This command schedules a reload of the software to take affect in the specified minutes or hours and minutes. The reload must take place within approximately 24 days. You can specify the reason for the reload in a string up to 255 characters in length.

Scheduling a Reload of the Software Image

To reload a specific switch in a switch stack, use the reload slot stack-member-number privileged EXEC command.

• reload at hh:mm [month day | day month] [text]

This command schedules a reload of the software to take place at the specified time (using a 24-hour clock). If you specify the month and day, the reload is scheduled to take place at the specified time and date. If you do not specify the month and day, the reload takes place at the specified time on the current day (if the specified time is later than the current time) or on the next day (if the specified time is earlier than the current time). Specifying 00:00 schedules the reload for midnight.

Note Use the at keyword only if the switch system clock has been set (through Network Time

Protocol (NTP), the hardware calendar, or manually). The time is relative to the configured time zone on the switch. To schedule reloads across several switches to occur simultaneously, the time on each switch must be synchronized with NTP.

The reload command halts the system. If the system is not set to manually boot up, it reboots itself. Use the reload command after you save the switch configuration information to the startup configuration (copy running-config startup-config).

If your switch is configured for manual booting, do not reload it from a virtual terminal. This restriction prevents the switch from entering the boot loader mode and thereby taking it from the remote user’s control.

If you modify your configuration file, the switch prompts you to save the configuration before reloading. During the save operation, the system requests whether you want to proceed with the save if the CONFIG_FILE environment variable points to a startup configuration file that no longer exists. If you proceed in this situation, the system enters setup mode upon reload.

This example shows how to reload the software on the switch on the current day at 7:30 p.m:

Switch# reload at 19:30 Reload scheduled for 19:30:00 UTC Wed Jun 5 1996 (in 2 hours and 25 minutes) Proceed with reload? [confirm]

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Scheduling a Reload of the Software Image

This example shows how to reload the software on the switch at a future time:

Switch# reload at 02:00 jun 20 Reload scheduled for 02:00:00 UTC Thu Jun 20 1996 (in 344 hours and 53 minutes) Proceed with reload? [confirm]

To cancel a previously scheduled reload, use the reload cancel privileged EXEC command.

Displaying Scheduled Reload Information

To display information about a previously scheduled reload or to find out if a reload has been scheduled on the switch, use the show reload privileged EXEC command.

It displays reload information including the time the reload is scheduled to occur and the reason for the reload (if it was specified when the reload was scheduled).

Chapter 3 Assigning the Switch IP Address and Default Gateway

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CHAP TER

Configuring Cisco IOS Configuration Engine

This chapter describes how to configure the feature on the Catalyst 2975 switches. Unless otherwise noted, the term switch refers to a standalone switch and a switch stack.

Note For complete configuration information for the Cisco Configuration Engine, go to

http://www.cisco.com/en/US/products/sw/netmgtsw/ps4617/tsd_products_support_series_home.html

For complete syntax and usage information for the commands used in this chapter, go to the Cisco IOS

Network Management Command Reference, Release 12.4:

http://www.cisco.com/en/US/docs/ios/netmgmt/command/reference/nm_book.html

• Understanding Cisco Configuration Engine Software, page 4-1

• Understanding Cisco IOS Agents, page 4-5

• Configuring Cisco IOS Agents, page 4-6

• Displaying CNS Configuration, page 4-13

Understanding Cisco Configuration Engine Software

The Cisco Configuration Engine is network management software that acts as a configuration service for automating the deployment and management of network devices and services (see Figure 4-1). Each Configuration Engine manages a group of Cisco devices (switches and routers) and the services that they deliver, storing their configurations and delivering them as needed. The Configuration Engine automates initial configurations and configuration updates by generating device-specific configuration changes, sending them to the device, executing the configuration change, and logging the results.

The Configuration Engine supports standalone and server modes and has these CNS components:

• Configuration service (web server, file manager, and namespace mapping server)

• Event service (event gateway)

• Data service directory (data models and schema)

In standalone mode, the Configuration Engine supports an embedded Directory Service. In this mode, no external directory or other data store is required. In server mode, the Configuration Engine supports the use of a user-defined external directory.

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Understanding Cisco Configuration Engine Software

Configuration

engine

Service provider network

Order entry

configuration management

Data service directory

Configuration server

Event service

Web-based user interface

141327

Figure 4-1 Configuration Engine Architectural Overview

Chapter 4 Configuring Cisco IOS Configuration Engine

Configuration Service, page 4-2

•

• Event Service, page 4-3

• What You Should Know About the CNS IDs and Device Hostnames, page 4-3

Configuration Service

The Configuration Service is the core component of the Cisco Configuration Engine. It consists of a configuration server that works with Cisco IOS CNS agents on the switch. The Configuration Service delivers device and service configurations to the switch for initial configuration and mass reconfiguration by logical groups. Switches receive their initial configuration from the Configuration Service when they start up on the network for the first time.

The Configuration Service uses the CNS Event Service to send and receive configuration change events and to send success and failure notifications.

The configuration server is a web server that uses configuration templates and the device-specific configuration information stored in the embedded (standalone mode) or remote (server mode) directory.

Configuration templates are text files containing static configuration information in the form of CLI commands. In the templates, variables are specified using Lightweight Directory Access Protocol (LDAP) URLs that reference the device-specific configuration information stored in a directory.

The Cisco IOS agent can perform a syntax check on received configuration files and publish events to show the success or failure of the syntax check. The configuration agent can either apply configurations immediately or delay the application until receipt of a synchronization event from the configuration server.

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Cisco Catalyst 2975 Software Configuration Manual

Catalyst 2975 Switch Software Configuration Guide

CONTENTS

Audience

Purpose

Preface

Conventions

Related Publications

Obtaining Documentation, Obtaining Support, and Security Guidelines

Features

Overview

Ease-of-Deployment and Ease-of-Use Features

Performance Features

Management Options

Manageability Features

Availability and Redundancy Features

VLAN Features

Security Features

QoS and CoS Features

Layer 3 Features

Power over Ethernet Features

Monitoring Features

Default Settings After Initial Switch Configuration

Network Configuration Examples

Design Concepts for Using the Switch

Small to Medium-Sized Network Using Catalyst 2975 Switches

Long-Distance, High-Bandwidth Transport Configuration

Where to Go Next

Using the Command-Line Interface

Understanding Command Modes

Understanding the Help System

Understanding Abbreviated Commands

Understanding no and default Forms of Commands

Understanding CLI Error Messages

Using Configuration Logging

Using Command History

Changing the Command History Buffer Size

Recalling Commands

Disabling the Command History Feature

Using Editing Features

Enabling and Disabling Editing Features

Editing Commands through Keystrokes

Editing Command Lines that Wrap

Searching and Filtering Output of show and more Commands

Accessing the CLI

Accessing the CLI through a Console Connection or through Telnet

Assigning the Switch IP Address and Default Gateway

Understanding the Boot Process

Assigning Switch Information

Default Switch Information

Understanding DHCP-Based Autoconfiguration

DHCP Client Request Process

Understanding DHCP-based Autoconfiguration and Image Update

DHCP Autoconfiguration

DHCP Auto-Image Update

Limitations and Restrictions

Configuring DHCP-Based Autoconfiguration

DHCP Server Configuration Guidelines

Configuring the TFTP Server

Configuring the DNS

Configuring the Relay Device

Obtaining Configuration Files

Example Configuration

Configuring the DHCP Auto Configuration and Image Update Features

Configuring DHCP Autoconfiguration (Only Configuration File)

Configuring DHCP Auto-Image Update (Configuration File and Image)

Configuring the Client

Manually Assigning IP Information

Checking and Saving the Running Configuration

Configuring the NVRAM Buffer Size

Modifying the Startup Configuration

Default Boot Configuration

Automatically Downloading a Configuration File

Specifying the Filename to Read and Write the System Configuration

Booting Manually

Booting a Specific Software Image

Controlling Environment Variables

Scheduling a Reload of the Software Image

Configuring a Scheduled Reload

Displaying Scheduled Reload Information