Cisco Systems Cat2960-Xr Switch WSC2960XR48TSI User Manual

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Catalyst 2960 Switch

Software Configuration Guide

Cisco IOS Release 12.2(25)FX

September 2005

Corporate Headquarters

Cisco Systems, Inc. 170 West Tasman Drive

San Jose, CA 95134-1706USAhttp://www.cisco.com Tel: 408526-4000

800 553-NETS(6387) Fax: 408526-4100

Customer Order Number: DOC-7816881=

Text Part Number: 78-16881-01

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-NAMEDSUPPLIERS 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.

CCSP, CCVP, the Cisco Square Bridge logo, Follow Me Browsing, and StackWise are trademarks of Cisco Systems, Inc.; Changing the Way We Work, Live, Play, and Learn, and iQuick Study are service marks of Cisco Systems, Inc.; and Access Registrar, Aironet, ASIST, BPX, Catalyst, CCDA, CCDP, CCIE, CCIP, CCNA, CCNP, Cisco, the Cisco Certified Internetwork Expert logo, Cisco IOS, Cisco Press, Cisco Systems, Cisco Systems Capital, the Cisco Systems logo, Cisco Unity, Empowering the Internet Generation, Enterprise/Solver, EtherChannel, EtherFast, EtherSwitch, Fast Step, FormShare, GigaDrive, GigaStack, HomeLink, Internet Quotient, IOS, IP/TV, iQ Expertise, the iQ logo, iQ Net Readiness Scorecard, LightStream, Linksys, MeetingPlace, MGX, the Networkers logo, Networking Academy, Network Registrar, Packet, PIX,Post-Routing,Pre-Routing,ProConnect, RateMUX, ScriptShare, SlideCast, SMARTnet, StrataView Plus, TeleRouter, The Fastest Way to Increase Your Internet Quotient, and TransPath are registered trademarks of Cisco Systems, Inc. and/or its affiliates in the United States and certain other countries.

All other trademarks mentioned in this document or Website 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. (0502R)

Catalyst 2960 Switch Software Configuration Guide

Copyright © 2005 Cisco Systems, Inc. All rights reserved.

C O N T E N T S

 

 

Preface xxvii

 

 

 

 

 

 

 

 

 

 

 

 

Audience xxvii

 

 

 

 

 

 

 

 

 

 

 

Purpose

xxvii

 

 

 

 

 

 

 

 

 

 

 

Conventions

xxviii

 

 

 

 

 

 

 

 

 

 

 

Related Publications

xxviii

 

 

 

 

 

 

 

 

 

Obtaining Documentation

xxix

 

 

 

 

 

 

 

 

Cisco.com

xxix

 

 

 

 

 

 

 

 

 

 

 

Product Documentation DVD

xxx

 

 

 

 

 

 

 

Ordering Documentation

xxx

 

 

 

 

 

 

 

Documentation Feedback

xxx

 

 

 

 

 

 

 

 

Cisco Product Security Overview

xxxi

 

 

 

 

 

 

 

Reporting Security Problems in Cisco Products

xxxi

 

 

Obtaining Technical Assistance

xxxii

 

 

 

 

 

 

 

Cisco Technical Support & Documentation Website xxxii

 

 

Submitting a Service Request

xxxii

 

 

 

 

 

 

 

Definitions of Service Request Severity

xxxiii

 

 

 

 

 

 

Obtaining Additional Publications and Information

xxxiii

 

Overview

 

 

 

 

 

 

 

 

 

 

 

C H A P T E R 1

1-1

 

 

 

 

 

 

 

 

 

 

 

 

Features

1-1

 

 

 

 

 

 

 

 

 

 

 

 

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

1-2

 

 

 

 

 

Performance Features

 

1-3

 

 

 

 

 

 

 

 

Management Options

 

1-3

 

 

 

 

 

 

 

 

Manageability Features

1-4

 

 

 

 

 

 

 

 

Availability Features

1-5

 

 

 

 

 

 

 

 

VLAN Features

1-6

 

 

 

 

 

 

 

 

 

 

Security Features

1-6

 

 

 

 

 

 

 

 

 

 

QoS and CoS Features

 

1-7

 

 

 

 

 

 

 

 

Monitoring Features

1-8

 

 

 

 

 

 

 

 

Default Settings After Initial Switch Configuration

1-8

 

 

 

 

 

Network Configuration Examples

1-11

 

 

 

 

 

 

 

Design Concepts for Using the Switch

1-11

 

 

 

 

 

 

Small to Medium-Sized Network Using Catalyst 2960 Switches 1-14

 

 

Long-Distance, High-Bandwidth Transport Configuration 1-15

 

 

 

 

 

 

 

 

 

Catalyst 2960 Switch Software Configuration Guide

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Contents

 

 

 

 

 

Where to Go Next

1-16

 

 

 

 

 

 

 

 

 

 

Using the Command-Line Interface

 

 

 

 

 

C H A P T E R 2

 

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

 

 

 

 

 

 

 

 

 

Using Command History

2-5

 

 

 

 

 

 

 

 

 

 

 

 

Changing the Command History Buffer Size

2-5

 

 

 

 

 

 

 

Recalling Commands

2-6

 

 

 

 

 

 

 

 

 

 

 

 

Disabling the Command History Feature

2-6

 

 

 

 

 

 

 

 

Using Editing Features

2-6

 

 

 

 

 

 

 

 

 

 

 

 

Enabling and Disabling Editing Features

2-7

 

 

 

 

 

 

 

 

Editing Commands through Keystrokes

2-7

 

 

 

 

 

 

 

 

Editing Command Lines that Wrap

2-8

 

 

 

 

 

 

 

 

 

Searching and Filtering Output of show and more Commands 2-9

 

 

 

 

 

Accessing the CLI

2-9

 

 

 

 

 

 

 

 

 

 

 

 

 

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

 

 

Assigning the Switch IP Address and Default Gateway 3-1

C H A P T E R 3

 

 

 

 

 

 

Understanding the Boot Process

 

3-1

 

 

 

 

 

 

 

 

 

 

Assigning Switch Information

3-2

 

 

 

 

 

 

 

 

 

 

Default Switch Information

 

3-3

 

 

 

 

 

 

 

 

 

 

Understanding DHCP-Based Autoconfiguration

3-3

 

 

 

 

 

 

DHCP Client Request Process

3-4

 

 

 

 

 

 

 

 

 

Configuring DHCP-Based Autoconfiguration

3-5

 

 

 

 

 

 

DHCP Server Configuration Guidelines

3-5

 

 

 

 

 

 

 

Configuring the TFTP Server

3-5

 

 

 

 

 

 

 

 

 

Configuring the DNS

3-6

 

 

 

 

 

 

 

 

 

 

Configuring the Relay Device

3-6

 

 

 

 

 

 

 

 

 

Obtaining Configuration Files

3-7

 

 

 

 

 

 

 

 

 

Example Configuration

 

3-8

 

 

 

 

 

 

 

 

 

 

Manually Assigning IP Information

3-9

 

 

 

 

 

 

 

 

 

Checking and Saving the Running Configuration

3-10

 

 

 

 

 

 

Modifying the Startup Configuration

3-11

 

 

 

 

 

 

 

 

 

Default Boot Configuration

3-12

 

 

 

 

 

 

 

 

 

 

Automatically Downloading a Configuration File

3-12

 

 

 

 

 

Catalyst 2960 Switch Software Configuration Guide

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Contents

 

 

Specifying the Filename to Read and Write the System Configuration 3-12

 

 

Booting Manually

3-13

 

 

 

 

 

 

 

 

 

 

Booting a Specific Software Image

3-13

 

 

 

 

 

 

Controlling Environment Variables

3-14

 

 

 

 

 

 

 

Scheduling a Reload of the Software Image

3-15

 

 

 

 

 

 

Configuring a Scheduled Reload

3-16

 

 

 

 

 

 

 

Displaying Scheduled Reload Information

3-17

 

 

 

 

 

Configuring IE2100 CNS Agents

 

 

 

 

 

 

 

 

C H A P T E R 4

4-1

 

 

 

 

 

 

 

 

 

Understanding IE2100 Series Configuration Registrar Software 4-1

 

 

CNS Configuration Service

4-2

 

 

 

 

 

 

 

 

 

CNS Event Service

4-3

 

 

 

 

 

 

 

 

 

 

NameSpace Mapper

4-3

 

 

 

 

 

 

 

 

 

What You Should Know About ConfigID, DeviceID, and Hostname 4-3

 

 

ConfigID

4-3

 

 

 

 

 

 

 

 

 

 

 

DeviceID

4-4

 

 

 

 

 

 

 

 

 

 

 

Hostname and DeviceID 4-4

 

 

 

 

 

 

 

 

Using Hostname, DeviceID, and ConfigID 4-4

 

 

 

 

 

 

Understanding CNS Embedded Agents

4-5

 

 

 

 

 

 

 

Initial Configuration

4-5

 

 

 

 

 

 

 

 

 

 

Incremental (Partial) Configuration

4-6

 

 

 

 

 

 

 

Synchronized Configuration

4-6

 

 

 

 

 

 

 

 

 

Configuring CNS Embedded Agents

4-6

 

 

 

 

 

 

 

 

Enabling Automated CNS Configuration

4-6

 

 

 

 

 

 

Enabling the CNS Event Agent

4-8

 

 

 

 

 

 

 

 

Enabling the CNS Configuration Agent

4-9

 

 

 

 

 

 

Enabling an Initial Configuration

4-9

 

 

 

 

 

 

Enabling a Partial Configuration

4-12

 

 

 

 

 

 

Displaying CNS Configuration

4-13

 

 

 

 

 

 

 

 

Clustering Switches

 

 

 

 

 

 

 

 

 

 

C H A P T E R 5

5-1

 

 

 

 

 

 

 

 

 

 

 

Understanding Switch Clusters

5-1

 

 

 

 

 

 

 

 

 

Clustering Overview

5-1

 

 

 

 

 

 

 

 

 

 

Cluster Command Switch Characteristics

5-2

 

 

 

 

 

 

Standby Cluster Command Switch Characteristics

5-2

 

 

 

 

 

Candidate Switch and Cluster Member Switch Characteristics 5-3

 

 

Using the CLI to Manage Switch Clusters

5-3

 

 

 

 

 

 

Catalyst 1900 and Catalyst 2820 CLI Considerations

5-4

 

 

 

 

 

Using SNMP to Manage Switch Clusters

5-4

 

 

 

 

 

 

 

 

 

 

 

 

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Contents

C H A P T E R 6

Administering the Switch

6-1

 

 

 

 

 

 

 

 

 

 

 

 

 

Managing the System Time and Date

 

6-1

 

 

 

 

 

 

 

 

 

Understanding the System Clock

 

6-2

 

 

 

 

 

 

 

 

 

Understanding Network Time Protocol

6-2

 

 

 

 

 

 

 

 

Configuring NTP

6-4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Default NTP Configuration

6-4

 

 

 

 

 

 

 

 

 

 

Configuring NTP Authentication

6-5

 

 

 

 

 

 

 

 

 

Configuring NTP Associations

6-6

 

 

 

 

 

 

 

 

 

Configuring NTP Broadcast Service

6-7

 

 

 

 

 

 

 

Configuring NTP Access Restrictions

6-8

 

 

 

 

 

 

 

Configuring the Source IP Address for NTP Packets

6-10

 

 

 

 

 

Displaying the NTP Configuration

6-11

 

 

 

 

 

 

 

 

Configuring Time and Date Manually

6-11

 

 

 

 

 

 

 

 

Setting the System Clock

 

6-11

 

 

 

 

 

 

 

 

 

 

Displaying the Time and Date Configuration

6-12

 

 

 

 

 

 

Configuring the Time Zone

 

6-12

 

 

 

 

 

 

 

 

 

 

Configuring Summer Time (Daylight Saving Time)

6-13

 

 

 

 

 

Configuring a System Name and Prompt

6-14

 

 

 

 

 

 

 

 

 

Default System Name and Prompt Configuration

6-15

 

 

 

 

 

 

Configuring a System Name

6-15

 

 

 

 

 

 

 

 

 

 

Understanding DNS

6-15

 

 

 

 

 

 

 

 

 

 

 

 

 

Default DNS Configuration

 

6-16

 

 

 

 

 

 

 

 

 

 

Setting Up DNS

6-16

 

 

 

 

 

 

 

 

 

 

 

 

 

Displaying the DNS Configuration

6-17

 

 

 

 

 

 

 

 

Creating a Banner

6-17

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Default Banner Configuration

6-17

 

 

 

 

 

 

 

 

 

 

Configuring a Message-of-the-Day Login Banner

6-18

 

 

 

 

 

 

Configuring a Login Banner

6-18

 

 

 

 

 

 

 

 

 

 

 

Managing the MAC Address Table

6-19

 

 

 

 

 

 

 

 

 

 

Building the Address Table

6-20

 

 

 

 

 

 

 

 

 

 

 

MAC Addresses and VLANs

6-20

 

 

 

 

 

 

 

 

 

 

Default MAC Address Table Configuration

 

6-20

 

 

 

 

 

 

 

Changing the Address Aging Time

6-21

 

 

 

 

 

 

 

 

 

Removing Dynamic Address Entries

6-21

 

 

 

 

 

 

 

 

 

Configuring MAC Address Notification Traps

6-21

 

 

 

 

 

 

Adding and Removing Static Address Entries

6-23

 

 

 

 

 

 

Configuring Unicast MAC Address Filtering

6-24

 

 

 

 

 

 

 

Displaying Address Table Entries

6-25

 

 

 

 

 

 

 

 

 

Managing the ARP Table

6-26

 

 

 

 

 

 

 

 

 

 

 

 

 

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Contents

C H A P T E R 7

Configuring SDM Templates

7-1

 

 

 

 

 

Understanding the SDM Templates 7-1

 

 

 

 

Configuring the Switch SDM Template 7-2

 

 

 

Default SDM Template

7-2

 

 

 

 

 

SDM Template Configuration Guidelines

7-2

 

Setting the SDM Template

7-2

 

 

 

 

Displaying the SDM Templates

7-3

 

 

 

 

Configuring Switch-Based Authentication

 

 

C H A P T E R 8

8-1

 

 

Preventing Unauthorized Access to Your Switch

 

8-1

 

Protecting Access to Privileged EXEC Commands

8-2

 

Default Password and Privilege Level Configuration 8-2

 

Setting or Changing a Static Enable Password

8-3

 

Protecting Enable and Enable Secret Passwords with Encryption 8-3

 

Disabling Password Recovery

8-5

 

 

 

 

Setting a Telnet Password for a Terminal Line

8-6

 

Configuring Username and Password Pairs

8-7

 

Configuring Multiple Privilege Levels

8-8

 

 

 

Setting the Privilege Level for a Command

8-8

 

 

 

 

Changing the Default Privilege Level for Lines 8-9

 

Logging into and Exiting a Privilege Level

8-10

 

 

 

 

Controlling Switch Access with TACACS+

8-10

 

 

 

 

 

Understanding TACACS+ 8-10

 

 

 

 

 

 

 

TACACS+ Operation

8-12

 

 

 

 

 

 

 

Configuring TACACS+

8-12

 

 

 

 

 

 

 

Default TACACS+ Configuration

8-13

 

 

 

 

 

Identifying the TACACS+ Server Host and Setting the Authentication Key 8-13

 

Configuring TACACS+ Login Authentication

8-14

 

 

 

 

Configuring TACACS+ Authorization for Privileged EXEC Access and Network Services 8-16

 

Starting TACACS+ Accounting

8-17

 

 

 

 

 

 

Displaying the TACACS+ Configuration

8-17

 

 

 

 

 

Controlling Switch Access with RADIUS

8-17

 

 

 

 

 

Understanding RADIUS

8-18

 

 

 

 

 

 

 

RADIUS Operation 8-19

 

 

 

 

 

 

 

Configuring RADIUS

8-20

 

 

 

 

 

 

 

Default RADIUS Configuration

8-20

 

 

 

 

 

 

Identifying the RADIUS Server Host

8-20

 

 

 

 

 

Configuring RADIUS Login Authentication

8-23

 

 

 

 

Defining AAA Server Groups 8-25

 

 

 

 

 

 

 

 

 

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Contents

 

 

 

 

 

Configuring RADIUS Authorization for User Privileged Access and Network Services 8-27

 

 

 

 

 

Starting RADIUS Accounting

8-28

 

 

 

 

 

 

 

 

 

 

Configuring Settings for All RADIUS Servers

8-29

 

 

 

 

 

 

 

Configuring the Switch to Use Vendor-Specific RADIUS Attributes 8-29

 

 

 

 

 

Configuring the Switch for Vendor-Proprietary RADIUS Server Communication 8-30

 

 

 

 

 

Displaying the RADIUS Configuration

8-31

 

 

 

 

 

 

 

 

 

Configuring the Switch for Local Authentication and Authorization

8-32

 

 

 

 

 

 

Configuring the Switch for Secure Shell

8-33

 

 

 

 

 

 

 

 

 

Understanding SSH

8-33

 

 

 

 

 

 

 

 

 

 

 

 

 

SSH Servers, Integrated Clients, and Supported Versions

8-33

 

 

 

 

 

 

Limitations

8-34

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Configuring SSH

8-34

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Configuration Guidelines

8-34

 

 

 

 

 

 

 

 

 

 

 

Setting Up the Switch to Run SSH

 

8-35

 

 

 

 

 

 

 

 

 

Configuring the SSH Server

 

8-36

 

 

 

 

 

 

 

 

 

 

 

Displaying the SSH Configuration and Status

8-36

 

 

 

 

 

 

 

Configuring the Switch for Secure Socket Layer HTTP

8-37

 

 

 

 

 

 

 

Understanding Secure HTTP Servers and Clients

8-37

 

 

 

 

 

 

 

Certificate Authority Trustpoints

8-37

 

 

 

 

 

 

 

 

 

CipherSuites

8-39

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Configuring Secure HTTP Servers and Clients

8-39

 

 

 

 

 

 

 

Default SSL Configuration

8-39

 

 

 

 

 

 

 

 

 

 

 

SSL Configuration Guidelines

8-40

 

 

 

 

 

 

 

 

 

 

Configuring a CA Trustpoint

 

8-40

 

 

 

 

 

 

 

 

 

 

 

Configuring the Secure HTTP Server

8-41

 

 

 

 

 

 

 

 

 

Configuring the Secure HTTP Client

8-42

 

 

 

 

 

 

 

 

 

Displaying Secure HTTP Server and Client Status

8-43

 

 

 

 

Configuring IEEE 802.1x Port-Based Authentication

 

 

 

C H A P T E R 9

 

9-1

 

 

 

 

 

 

 

Understanding IEEE 802.1x Port-Based Authentication

9-1

 

 

 

 

 

 

 

Device Roles

9-2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Authentication Initiation and Message Exchange

9-3

 

 

 

 

 

 

 

Ports in Authorized and Unauthorized States

9-4

 

 

 

 

 

 

 

 

IEEE 802.1x Accounting

9-5

 

 

 

 

 

 

 

 

 

 

 

 

 

IEEE 802.1x Accounting Attribute-Value Pairs

9-5

 

 

 

 

 

 

 

IEEE 802.1x Host Mode

9-6

 

 

 

 

 

 

 

 

 

 

 

 

 

Using IEEE 802.1x with Port Security

9-7

 

 

 

 

 

 

 

 

 

Using IEEE 802.1x with Voice VLAN Ports

9-8

 

 

 

 

 

 

 

 

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Using IEEE 802.1x with VLAN Assignment

9-8

 

 

 

 

 

 

 

 

Using IEEE 802.1x with Guest VLAN

9-10

 

 

 

 

 

 

 

 

Configuring IEEE 802.1x Authentication

9-10

 

 

 

 

 

 

 

 

 

Default IEEE 802.1x Configuration

9-11

 

 

 

 

 

 

 

 

 

IEEE 802.1x Configuration Guidelines

9-12

 

 

 

 

 

 

 

 

Configuring IEEE 802.1x Authentication

 

9-12

 

 

 

 

 

 

 

 

Configuring the Switch-to-RADIUS-Server Communication

9-14

 

 

 

 

 

Configuring Periodic Re-Authentication

 

9-15

 

 

 

 

 

 

 

 

Manually Re-Authenticating a Client Connected to a Port

9-15

 

 

 

 

 

Changing the Quiet Period

9-16

 

 

 

 

 

 

 

 

 

 

 

Changing the Switch-to-Client Retransmission Time

9-16

 

 

 

 

 

 

Setting the Switch-to-Client Frame-Retransmission Number

9-17

 

 

 

 

 

Setting the Re-Authentication Number

9-17

 

 

 

 

 

 

 

 

Configuring the Host Mode

9-18

 

 

 

 

 

 

 

 

 

 

 

Configuring a Guest VLAN

9-19

 

 

 

 

 

 

 

 

 

 

 

Resetting the IEEE 802.1x Configuration to the Default Values 9-20

 

 

Configuring IEEE 802.1x Accounting

9-21

 

 

 

 

 

 

 

 

Displaying IEEE 802.1x Statistics and Status

 

9-22

 

 

 

 

 

 

 

Configuring Interface Characteristics

 

 

 

 

 

 

 

 

 

C H A P T E R 10

10-1

 

 

 

 

 

 

 

 

 

 

Understanding Interface Types

10-1

 

 

 

 

 

 

 

 

 

 

 

Port-Based VLANs

10-2

 

 

 

 

 

 

 

 

 

 

 

 

Switch Ports 10-2

 

 

 

 

 

 

 

 

 

 

 

 

Access Ports

10-2

 

 

 

 

 

 

 

 

 

 

 

 

Trunk Ports

10-3

 

 

 

 

 

 

 

 

 

 

 

 

EtherChannel Port Groups

10-3

 

 

 

 

 

 

 

 

 

 

 

Dual-Purpose Uplink Ports

10-4

 

 

 

 

 

 

 

 

 

 

 

Connecting Interfaces 10-4

 

 

 

 

 

 

 

 

 

 

 

 

Using Interface Configuration Mode 10-4

 

 

 

 

 

 

 

 

 

 

Procedures for Configuring Interfaces

10-5

 

 

 

 

 

 

 

 

Configuring a Range of Interfaces

10-6

 

 

 

 

 

 

 

 

 

Configuring and Using Interface Range Macros

10-7

 

 

 

 

 

 

 

Configuring Ethernet Interfaces

10-9

 

 

 

 

 

 

 

 

 

 

 

Default Ethernet Interface Configuration

10-9

 

 

 

 

 

 

 

 

Configuring Interface Speed and Duplex Mode

10-10

 

 

 

 

 

 

Speed and Duplex Configuration Guidelines

10-11

 

 

 

 

 

 

Setting the Type of a Dual-Purpose Uplink Port

10-11

 

 

 

 

 

 

Setting the Interface Speed and Duplex Parameters 10-13

 

 

 

 

 

 

 

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Configuring IEEE 802.3x Flow Control

 

10-14

 

 

 

 

 

 

 

Configuring Auto-MDIX on an Interface

10-15

 

 

 

 

 

 

Adding a Description for an Interface

 

10-16

 

 

 

 

 

 

 

Configuring the System MTU 10-16

 

 

 

 

 

 

 

 

 

 

Monitoring and Maintaining the Interfaces

10-18

 

 

 

 

 

 

 

Monitoring Interface Status

10-18

 

 

 

 

 

 

 

 

 

 

Clearing and Resetting Interfaces and Counters

10-19

 

 

 

 

 

Shutting Down and Restarting the Interface

10-19

 

 

Configuring Smartports Macros

 

 

 

 

 

 

 

C H A P T E R 11

11-1

 

 

 

 

 

 

 

 

 

 

Understanding Smartports Macros

11-1

 

 

 

 

 

 

 

 

 

 

Configuring Smartports Macros

11-2

 

 

 

 

 

 

 

 

 

 

Default Smartports Macro Configuration

11-2

 

 

 

 

 

 

Smartports Macro Configuration Guidelines

11-3

 

 

 

 

 

Creating Smartports Macros

 

11-4

 

 

 

 

 

 

 

 

 

 

Applying Smartports Macros

 

11-5

 

 

 

 

 

 

 

 

 

 

Applying Cisco-Default Smartports Macros

11-6

 

 

 

 

 

Displaying Smartports Macros

11-8

 

 

 

 

 

 

 

Configuring VLANs 12-1

 

 

 

 

 

 

 

 

 

C H A P T E R 12

 

 

 

 

 

 

 

 

 

 

 

 

 

Understanding VLANs

12-1

 

 

 

 

 

 

 

 

 

 

 

 

Supported VLANs

12-2

 

 

 

 

 

 

 

 

 

 

 

 

VLAN Port Membership Modes

12-3

 

 

 

 

 

 

 

 

 

Configuring Normal-Range VLANs

12-4

 

 

 

 

 

 

 

 

 

 

Token Ring VLANs

12-5

 

 

 

 

 

 

 

 

 

 

 

 

Normal-Range VLAN Configuration Guidelines

 

12-5

 

 

 

 

 

VLAN Configuration Mode Options

12-6

 

 

 

 

 

 

 

 

VLAN Configuration in config-vlan Mode

 

12-6

 

 

 

 

 

VLAN Configuration in VLAN Database Configuration Mode 12-6

 

 

 

 

Saving VLAN Configuration

12-6

 

 

 

 

 

 

 

 

 

 

Default Ethernet VLAN Configuration

 

12-7

 

 

 

 

 

 

 

Creating or Modifying an Ethernet VLAN

12-8

 

 

 

 

 

 

Deleting a VLAN

12-9

 

 

 

 

 

 

 

 

 

 

 

 

Assigning Static-Access Ports to a VLAN

12-10

 

 

 

 

 

Configuring Extended-Range VLANs

12-11

 

 

 

 

 

 

 

 

 

Default VLAN Configuration

12-11

 

 

 

 

 

 

 

 

 

 

Extended-Range VLAN Configuration Guidelines

12-12

 

 

 

 

 

Creating an Extended-Range VLAN

12-12

 

 

 

 

 

 

 

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Displaying VLANs

12-13

 

 

 

 

 

 

Configuring VLAN Trunks

12-14

 

 

 

 

 

Trunking Overview

12-14

 

 

 

 

 

IEEE 802.1Q Configuration Considerations

12-15

 

Default Layer 2 Ethernet Interface VLAN Configuration

12-16

Configuring an Ethernet Interface as a Trunk Port 12-16

 

Interaction with Other Features

12-16

 

 

Configuring a Trunk Port

12-17

 

 

 

 

Defining the Allowed VLANs on a Trunk

12-18

 

Changing the Pruning-Eligible List

12-19

 

 

Configuring the Native VLAN for Untagged Traffic

12-19

Configuring Trunk Ports for Load Sharing

12-20

 

Load Sharing Using STP Port Priorities 12-20

 

Load Sharing Using STP Path Cost

12-22

 

 

Configuring VMPS

12-23

 

 

 

 

 

 

Understanding VMPS

12-24

 

 

 

 

 

Dynamic-Access Port VLAN Membership

12-24

 

Default VMPS Client Configuration

12-25

 

 

VMPS Configuration Guidelines

12-25

 

 

 

Configuring the VMPS Client

12-26

 

 

 

 

Entering the IP Address of the VMPS

12-26

Configuring Dynamic-Access Ports on VMPS Clients 12-26

Reconfirming VLAN Memberships 12-27

Changing the Reconfirmation Interval

12-27

Changing the Retry Count 12-28

 

 

 

Monitoring the VMPS

12-28

 

 

 

 

 

Troubleshooting Dynamic-Access Port VLAN Membership 12-29

 

 

VMPS Configuration Example 12-29

 

Configuring VTP

 

 

 

 

 

 

 

C H A P T E R 13

13-1

 

 

 

 

 

 

 

 

Understanding VTP

13-1

 

 

 

 

 

 

 

The VTP Domain

13-2

 

 

 

 

 

 

VTP Modes

13-3

 

 

 

 

 

 

 

VTP Advertisements

13-3

 

 

 

 

 

 

VTP Version 2

13-4

 

 

 

 

 

 

 

VTP Pruning

13-4

 

 

 

 

 

 

 

Configuring VTP

13-6

 

 

 

 

 

 

 

Default VTP Configuration

13-6

 

 

 

 

 

VTP Configuration Options

13-7

 

 

 

 

 

 

 

 

 

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Contents

 

 

 

 

VTP Configuration in Global Configuration Mode

13-7

 

 

 

 

 

VTP Configuration in VLAN Database Configuration Mode 13-7

 

 

 

 

VTP Configuration Guidelines

13-8

 

 

 

 

 

 

 

Domain Names

13-8

 

 

 

 

 

 

 

 

 

Passwords

13-8

 

 

 

 

 

 

 

 

 

 

VTP Version

13-8

 

 

 

 

 

 

 

 

 

 

Configuration Requirements

13-9

 

 

 

 

 

 

Configuring a VTP Server 13-9

 

 

 

 

 

 

 

 

Configuring a VTP Client

13-11

 

 

 

 

 

 

 

 

Disabling VTP (VTP Transparent Mode)

13-12

 

 

 

 

 

 

Enabling VTP Version 2

13-13

 

 

 

 

 

 

 

 

Enabling VTP Pruning

13-14

 

 

 

 

 

 

 

 

 

Adding a VTP Client Switch to a VTP Domain 13-14

 

 

 

 

 

 

Monitoring VTP

13-16

 

 

 

 

 

 

 

 

Configuring Voice VLAN

 

 

 

 

 

 

C H A P T E R 14

14-1

 

 

 

 

 

 

 

 

 

Understanding Voice VLAN

14-1

 

 

 

 

 

 

 

 

 

Cisco IP Phone Voice Traffic

14-2

 

 

 

 

 

 

 

 

Cisco IP Phone Data Traffic

14-2

 

 

 

 

 

 

 

 

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

14-4

 

 

 

 

 

Configuring IP Phone Voice Traffic

14-5

 

 

 

 

 

 

Configuring the Priority of Incoming Data Frames

14-6

 

 

 

 

 

Displaying Voice VLAN

14-6

 

 

 

 

 

 

Configuring STP

 

 

 

 

 

 

 

 

 

C H A P T E R 15

15-1

 

 

 

 

 

 

 

 

 

 

 

 

Understanding Spanning-Tree Features

15-1

 

 

 

 

 

 

STP Overview

15-2

 

 

 

 

 

 

 

 

 

 

 

Spanning-Tree Topology and BPDUs

15-3

 

 

 

 

 

 

Bridge ID, Switch Priority, and Extended System ID 15-4

 

 

 

 

Spanning-Tree Interface States 15-4

 

 

 

 

 

 

 

Blocking State

15-6

 

 

 

 

 

 

 

 

 

Listening State

15-6

 

 

 

 

 

 

 

 

 

Learning State

15-6

 

 

 

 

 

 

 

 

 

Forwarding State

15-6

 

 

 

 

 

 

 

 

 

Disabled State

15-7

 

 

 

 

 

 

 

 

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How a Switch or Port Becomes the Root Switch or Root Port

15-7

 

Spanning Tree and Redundant Connectivity 15-8

 

 

 

Spanning-Tree Address Management

15-8

 

 

 

Accelerated Aging to Retain Connectivity

15-8

 

 

 

Spanning-Tree Modes and Protocols

15-9

 

 

 

Supported Spanning-Tree Instances

15-9

 

 

 

Spanning-Tree Interoperability and Backward Compatibility

15-10

 

STP and IEEE 802.1Q Trunks

15-10

 

 

 

 

 

Configuring Spanning-Tree Features

15-10

 

 

 

 

Default Spanning-Tree Configuration

15-11

 

 

 

Spanning-Tree Configuration Guidelines

15-11

 

 

 

Changing the Spanning-Tree Mode.

15-12

 

 

 

Disabling Spanning Tree

15-13

 

 

 

 

 

 

Configuring the Root Switch

15-14

 

 

 

 

 

Configuring a Secondary Root Switch

15-15

 

 

 

Configuring Port Priority

15-16

 

 

 

 

 

 

Configuring Path Cost

15-17

 

 

 

 

 

 

 

Configuring the Switch Priority of a VLAN

15-19

 

 

 

Configuring Spanning-Tree Timers

15-19

 

 

 

Configuring the Hello Time

15-20

 

 

 

 

Configuring the Forwarding-Delay Time for a VLAN

15-21

 

Configuring the Maximum-Aging Time for a VLAN

15-21

 

 

Displaying the Spanning-Tree Status

15-22

 

 

 

 

Configuring MSTP

 

 

 

 

 

 

 

 

 

C H A P T E R 16

16-1

 

 

 

 

 

 

 

 

 

Understanding MSTP

16-2

 

 

 

 

 

 

 

 

Multiple Spanning-Tree Regions

16-2

 

 

 

 

IST, CIST, and CST

16-3

 

 

 

 

 

 

 

Operations Within an MST Region

16-3

 

 

 

Operations Between MST Regions

16-4

 

 

 

Hop Count

16-5

 

 

 

 

 

 

 

 

 

Boundary Ports 16-5

 

 

 

 

 

 

 

 

Interoperability with IEEE 802.1D STP

16-5

 

 

 

Understanding RSTP

16-6

 

 

 

 

 

 

 

 

Port Roles and the Active Topology

16-6

 

 

 

 

Rapid Convergence 16-7

 

 

 

 

 

 

 

Synchronization of Port Roles

16-8

 

 

 

 

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Bridge Protocol Data Unit Format and Processing

16-9

 

 

 

 

 

Processing Superior BPDU Information

16-10

 

 

 

 

 

 

Processing Inferior BPDU Information

16-10

 

 

 

 

 

 

Topology Changes

16-10

 

 

 

 

 

 

 

 

 

 

 

Configuring MSTP Features

16-11

 

 

 

 

 

 

 

 

 

Default MSTP Configuration

16-11

 

 

 

 

 

 

 

 

MSTP Configuration Guidelines

16-12

 

 

 

 

 

 

 

 

Specifying the MST Region Configuration and Enabling MSTP 16-13

 

 

 

 

Configuring the Root Switch

16-14

 

 

 

 

 

 

 

 

Configuring a Secondary Root Switch

16-15

 

 

 

 

 

 

Configuring Port Priority

 

16-16

 

 

 

 

 

 

 

 

 

Configuring Path Cost

16-17

 

 

 

 

 

 

 

 

 

 

Configuring the Switch Priority

16-18

 

 

 

 

 

 

 

 

Configuring the Hello Time

 

16-19

 

 

 

 

 

 

 

 

Configuring the Forwarding-Delay Time

16-20

 

 

 

 

 

 

Configuring the Maximum-Aging Time

16-20

 

 

 

 

 

 

Configuring the Maximum-Hop Count

16-21

 

 

 

 

 

 

Specifying the Link Type to Ensure Rapid Transitions 16-21

 

 

 

 

Restarting the Protocol Migration Process

16-22

 

 

 

 

 

 

Displaying the MST Configuration and Status

16-22

 

 

 

Configuring Optional Spanning-Tree Features

 

 

 

C H A P T E R 17

17-1

 

 

 

 

 

 

Understanding Optional Spanning-Tree Features

17-1

 

 

 

 

 

 

Understanding Port Fast

 

17-2

 

 

 

 

 

 

 

 

 

Understanding BPDU Guard

17-3

 

 

 

 

 

 

 

 

Understanding BPDU Filtering

17-3

 

 

 

 

 

 

 

 

Understanding UplinkFast

17-4

 

 

 

 

 

 

 

 

 

Understanding BackboneFast

17-5

 

 

 

 

 

 

 

 

Understanding EtherChannel Guard 17-7

 

 

 

 

 

 

 

Understanding Root Guard

17-8

 

 

 

 

 

 

 

 

 

Understanding Loop Guard

 

17-9

 

 

 

 

 

 

 

 

 

Configuring Optional Spanning-Tree Features

17-9

 

 

 

 

 

 

Default Optional Spanning-Tree Configuration 17-9

 

 

 

 

Optional Spanning-Tree Configuration Guidelines

17-10

 

 

 

 

 

Enabling Port Fast

17-10

 

 

 

 

 

 

 

 

 

 

 

Enabling BPDU Guard

17-11

 

 

 

 

 

 

 

 

 

 

Enabling BPDU Filtering

 

17-12

 

 

 

 

 

 

 

 

 

Enabling UplinkFast for Use with Redundant Links

17-13

 

 

 

 

 

Enabling BackboneFast

17-14

 

 

 

 

 

 

 

 

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Enabling EtherChannel Guard

17-14

 

 

Enabling Root Guard

17-15

 

 

 

 

 

Enabling Loop Guard

17-15

 

 

 

 

 

Displaying the Spanning-Tree Status

 

17-16

 

 

Configuring Flex Links

 

 

 

 

 

 

C H A P T E R 18

18-1

 

 

 

 

 

 

Understanding Flex Links

18-1

 

 

 

 

 

Configuring Flex Links

18-2

 

 

 

 

 

Default Flex Link Configuration

18-2

 

 

Flex Link Configuration Guidelines

18-2

 

 

Configuring Flex Links

18-3

 

 

 

 

Monitoring Flex Links

18-3

 

 

 

 

 

Configuring DHCP Features

 

 

 

 

 

C H A P T E R 19

19-1

 

 

 

 

 

Understanding DHCP Features

19-1

 

 

 

DHCP Server 19-2

 

 

 

 

 

 

DHCP Relay Agent 19-2

 

 

 

 

 

DHCP Snooping

19-2

 

 

 

 

 

 

Option-82 Data Insertion 19-3

 

 

 

 

DHCP Snooping Binding Database

19-5

 

 

Configuring DHCP Features

19-6

 

 

 

 

Default DHCP Configuration

19-7

 

 

 

DHCP Snooping Configuration Guidelines

19-7

 

Configuring the DHCP Relay Agent

19-8

 

 

Enabling DHCP Snooping and Option 82

19-9

 

Enabling the DHCP Snooping Binding Database Agent 19-10

 

Displaying DHCP Snooping Information

19-11

 

 

Configuring IGMP Snooping and MVR

 

 

C H A P T E R 20

20-1

 

 

Understanding IGMP Snooping

20-1

 

 

 

IGMP Versions

20-2

 

 

 

 

 

 

Joining a Multicast Group

20-3

 

 

 

Leaving a Multicast Group

20-4

 

 

 

Immediate Leave

20-5

 

 

 

 

 

IGMP Configurable-Leave Timer

 

20-5

 

 

IGMP Report Suppression

20-5

 

 

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Configuring IGMP Snooping 20-6

 

 

Default IGMP Snooping Configuration

20-6

Enabling or Disabling IGMP Snooping

20-6

Setting the Snooping Method 20-7

 

Configuring a Multicast Router Port

 

20-8

Configuring a Host Statically to Join a Group 20-9

Enabling IGMP Immediate Leave

20-9

Configuring the IGMP Leave Timer

20-10

Configuring TCN-Related Commands

 

20-11

 

 

Controlling the Multicast Flooding Time After a TCN Event 20-11

Recovering from Flood Mode 20-12

 

 

Disabling Multicast Flooding During a TCN Event

20-12

Configuring the IGMP Snooping Querier

20-13

 

 

Disabling IGMP Report Suppression

20-14

 

 

Displaying IGMP Snooping Information

20-14

 

 

Understanding Multicast VLAN Registration

20-16

 

 

Using MVR in a Multicast Television Application

20-16

Configuring MVR 20-18

 

 

 

 

 

 

Default MVR Configuration

20-18

 

 

 

 

MVR Configuration Guidelines and Limitations

20-18

 

Configuring MVR Global Parameters

20-19

 

 

Configuring MVR Interfaces

20-20

 

 

 

 

Displaying MVR Information

20-21

 

 

 

 

Configuring IGMP Filtering and Throttling

 

20-22

 

 

Default IGMP Filtering and Throttling Configuration

20-23

Configuring IGMP Profiles

 

20-23

 

 

 

 

Applying IGMP Profiles

20-24

 

 

 

 

 

 

 

 

Setting the Maximum Number of IGMP Groups

20-25

 

 

 

 

 

Configuring the IGMP Throttling Action

20-25

 

 

 

 

 

 

Displaying IGMP Filtering and Throttling Configuration

20-27

 

 

Configuring Port-Based Traffic Control

 

 

 

 

C H A P T E R 21

21-1

 

 

 

 

 

 

 

Configuring Storm Control

21-1

 

 

 

 

 

 

 

 

Understanding Storm Control 21-1

 

 

 

 

 

 

 

 

Default Storm Control Configuration

21-3

 

 

 

 

 

 

Configuring Storm Control and Threshold Levels

21-3

 

 

 

 

 

Configuring Protected Ports

21-5

 

 

 

 

 

 

 

 

Default Protected Port Configuration

21-5

 

 

 

 

 

 

Protected Port Configuration Guidelines

21-6

 

 

 

 

 

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Contents

 

 

Configuring a Protected Port

21-6

 

 

 

 

 

 

 

 

Configuring Port Blocking

21-6

 

 

 

 

 

 

 

 

 

Default Port Blocking Configuration

21-6

 

 

 

 

 

 

Blocking Flooded Traffic on an Interface

21-7

 

 

 

 

 

Configuring Port Security

21-7

 

 

 

 

 

 

 

 

 

Understanding Port Security

21-8

 

 

 

 

 

 

 

 

Secure MAC Addresses

21-8

 

 

 

 

 

 

 

 

Security Violations

21-9

 

 

 

 

 

 

 

 

Default Port Security Configuration

21-10

 

 

 

 

 

 

Port Security Configuration Guidelines

21-10

 

 

 

 

 

 

Enabling and Configuring Port Security

21-11

 

 

 

 

 

 

Enabling and Configuring Port Security Aging

21-15

 

 

 

 

 

Displaying Port-Based Traffic Control Settings 21-16

 

Configuring CDP

 

 

 

 

 

 

 

 

 

 

 

C H A P T E R 22

22-1

 

 

 

 

 

 

 

 

 

 

 

 

Understanding CDP

22-1

 

 

 

 

 

 

 

 

 

 

Configuring CDP

22-2

 

 

 

 

 

 

 

 

 

 

 

Default CDP Configuration

22-2

 

 

 

 

 

 

 

 

Configuring the CDP Characteristics

22-2

 

 

 

 

 

 

Disabling and Enabling CDP

22-3

 

 

 

 

 

 

 

 

Disabling and Enabling CDP on an Interface

22-4

 

 

 

 

 

Monitoring and Maintaining CDP

22-5

 

 

 

 

 

 

 

Configuring SPAN and RSPAN

 

 

 

 

 

 

 

C H A P T E R 23

23-1

 

 

 

 

 

 

 

 

Understanding SPAN and RSPAN

23-1

 

 

 

 

 

 

 

 

Local SPAN

23-2

 

 

 

 

 

 

 

 

 

 

 

Remote SPAN

23-2

 

 

 

 

 

 

 

 

 

 

 

SPAN and RSPAN Concepts and Terminology

23-3

 

 

 

 

 

SPAN Sessions

23-3

 

 

 

 

 

 

 

 

 

Monitored Traffic

23-4

 

 

 

 

 

 

 

 

Source Ports

23-5

 

 

 

 

 

 

 

 

 

 

Source VLANs

23-6

 

 

 

 

 

 

 

 

 

VLAN Filtering

23-6

 

 

 

 

 

 

 

 

 

Destination Port

23-6

 

 

 

 

 

 

 

 

 

RSPAN VLAN

23-8

 

 

 

 

 

 

 

 

 

 

SPAN and RSPAN Interaction with Other Features 23-8

 

 

Configuring SPAN and RSPAN

23-9

 

 

 

 

 

 

 

 

Default SPAN and RSPAN Configuration

23-9

 

 

 

 

 

Configuring Local SPAN

23-10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Contents

 

 

 

 

SPAN Configuration Guidelines

23-10

 

 

 

 

 

 

 

Creating a Local SPAN Session

23-10

 

 

 

 

 

 

 

Creating a Local SPAN Session and Configuring Incoming Traffic 23-13

 

 

 

 

Specifying VLANs to Filter

 

23-15

 

 

 

 

 

 

 

 

 

Configuring RSPAN

23-16

 

 

 

 

 

 

 

 

 

 

 

RSPAN Configuration Guidelines

23-16

 

 

 

 

 

 

 

Configuring a VLAN as an RSPAN VLAN

23-17

 

 

 

 

 

 

Creating an RSPAN Source Session

23-18

 

 

 

 

 

 

Creating an RSPAN Destination Session

23-19

 

 

 

 

 

 

Creating an RSPAN Destination Session and Configuring Incoming Traffic 23-20

 

 

 

 

Specifying VLANs to Filter

 

23-22

 

 

 

 

 

 

 

 

 

Displaying SPAN and RSPAN Status

23-23

 

 

 

 

 

Configuring UDLD

 

 

 

 

 

 

 

 

 

 

C H A P T E R 24

24-1

 

 

 

 

 

 

 

 

 

 

 

 

 

Understanding UDLD

24-1

 

 

 

 

 

 

 

 

 

 

 

 

Modes of Operation

24-1

 

 

 

 

 

 

 

 

 

 

 

Methods to Detect Unidirectional Links

24-2

 

 

 

 

 

 

 

Configuring UDLD

 

24-4

 

 

 

 

 

 

 

 

 

 

 

 

 

Default UDLD Configuration

24-4

 

 

 

 

 

 

 

 

 

Configuration Guidelines

24-4

 

 

 

 

 

 

 

 

 

 

Enabling UDLD Globally

24-5

 

 

 

 

 

 

 

 

 

 

 

Enabling UDLD on an Interface

 

24-5

 

 

 

 

 

 

 

 

 

Resetting an Interface Disabled by UDLD

24-6

 

 

 

 

 

 

Displaying UDLD Status

24-6

 

 

 

 

 

 

 

 

 

Configuring RMON

 

 

 

 

 

 

 

 

 

 

C H A P T E R 25

25-1

 

 

 

 

 

 

 

 

 

 

 

 

 

Understanding RMON

25-1

 

 

 

 

 

 

 

 

 

 

 

 

Configuring RMON

25-2

 

 

 

 

 

 

 

 

 

 

 

 

Default RMON Configuration

25-3

 

 

 

 

 

 

 

 

 

Configuring RMON Alarms and Events

 

25-3

 

 

 

 

 

 

 

Collecting Group History Statistics on an Interface

25-5

 

 

 

 

 

Collecting Group Ethernet Statistics on an Interface

25-6

 

 

 

 

 

Displaying RMON Status

25-6

 

 

 

 

 

 

 

 

Configuring System Message Logging

 

 

 

 

 

C H A P T E R 26

26-1

 

 

 

 

 

 

 

 

Understanding System Message Logging

26-1

 

 

 

 

 

 

 

Configuring System Message Logging

26-2

 

 

 

 

 

 

 

 

System Log Message Format

26-2

 

 

 

 

 

 

 

 

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Default System Message Logging Configuration

26-3

Disabling Message Logging

26-3

 

Setting the Message Display Destination Device

26-4

Synchronizing Log Messages

26-5

 

Enabling and Disabling Time Stamps on Log Messages 26-7

Enabling and Disabling Sequence Numbers in Log Messages 26-7

Defining the Message Severity Level 26-8

 

 

 

Limiting Syslog Messages Sent to the History Table and to SNMP 26-9

 

 

Configuring UNIX Syslog Servers

26-10

 

 

 

 

 

 

Logging Messages to a UNIX Syslog Daemon

26-11

 

 

 

 

 

Configuring the UNIX System Logging Facility

26-11

 

 

 

 

 

Displaying the Logging Configuration

26-12

 

 

 

 

 

Configuring SNMP

 

 

 

 

 

 

 

 

 

C H A P T E R 27

27-1

 

 

 

 

 

 

 

 

 

 

Understanding SNMP

27-1

 

 

 

 

 

 

 

 

 

SNMP Versions

27-2

 

 

 

 

 

 

 

 

 

 

SNMP Manager Functions

27-3

 

 

 

 

 

 

 

 

SNMP Agent Functions 27-4

 

 

 

 

 

 

 

 

SNMP Community Strings

27-4

 

 

 

 

 

 

 

 

Using SNMP to Access MIB Variables

27-4

 

 

 

 

 

 

SNMP Notifications

27-5

 

 

 

 

 

 

 

 

 

SNMP ifIndex MIB Object Values

27-5

 

 

 

 

 

 

Configuring SNMP

27-6

 

 

 

 

 

 

 

 

 

 

Default SNMP Configuration

27-6

 

 

 

 

 

 

 

SNMP Configuration Guidelines

27-7

 

 

 

 

 

 

 

Disabling the SNMP Agent

27-8

 

 

 

 

 

 

 

 

Configuring Community Strings

27-8

 

 

 

 

 

 

 

Configuring SNMP Groups and Users

27-9

 

 

 

 

 

 

Configuring SNMP Notifications

27-11

 

 

 

 

 

 

Setting the Agent Contact and Location Information

27-14

 

 

 

 

 

Limiting TFTP Servers Used Through SNMP 27-15

 

 

 

 

 

 

SNMP Examples

27-15

 

 

 

 

 

 

 

 

 

Displaying SNMP Status

27-16

 

 

 

 

 

 

 

 

Configuring Network Security with ACLs

 

 

 

 

 

C H A P T E R 28

28-1

 

 

 

 

 

 

Understanding ACLs

28-1

 

 

 

 

 

 

 

 

 

 

Port ACLs

28-2

 

 

 

 

 

 

 

 

 

 

 

Handling Fragmented and Unfragmented Traffic 28-3

 

 

 

 

 

 

 

 

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Configuring IPv4 ACLs 28-4

 

 

Creating Standard and Extended IPv4 ACLs

28-5

Access List Numbers 28-6

 

 

Creating a Numbered Standard ACL

28-7

Creating a Numbered Extended ACL

28-8

Resequencing ACEs in an ACL

28-12

 

Creating Named Standard and Extended ACLs 28-12

Using Time Ranges with ACLs

28-14

 

Including Comments in ACLs

28-15

 

 

Applying an IPv4 ACL to a Terminal Line 28-16

 

 

Applying an IPv4 ACL to an Interface

28-17

 

 

 

Hardware and Software Treatment of IP ACLs

28-17

 

IPv4 ACL Configuration Examples

28-18

 

 

 

Numbered ACLs

28-18

 

 

 

 

 

 

Extended ACLs

28-18

 

 

 

 

 

 

Named ACLs

28-19

 

 

 

 

 

 

Time Range Applied to an IP ACL

28-19

 

 

 

Commented IP ACL Entries

 

28-19

 

 

 

Creating Named MAC Extended ACLs

28-20

 

 

 

Applying a MAC ACL to a Layer 2 Interface

28-21

 

 

Displaying IPv4 ACL Configuration

28-22

 

 

 

 

Configuring QoS 29-1

 

 

 

 

 

 

 

C H A P T E R 29

 

 

 

 

 

 

 

 

Understanding QoS

29-1

 

 

 

 

 

 

 

Basic QoS Model

29-3

 

 

 

 

 

 

Classification 29-5

 

 

 

 

 

 

 

Classification Based on QoS ACLs

29-7

 

 

 

Classification Based on Class Maps and Policy Maps 29-7

 

Policing and Marking

29-8

 

 

 

 

 

 

Policing on Physical Ports

29-9

 

 

 

 

Mapping Tables

29-10

 

 

 

 

 

 

Queueing and Scheduling Overview

29-11

 

 

 

Weighted Tail Drop 29-12

 

 

 

 

 

 

SRR Shaping and Sharing

 

29-12

 

 

 

 

Queueing and Scheduling on Ingress Queues

29-13

 

Queueing and Scheduling on Egress Queues

29-15

 

Packet Modification

29-18

 

 

 

 

 

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Configuring Auto-QoS 29-19

 

 

 

 

 

 

 

 

 

 

 

 

Generated Auto-QoS Configuration

29-19

 

 

 

 

 

 

 

 

Effects of Auto-QoS on the Configuration

29-24

 

 

 

 

 

 

 

Auto-QoS Configuration Guidelines

29-24

 

 

 

 

 

 

 

 

Enabling Auto-QoS for VoIP

29-25

 

 

 

 

 

 

 

 

 

 

Auto-QoS Configuration Example 29-26

 

 

 

 

 

 

 

 

 

Displaying Auto-QoS Information

29-28

 

 

 

 

 

 

 

 

 

 

Configuring Standard QoS 29-28

 

 

 

 

 

 

 

 

 

 

 

Default Standard QoS Configuration

29-29

 

 

 

 

 

 

 

 

Default Ingress Queue Configuration

 

29-29

 

 

 

 

 

 

 

Default Egress Queue Configuration

29-30

 

 

 

 

 

 

 

Default Mapping Table Configuration

 

29-31

 

 

 

 

 

 

 

Standard QoS Configuration Guidelines

29-31

 

 

 

 

 

 

 

QoS ACL Guidelines

29-31

 

 

 

 

 

 

 

 

 

 

Policing Guidelines

29-31

 

 

 

 

 

 

 

 

 

 

General QoS Guidelines

29-32

 

 

 

 

 

 

 

 

 

 

Enabling QoS Globally

29-32

 

 

 

 

 

 

 

 

 

 

 

Configuring Classification Using Port Trust States

29-32

 

 

 

 

 

 

Configuring the Trust State on Ports within the QoS Domain 29-33

 

 

 

 

 

Configuring the CoS Value for an Interface 29-34

 

 

 

 

 

 

Configuring a Trusted Boundary to Ensure Port Security

29-35

 

 

 

 

 

Enabling DSCP Transparency Mode

29-36

 

 

 

 

 

 

 

Configuring the DSCP Trust State on a Port Bordering Another QoS Domain 29-37

 

 

 

 

 

Configuring a QoS Policy

29-39

 

 

 

 

 

 

 

 

 

 

Classifying Traffic by Using ACLs

29-40

 

 

 

 

 

 

 

Classifying Traffic by Using Class Maps

29-43

 

 

 

 

 

 

 

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

29-45

 

 

Classifying, Policing, and Marking Traffic by Using Aggregate Policers 29-48

 

 

 

 

 

Configuring DSCP Maps

29-51

 

 

 

 

 

 

 

 

 

 

Configuring the CoS-to-DSCP Map

29-51

 

 

 

 

 

 

 

Configuring the IP-Precedence-to-DSCP Map

29-52

 

 

 

 

 

 

Configuring the Policed-DSCP Map

29-53

 

 

 

 

 

 

 

Configuring the DSCP-to-CoS Map

29-54

 

 

 

 

 

 

 

Configuring the DSCP-to-DSCP-Mutation Map

29-55

 

 

 

 

 

 

Configuring Ingress Queue Characteristics

29-57

 

 

 

 

 

 

 

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

29-57

 

 

Allocating Buffer Space Between the Ingress Queues

29-59

 

 

 

 

 

Allocating Bandwidth Between the Ingress Queues 29-60

 

 

 

 

 

Configuring the Ingress Priority Queue

29-61

 

 

 

 

 

 

 

 

 

 

 

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Configuring Egress Queue Characteristics

 

29-62

 

 

 

 

 

 

 

Configuration Guidelines 29-62

 

 

 

 

 

 

 

 

 

 

Allocating Buffer Space to and Setting WTD Thresholds for an Egress Queue-Set 29-62

 

 

 

 

Mapping DSCP or CoS Values to an Egress Queue and to a Threshold ID 29-64

 

 

 

 

Configuring SRR Shaped Weights on Egress Queues

29-66

 

 

 

 

 

Configuring SRR Shared Weights on Egress Queues

29-67

 

 

 

 

 

Configuring the Egress Expedite Queue

29-68

 

 

 

 

 

 

Limiting the Bandwidth on an Egress Interface

29-68

 

 

 

 

 

 

Displaying Standard QoS Information

29-69

 

 

 

 

 

 

Configuring EtherChannels

 

 

 

 

 

 

 

 

C H A P T E R 30

30-1

 

 

 

 

 

 

 

 

 

 

 

Understanding EtherChannels

30-1

 

 

 

 

 

 

 

 

 

 

 

EtherChannel Overview

 

30-2

 

 

 

 

 

 

 

 

 

 

 

Port-Channel Interfaces

 

30-3

 

 

 

 

 

 

 

 

 

 

 

Port Aggregation Protocol

30-4

 

 

 

 

 

 

 

 

 

 

 

PAgP Modes

30-4

 

 

 

 

 

 

 

 

 

 

 

 

PAgP Interaction with Other Features

 

30-5

 

 

 

 

 

 

 

Link Aggregation Control Protocol

30-5

 

 

 

 

 

 

 

 

 

LACP Modes

30-5

 

 

 

 

 

 

 

 

 

 

 

 

LACP Interaction with Other Features

 

30-6

 

 

 

 

 

 

 

EtherChannel On Mode

 

30-6

 

 

 

 

 

 

 

 

 

 

 

Load Balancing and Forwarding Methods

30-6

 

 

 

 

 

 

 

Configuring EtherChannels

30-8

 

 

 

 

 

 

 

 

 

 

 

Default EtherChannel Configuration

30-9

 

 

 

 

 

 

 

 

EtherChannel Configuration Guidelines

30-9

 

 

 

 

 

 

 

Configuring Layer 2 EtherChannels

30-10

 

 

 

 

 

 

 

 

Configuring EtherChannel Load Balancing

 

30-12

 

 

 

 

 

 

 

Configuring the PAgP Learn Method and Priority

30-13

 

 

 

 

 

 

Configuring LACP Hot-Standby Ports

30-14

 

 

 

 

 

 

 

 

Configuring the LACP System Priority

 

30-15

 

 

 

 

 

 

 

Configuring the LACP Port Priority

30-15

 

 

 

 

 

 

 

Displaying EtherChannel, PAgP, and LACP Status

30-16

 

 

 

Troubleshooting 31-1

 

 

 

 

 

 

 

 

 

 

C H A P T E R 31

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Recovering from a Software Failure

31-2

 

 

 

 

 

 

 

 

 

 

Recovering from a Lost or Forgotten Password

 

31-3

 

 

 

 

 

 

 

Procedure with Password Recovery Enabled

31-4

 

 

 

 

 

 

 

Procedure with Password Recovery Disabled

31-6

 

 

 

 

 

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Recovering from a Command Switch Failure

31-7

 

 

 

 

 

 

 

 

Replacing a Failed Command Switch with a Cluster Member

31-8

 

 

 

 

 

 

Replacing a Failed Command Switch with Another Switch

31-9

 

 

 

 

 

 

Recovering from Lost Cluster Member Connectivity

31-11

 

 

 

 

 

 

 

Preventing Autonegotiation Mismatches

31-11

 

 

 

 

 

 

 

 

SFP Module Security and Identification

31-11

 

 

 

 

 

 

 

 

 

Monitoring SFP Module Status

31-12

 

 

 

 

 

 

 

 

 

 

Using Ping

31-12

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Understanding Ping

31-12

 

 

 

 

 

 

 

 

 

 

 

Executing Ping

31-13

 

 

 

 

 

 

 

 

 

 

 

 

Using Layer 2 Traceroute

31-13

 

 

 

 

 

 

 

 

 

 

 

Understanding Layer 2 Traceroute

31-14

 

 

 

 

 

 

 

 

 

Usage Guidelines

 

31-14

 

 

 

 

 

 

 

 

 

 

 

 

Displaying the Physical Path

31-15

 

 

 

 

 

 

 

 

 

 

Using IP Traceroute

31-15

 

 

 

 

 

 

 

 

 

 

 

 

Understanding IP Traceroute

31-15

 

 

 

 

 

 

 

 

 

Executing IP Traceroute

31-16

 

 

 

 

 

 

 

 

 

 

Using TDR

31-17

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Understanding TDR

31-17

 

 

 

 

 

 

 

 

 

 

 

Running TDR and Displaying the Results

31-17

 

 

 

 

 

 

 

 

Using Debug Commands

31-18

 

 

 

 

 

 

 

 

 

 

 

Enabling Debugging on a Specific Feature

31-18

 

 

 

 

 

 

 

Enabling All-System Diagnostics 31-19

 

 

 

 

 

 

 

 

 

Redirecting Debug and Error Message Output

31-19

 

 

 

 

 

 

 

Using the show platform forward Command

31-19

 

 

 

 

 

 

 

 

Using the crashinfo File

31-21

 

 

 

 

 

 

 

 

 

 

Supported MIBs A-1

 

 

 

 

 

 

 

 

 

 

 

A P P E N D I X

A

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MIB List

A-1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Using FTP to Access the MIB Files

A-3

 

 

 

 

 

 

 

 

 

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

A P P E N D I X

B

 

 

 

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-3

 

 

 

Creating and Removing Directories

B-4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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B-26
B-25

Contents

Copying Files

B-4

 

 

 

 

 

 

 

Deleting Files

B-5

 

 

 

 

 

 

 

Creating, Displaying, and Extracting tar Files B-5

 

 

Creating a tar File

B-6

 

 

 

 

 

 

Displaying the Contents of a tar File

B-6

 

 

 

Extracting a tar File

B-7

 

 

 

 

 

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 B-9

 

 

 

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 By Using TFTP

B-10

Downloading the Configuration File By Using TFTP B-11

 

Uploading the Configuration File By Using TFTP

B-11

 

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

 

 

 

Working with Software Images

B-19

 

 

 

 

 

Image Location on the Switch

B-20

 

 

 

 

tar File Format of Images on a Server or Cisco.com

B-20

 

Copying Image Files By Using TFTP

B-21

 

 

 

 

Preparing to Download or Upload an Image File By Using TFTP B-21

 

Downloading an Image File By Using TFTP

B-22

 

Uploading an Image File By Using TFTP

B-24

 

 

Copying Image Files By Using FTP

B-24

 

 

 

 

Preparing to Download or Upload an Image File By Using FTP

Downloading an Image File By Using FTP

Uploading an Image File By Using FTP

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B-32
B-31

Contents

Copying Image Files By Using RCP B-29

Preparing to Download or Upload an Image File By Using RCP B-29

Downloading an Image File By Using RCP

Uploading an Image File By Using RCP

A P P E N D I X

C

Recommendations for Upgrading a Catalyst 2950 Switch to a Catalyst 2960 Switch C-1

 

 

Configuration Compatibility Issues

C-1

 

 

 

 

Feature Behavior Incompatibilities

C-5

 

 

 

 

Unsupported Commands in Cisco IOS Release 12.2(25)FX D-1

A P P E N D I X

D

 

 

Access Control Lists

D-1

 

 

 

 

 

 

Unsupported Privileged EXEC Commands

D-1

 

 

 

Unsupported Global Configuration Commands

D-1

 

 

Debug Commands

D-1

 

 

 

 

 

 

Unsupported Privileged EXEC Commands

D-1

 

 

 

IGMP Snooping Commands

D-2

 

 

 

 

 

Unsupported Global Configuration Commands

D-2

 

 

Interface Commands

D-2

 

 

 

 

 

 

Unsupported Privileged EXEC Commands

D-2

 

 

 

Unsupported Global Configuration Commands

D-2

 

 

Unsupported Interface Configuration Commands

D-2

 

 

MAC Address Commands

D-2

 

 

 

 

 

Unsupported Privileged EXEC Commands

D-2

 

 

 

Unsupported Global Configuration Commands

D-3

 

 

Miscellaneous D-3

 

 

 

 

 

 

 

Unsupported Privileged EXEC Commands

D-3

 

 

 

Unsupported Global Configuration Commands

D-3

 

 

Network Address Translation (NAT) Commands

D-3

 

 

Unsupported Privileged EXEC Commands

D-3

 

 

 

QoS

D-3

 

 

 

 

 

 

 

Unsupported Global Configuration Commands

D-3

 

 

Unsupported Interface Configuration Commands

D-4

 

 

RADIUS D-4

 

 

 

 

 

 

 

Unsupported Global Configuration Commands

D-4

 

 

SNMP

D-4

 

 

 

 

 

 

 

Unsupported Global Configuration Commands

D-4

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Contents

Spanning Tree D-4

 

 

Unsupported Global Configuration Command

D-4

Unsupported Interface Configuration Command

D-4

VLAN

D-4

 

 

Unsupported Global Configuration Commands

D-4

Unsupported vlan-config Command

D-5

 

Unsupported User EXEC Commands

D-5

 

VTP

D-5

 

 

Unsupported Privileged EXEC Commands D-5

I N D E X

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Preface

Audience

This guide is for the networking professional managing the Catalyst 2960 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.

Purpose

This guide provides the information that you need to configure Cisco IOS software features on your switch. The Catalyst 2960 software provides enterprise-classintelligent 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 Catalyst 2960 switch. It does not provide detailed information about these commands. For detailed information about these commands, see the Catalyst 2960 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 atTechnical Support & 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, seeGetting 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 2960 Switch System Message Guide for this release and to the

Catalyst 2960 Switch Hardware Installation Guide.

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

 

 

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Conventions

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 element.

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:

Note Meansreader take note. Notes contain helpful suggestions or references to materials not contained in this manual.

Caution Meansreader 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/univercd/cc/td/doc/product/lan/cat2960/index.htm

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

For initial configuration information, see the “Using Express Setup” chapter in the getting started guide or the “Configuring the Switch with the CLI-BasedSetup 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).

 

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Obtaining Documentation

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.

You can order printed copies of documents with a DOC-xxxxxx=number from the Cisco.com sites and from the telephone numbers listed in the“Obtaining Documentation” section on page xxix.

Release Notes for the Catalyst 2960 Switches (not orderable but available on Cisco.com)

Catalyst 2960 Switch Software Configuration Guide (order number DOC-7816881=)

Catalyst 2960 Switch Command Reference (order number DOC-7816882=)

Catalyst 2960 Switch System Message Guide (order number DOC-7816883=)

Device manager online help (available on the switch)

Catalyst 2960 Switch Hardware Installation Guide (not orderable but available on Cisco.com)

Catalyst 2960 Switch Getting Started Guide (order number DOC-7816879=)

Regulatory Compliance and Safety Information for the Catalyst 2960 Switch (order number DOC-7816880=)

Getting Started with Cisco Network Assistant (not orderable but available on Cisco.com)

Release Notes for Cisco Network Assistant (not orderable but available on Cisco.com)

Cisco Small Form-FactorPluggable Modules Installation Notes(order number DOC-7815160=)

Cisco CWDM GBIC and CWDM SFP Installation Note (not orderable but available on Cisco.com)

Cisco RPS 300 Redundant Power System Hardware Installation Guide (order number DOC-7810372=)

Cisco RPS 675 Redundant Power System Hardware Installation Guide (order number DOC-7815201=)

Obtaining Documentation

Cisco documentation and additional literature are available on Cisco.com. Cisco also provides several ways to obtain technical assistance and other technical resources. These sections explain how to obtain technical information from Cisco Systems.

Cisco.com

You can access the most current Cisco documentation at this URL:

http://www.cisco.com/techsupport

You can access the Cisco website at this URL:

http://www.cisco.com

You can access international Cisco websites at this URL:

http://www.cisco.com/public/countries_languages.shtml

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Preface

Documentation Feedback

Product Documentation DVD

Cisco documentation and additional literature are available in the Product Documentation DVD package, which may have shipped with your product. The Product Documentation DVD is updated regularly and may be more current than printed documentation.

The Product Documentation DVD is a comprehensive library of technical product documentation on portable media. The DVD enables you to access multiple versions of hardware and software installation, configuration, and command guides for Cisco products and to view technical documentation in HTML. With the DVD, you have access to the same documentation that is found on the Cisco website without being connected to the Internet. Certain products also have .pdf versions of the documentation available.

The Product Documentation DVD is available as a single unit or as a subscription. Registered Cisco.com users (Cisco direct customers) can order a Product Documentation DVD (product number DOC-DOCDVD=)from Cisco Marketplace at this URL:

http://www.cisco.com/go/marketplace/

Ordering Documentation

Beginning June 30, 2005, registered Cisco.com users may order Cisco documentation at the Product Documentation Store in the Cisco Marketplace at this URL:

http://www.cisco.com/go/marketplace/

Nonregistered Cisco.com users can order technical documentation from 8:00 a.m. to 5:00 p.m. (0800 to 1700) PDT by calling 1 866 463-3487in the United States and Canada, or elsewhere by calling 011 408519-5055.You can also order documentation bye-mailat

tech-doc-store-mkpl@external.cisco.com or by fax at 1 408519-5001in the United States and Canada, or elsewhere at 011 408519-5001.

Documentation Feedback

You can rate and provide feedback about Cisco technical documents by completing the online feedback form that appears with the technical documents on Cisco.com.

You can send comments about Cisco documentation to bug-doc@cisco.com.

You can submit comments by using the response card (if present) behind the front cover of your document or by writing to the following address:

Cisco Systems

Attn: Customer Document Ordering

170 West Tasman Drive

San Jose, CA 95134-9883

We appreciate your comments.

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Preface

Cisco Product Security Overview

Cisco Product Security Overview

Cisco provides a free online Security Vulnerability Policy portal at this URL:

http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html

From this site, you can perform these tasks:

Report security vulnerabilities in Cisco products.

Obtain assistance with security incidents that involve Cisco products.

Register to receive security information from Cisco.

A current list of security advisories and notices for Cisco products is available at this URL:

http://www.cisco.com/go/psirt

If you prefer to see advisories and notices as they are updated in real time, you can access a Product Security Incident Response Team Really Simple Syndication (PSIRT RSS) feed from this URL:

http://www.cisco.com/en/US/products/products_psirt_rss_feed.html

Reporting Security Problems in Cisco Products

Cisco is committed to delivering secure products. We test our products internally before we release them, and we strive to correct all vulnerabilities quickly. If you think that you might have identified a vulnerability in a Cisco product, contact PSIRT:

Emergencies — security-alert@cisco.com

An emergency is either a condition in which a system is under active attack or a condition for which a severe and urgent security vulnerability should be reported. All other conditions are considered nonemergencies.

Nonemergencies — psirt@cisco.com

In an emergency, you can also reach PSIRT by telephone:

1 877 228-7302

1 408 525-6532

Tip We encourage you to use Pretty Good Privacy (PGP) or a compatible product to encrypt any sensitive information that you send to Cisco. PSIRT can work from encrypted information that is compatible with PGP versions 2.x through 8.x.

Never use a revoked or an expired encryption key. The correct public key to use in your correspondence with PSIRT is the one linked in the Contact Summary section of the Security Vulnerability Policy page at this URL:

http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html

The link on this page has the current PGP key ID in use.

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Obtaining Technical Assistance

Obtaining Technical Assistance

Cisco Technical Support provides 24-hour-a-dayaward-winningtechnical assistance. The Cisco Technical Support & Documentation website on Cisco.com features extensive online support resources. In addition, if you have a valid Cisco service contract, Cisco Technical Assistance Center (TAC) engineers provide telephone support. If you do not have a valid Cisco service contract, contact your reseller.

Cisco Technical Support & Documentation Website

The Cisco Technical Support & Documentation website provides online documents and tools for troubleshooting and resolving technical issues with Cisco products and technologies. The website is available 24 hours a day, at this URL:

http://www.cisco.com/techsupport

Access to all tools on the Cisco Technical Support & Documentation website requires a Cisco.com user ID and password. If you have a valid service contract but do not have a user ID or password, you can register at this URL:

http://tools.cisco.com/RPF/register/register.do

Note Use the Cisco Product Identification (CPI) tool to locate your product serial number before submitting a web or phone request for service. You can access the CPI tool from the Cisco Technical Support & Documentation website by clicking theTools & Resources link under Documentation & Tools. ChooseCisco Product Identification Tool from the Alphabetical Indexdrop-downlist, or click theCisco Product Identification Tool link under Alerts & RMAs. The CPI tool offers three search options: by product ID or model name; by tree view; or for certain products, by copying and pastingshow command output. Search results show an illustration of your product with the serial number label location highlighted. Locate the serial number label on your product and record the information before placing a service call.

Submitting a Service Request

Using the online TAC Service Request Tool is the fastest way to open S3 and S4 service requests. (S3 and S4 service requests are those in which your network is minimally impaired or for which you require product information.) After you describe your situation, the TAC Service Request Tool provides recommended solutions. If your issue is not resolved using the recommended resources, your service request is assigned to a Cisco engineer. The TAC Service Request Tool is located at this URL:

http://www.cisco.com/techsupport/servicerequest

For S1 or S2 service requests or if you do not have Internet access, contact the Cisco TAC by telephone. (S1 or S2 service requests are those in which your production network is down or severely degraded.) Cisco engineers are assigned immediately to S1 and S2 service requests to help keep your business operations running smoothly.

 

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Preface

Obtaining Additional Publications and Information

To open a service request by telephone, use one of the following numbers:

Asia-Pacific:+61 2 8446 7411 (Australia: 1 800 805 227)

EMEA: +32 2 704 55 55

USA: 1 800 553-2447

For a complete list of Cisco TAC contacts, go to this URL:

http://www.cisco.com/techsupport/contacts

Definitions of Service Request Severity

To ensure that all service requests are reported in a standard format, Cisco has established severity definitions.

Severity 1 (S1)—Yournetwork is “down,” or there is a critical impact to your business operations. You and Cisco will commit all necessary resources around the clock to resolve the situation.

Severity 2 (S2)—Operationof an existing network is severely degraded, or significant aspects of your business operation are negatively affected by inadequate performance of Cisco products. You and Cisco will commitfull-timeresources during normal business hours to resolve the situation.

Severity 3 (S3)—Operationalperformance of your network is impaired, but most business operations remain functional. You and Cisco will commit resources during normal business hours to restore service to satisfactory levels.

Severity 4 (S4)—Yourequire information or assistance with Cisco product capabilities, installation, or configuration. There is little or no effect on your business operations.

Obtaining Additional Publications and Information

Information about Cisco products, technologies, and network solutions is available from various online and printed sources.

Cisco Marketplace provides a variety of Cisco books, reference guides, documentation, and logo merchandise. Visit Cisco Marketplace, the company store, at this URL:

http://www.cisco.com/go/marketplace/

Cisco Press publishes a wide range of general networking, training and certification titles. Both new and experienced users will benefit from these publications. For current Cisco Press titles and other information, go to Cisco Press at this URL:

http://www.ciscopress.com

Packet magazine is the Cisco Systems technical user magazine for maximizing Internet and networking investments. Each quarter, Packet delivers coverage of the latest industry trends, technology breakthroughs, and Cisco products and solutions, as well as network deployment and troubleshooting tips, configuration examples, customer case studies, certification and training information, and links to scores ofin-depthonline resources. You can access Packet magazine at this URL:

http://www.cisco.com/packet

 

 

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Obtaining Additional Publications and Information

iQ Magazine is the quarterly publication from Cisco Systems designed to help growing companies learn how they can use technology to increase revenue, streamline their business, and expand services. The publication identifies the challenges facing these companies and the technologies to help solve them, usingreal-worldcase studies and business strategies to help readers make sound technology investment decisions. You can access iQ Magazine at this URL:

http://www.cisco.com/go/iqmagazine or view the digital edition at this URL:

http://ciscoiq.texterity.com/ciscoiq/sample/

Internet Protocol Journal is a quarterly journal published by Cisco Systems for engineering professionals involved in designing, developing, and operating public and private internets and intranets. You can access the Internet Protocol Journal at this URL:

http://www.cisco.com/ipj

Networking products offered by Cisco Systems, as well as customer support services, can be obtained at this URL:

http://www.cisco.com/en/US/products/index.html

Networking Professionals Connection is an interactive website for networking professionals to share questions, suggestions, and information about networking products and technologies with Cisco experts and other networking professionals. Join a discussion at this URL:

http://www.cisco.com/discuss/networking

World-classnetworking training is available from Cisco. You can view current offerings at this URL:

http://www.cisco.com/en/US/learning/index.html

 

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C H A P T E R 1

Overview

This chapter provides these topics about the Catalyst 2960 switch software:

Features, page 1-1

Default Settings After Initial Switch Configuration, page 1-8

Network Configuration Examples, page 1-11

Where to Go Next, page 1-16

In this document, IP refers to IP Version 4 (IPv4).

Features

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.

The switch has these features:

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

Performance Features, page 1-3

Management Options, page 1-3

Manageability Features, page 1-4 (includes a feature requiring the cryptographic version of the software)

Availability Features, page 1-5

VLAN Features, page 1-6

Security Features, page 1-6 (includes a feature requiring the cryptographic version of the software)

QoS and CoS Features, page 1-7

Monitoring Features, page 1-8

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Chapter 1 Overview

Features

Ease-of-UseandEase-of-DeploymentFeatures

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-basedprogram. For more information about Express Setup, see the getting started guide.

User-definedandCisco-defaultSmartports 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 and switch cluster management from anywhere in your intranet.

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

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 video 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, linkand switch-levelmonitoring 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-timestatus of a switch or multiple switches from the LEDs on thefront-panelimages. The system, redundant power system (RPS), and port LED colors on the images are similar to those used on the physical LEDs.

Switch clustering technology for

Unified configuration, monitoring, authentication, and software upgrade of multiple, cluster-capableswitches, regardless of their geographic proximity and interconnection media, including Ethernet, Fast Ethernet, Fast EtherChannel, smallform-factorpluggable (SFP) modules, Gigabit Ethernet, and Gigabit EtherChannel connections. For a list ofcluster-capableswitches, 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.

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Chapter 1 Overview

Features

Performance Features

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

Automatic-medium-dependentinterface crossover(auto-MDIX)capability on 10/100 and 10/100/1000 Mbps interfaces and on 10/100/1000BASE-TXSFP module interface that enables the interface to automatically detect the required cable connection type(straight-throughor crossover) and to configure the connection appropriately

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)

EtherChannel for enhanced fault tolerance and for providing up to 8 Gbps (Gigabit EtherChannel) or 800 Mbps (Fast EtherChannel) full-duplexbandwidth 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

Per-portstorm 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

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 configurable leave timer to configure the leave latency for the network.

Switch Database Management (SDM) templates for allocating system resources to maximize support for user-selectedfeatures

Management Options

An embedded device manager—Thedevice 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—NetworkAssistant 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, seeGetting Started with Cisco Network Assistant, available on Cisco.com.

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Chapter 1 Overview

Features

CLI—TheCisco IOS software supports desktopandmultilayer-switchingfeatures. You can access the CLI either by connecting your management station directly to the switch console port or by using Telnet from a remote management station. For more information about the CLI, seeChapter 2, “Using the Command-Line Interface.”

SNMP—SNMPmanagement applications such as CiscoWorks2000 LAN Management Suite (LMS) and HP OpenView. You can manage from anSNMP-compatiblemanagement 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, seeChapter 27, “Configuring SNMP.”

IE2100—CiscoIntelligence Engine 2100 Series Configuration Registrar is a network management device that works with embedded Cisco Networking Services (CNS) agents in the switch software. You can automate initial configurations and configuration updates by generatingswitch-specificconfiguration changes, sending them to the switch, executing the configuration change, and logging the results.

For more information about IE2100, see Chapter 4, “Understanding CNS Embedded Agents.”

Manageability Features

Cisco IE2100 Series 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

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

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

Cisco Discovery Protocol (CDP) Versions 1 and 2 for network topology discovery and mapping between the switch and other Cisco devices on the network

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

Unique device identifier to provide product identification information through a show inventory user EXEC command display

In-bandmanagement access through the device manager over a Netscape Navigator or Microsoft Internet Explorer browser session

In-bandmanagement access for up to 16 simultaneous Telnet connections for multipleCLI-basedsessions over the network

In-bandmanagement access for up to five simultaneous, encrypted Secure Shell (SSH) connections for multipleCLI-basedsessions over the network (requires the cryptographic version of the software)

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Chapter 1 Overview

Features

In-bandmanagement access through SNMP Versions 1, 2c, and 3 get and set requests

Out-of-bandmanagement access through the switch console port to a directly attached terminal or to a remote terminal through a serial connection or a modem

Note For additional descriptions of the management interfaces, see the“Network Configuration Examples” section on page 1-11.

Availability Features

UniDirectional Link Detection (UDLD) and aggressive UDLD for detecting and disabling unidirectional links on fiber-opticinterfaces caused by incorrectfiber-opticwiring or port faults

IEEE 802.1D Spanning Tree Protocol (STP) for redundant backbone connections and loop-freenetworks. STP has these features:

Up to 128 spanning-treeinstances supported

Per-VLANspanning-treeplus (PVST+) for balancing load across VLANs

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

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

IEEE 802.1s Multiple Spanning Tree Protocol (MSTP) for grouping VLANs into a spanning-treeinstance and for providing multiple forwarding paths for data traffic and load balancing and rapidper-VLANSpanning-Treeplus(rapid-PVST+)based on the IEEE 802.1w Rapid Spanning Tree Protocol (RSTP) for rapid convergence of the spanning tree by immediately transitioning root and designated ports to the forwarding state

Optional spanning-treefeatures available in PVST+,rapid-PVST+,and MSTP mode:

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

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

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

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

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

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

RPS support through the Cisco RPS 300 and Cisco RPS 675 for enhancing power reliability

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Features

VLAN Features

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-securityusers 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

VLAN1 minimization for reducing the risk of spanning-treeloops or storms by allowing VLAN 1 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.

Security Features

Password-protectedaccess(read-onlyandread-writeaccess) to management interfaces (device manager, Network Assistant, CLI) for protection against unauthorized configuration changes

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

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

BPDU guard for shutting down a Port Fast-configuredport 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-basedACLs for filteringnon-IPtraffic

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

IEEE 802.1x port-basedauthentication to prevent unauthorized devices (clients) from gaining access to the network. These features are supported:

VLAN assignment for restricting IEEE 802.1x-authenticatedusers to a specified VLAN

Port security for controlling access to IEEE 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

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Features

Guest VLAN to provide limited services to non-IEEE802.1x-compliantusers

IEEE 802.1x accounting to track network usage

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

SecureSocket Layer (SSL) Version 3.0 support for the HTTP1.1 server authentication, encryption, and message integrity, and HTTP client authentication to allow secure HTTP communications (requires the cryptographic version of the software)

QoS and CoS Features

Automatic QoS (auto-QoS)to simplify the deployment of existing QoS features by classifying traffic and configuring egress queues

Classification

IP type-of-service/DifferentiatedServices Code Point (IP ToS/DSCP) and IEEE 802.1p CoS marking priorities on aper-portbasis for protecting the performance ofmission-criticalapplications

IP ToS/DSCP and IEEE 802.1p CoS marking based on flow-basedpacket classification (classification based on information in the MAC, IP, and TCP/UDP headers) forhigh-performancequality of service at the network edge, allowing for differentiated service levels for different types of network traffic and for prioritizingmission-criticaltraffic 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-policingpolicies on the switch port for managing how much of the port bandwidth should be allocated to a specific traffic flow

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

Out-of-Profile

Out-of-profilemarkdown 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)

Weighted tail drop (WTD) as the congestion-avoidancemechanism 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 internal ring (sharing is the only supported mode on ingress queues)

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Chapter 1 Overview

Default Settings After Initial Switch Configuration

Egress queues and scheduling

Four egress queues per port

WTD as the congestion-avoidancemechanism 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.

Monitoring Features

Switch LEDs that provide portand switch-levelstatus

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

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

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-outevents

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 and 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-playoperation, 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 theinterface-specificandsystem-widesettings.

Note For information about assigning an IP address by using thebrowser-basedExpress Setup program, see the getting started guide. For information about assigning an IP address by using theCLI-basedsetup program, see the hardware installation guide.

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Chapter 1 Overview

Default Settings After Initial Switch Configuration

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,” andChapter 19, “Configuring DHCP 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,” andChapter 19, “Configuring DHCP Features.”

Switch cluster is disabled. For more information about switch clusters, see Chapter 5, “Clustering Switches,” and theGetting Started with Cisco Network Assistant, available on Cisco.com.

No passwords are defined. For more information, see Chapter 6, “Administering the Switch.”

System name and prompt is Switch. For more information, seeChapter 6, “Administering the Switch.”

NTP is enabled. For more information, see Chapter 6, “Administering the Switch.”

DNS is enabled. For more information, see Chapter 6, “Administering the Switch.”

TACACS+ is disabled. For more information, see Chapter 8, “Configuring Switch-Based Authentication.”

RADIUS is disabled. For more information, see Chapter 8, “Configuring Switch-Based Authentication.”

The standard HTTP server and Secure Socket Layer (SSL) HTTPS server are both enabled. For more information, see Chapter 8, “Configuring Switch-Based Authentication.”

IEEE 802.1x is disabled. For more information, see Chapter 9, “Configuring IEEE 802.1x Port-Based Authentication.”

Port parameters

Interface speed and duplex mode is autonegotiate. For more information, see Chapter 10, “Configuring Interface Characteristics.”

Auto-MDIXis enabled. For more information, seeChapter 10, “Configuring Interface Characteristics.”

Flow control is off. For more information, see Chapter 10, “Configuring Interface Characteristics.”

No Smartports macros are defined. For more information, see Chapter 11, “Configuring Smartports Macros.”

VLANs

Default VLAN is VLAN 1. For more information, see Chapter 12, “Configuring VLANs.”

VLAN trunking setting is dynamic auto (DTP). For more information, see Chapter 12, “Configuring VLANs.”

Trunk encapsulation is negotiate. For more information, see Chapter 12, “Configuring VLANs.”

VTP mode is server. For more information, see Chapter 13, “Configuring VTP.”

VTP version is Version 1. For more information, see Chapter 13, “Configuring VTP.”

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

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Default Settings After Initial Switch Configuration

For STP, PVST+ is enabled on VLAN 1. For more information, see Chapter 15, “Configuring STP.”

MSTP is disabled. For more information, see Chapter 16, “Configuring MSTP.”

Optional spanning-treefeatures are disabled. For more information, seeChapter 17, “Configuring Optional Spanning-Tree Features.”

Flex Links are not configured. For more information, see Chapter 18, “Configuring Flex Links.”

DHCP snooping is disabled. The DHCP snooping information option is enabled. For more information, see Chapter 19, “Configuring DHCP Features.”

IGMP snooping is enabled. No IGMP filters are applied. For more information, see Chapter 20, “Configuring IGMP Snooping and MVR.”

IGMP throttling setting is deny. For more information, see Chapter 20, “Configuring IGMP Snooping and MVR.”

The IGMP snooping querier feature is disabled. For more information, see Chapter 20, “Configuring IGMP Snooping and MVR.”

MVR is disabled. For more information, see Chapter 20, “Configuring IGMP Snooping and MVR.”

Port-basedtraffic

Broadcast, multicast, and unicast storm control is disabled. For more information, see Chapter 21, “Configuring Port-Based Traffic Control.”

No protected ports are defined. For more information, see Chapter 21, “Configuring Port-Based Traffic Control.”

Unicast and multicast traffic flooding is not blocked. For more information, see Chapter 21, “Configuring Port-Based Traffic Control.”

No secure ports are configured. For more information, see Chapter 21, “Configuring Port-Based Traffic Control.”

CDP is enabled. For more information, see Chapter 22, “Configuring CDP.”

UDLD is disabled. For more information, see Chapter 24, “Configuring UDLD.”

SPAN and RSPAN are disabled. For more information, see Chapter 23, “Configuring SPAN and RSPAN.”

RMON is disabled. For more information, see Chapter 25, “Configuring RMON.”

Syslog messages are enabled and appear on the console. For more information, see Chapter 26, “Configuring System Message Logging.”

SNMP is enabled (Version 1). For more information, see Chapter 27, “Configuring SNMP.”

No ACLs are configured. For more information, see Chapter 28, “Configuring Network Security with ACLs.”

QoS is disabled. For more information, see Chapter 29, “Configuring QoS.”

No EtherChannels are configured. For more information, see Chapter 30, “Configuring EtherChannels.”

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Chapter 1 Overview

Network Configuration Examples

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 1-11

“Small to Medium-Sized Network Using Catalyst 2960 Switches” section on page 1-14

“Long-Distance, High-Bandwidth Transport Configuration” section on page 1-15

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 they use.

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

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

segment and a growing number of

VLANs and IP subnets to place the network resources in the same logical network

users accessing the Internet

as the users who access those resources most.

 

 

Usefull-duplexoperation between the switch and its connected workstations.

 

 

Increased power of new PCs,

Connect globalresources—suchas servers and routers to which the network users

workstations, and servers

require equal access—directlyto thehigh-speedswitch ports so that they have

High bandwidth demand from

their own high-speedsegment.

 

networked applications (such as

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

e-mailwith large attached files)

routers.

and from bandwidth-intensive

 

applications (such as

 

multimedia)

 

 

 

 

 

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Chapter 1 Overview

Network Configuration Examples

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

Use IGMP snooping to efficiently forward multimedia and multicast traffic.

multimedia applications and

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

guaranteed bandwidth for critical

and congestion avoidance to classify traffic with the appropriate priority level,

applications

 

 

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

Use Hot Standby Router Protocol (HSRP) for cluster command switch

and availability to provide always on

redundancy.

mission-criticalapplications

Use VLAN trunks and BackboneFast fortraffic-loadbalancing on the uplink ports

 

 

 

 

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

 

 

traffic.

 

 

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 highor 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

Use the Catalyst Long-ReachEthernet (LRE) switches to provide up to 15 Mb of IP

infrastructure to transport data and

connectivity over existing infrastructure, such as existing telephone lines.

voice from a home or office to the

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

Internet or an intranet at higher

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

speeds

 

 

information.

 

 

 

 

 

You can use the switches to create the following:

Cost-effectiveGigabit-to-the-desktopforhigh-performanceworkgroups (Figure 1-1)—Forhigh-speedaccess to network resources, you can use Catalyst 2960 switches in the access layer to provide Gigabit Ethernet to the desktop. To prevent congestion, use QoS DSCP marking priorities on these switches. Forhigh-speedIP 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-performanceworkgroup, where the Catalyst 2960 switches are connected to Catalyst 3750 switches in the distribution layer. The second illustration is of ahigh-performanceworkgroup in a branch office, where the Catalyst 2960 switches are connected to a router in the distribution layer.

Each switch in this configuration provides users with a dedicated 1-Gbpsconnection to network resources. Using SFP modules also provides flexibility in media and distance options throughfiber-opticconnections.

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Chapter 1 Overview

Network Configuration Examples

Figure 1-1High-PerformanceWorkgroup(Gigabit-to-the-Desktop)

Catalyst 3750

switches

Access-layerCatalyst switches

89373

WAN

Cisco 2600

router

Access-layerCatalyst switches

89374

Server aggregation (Figure 1-2)—Youcan use the switches to interconnect groups of servers, centralizing physical security and administration of your network. Forhigh-speedIP 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, if required. 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 the switches, which have redundant Gigabit 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-opticconnections.

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Chapter 1 Overview

Network Configuration Examples

Figure 1-2Server Aggregation

Campus

core

Catalyst 6500 switches

Catalyst 3750 StackWise switch stacks

Access-layerCatalyst switches

Server racks

89376

Small to Medium-SizedNetwork Using Catalyst 2960 Switches

Figure 1-3 shows a configuration for a network of up to 500 employees. This network uses Catalyst 2960 switches withhigh-speedconnections to two routers. For network reliability and load balancing, this network has HSRP enabled on the routers. This ensures connectivity to the Internet, WAN, andmission-criticalnetwork resources in case one of the routers fails. The switches are using EtherChannel for load sharing.

The switches are connected to workstations, local servers, and IEEE 802.3af compliant and noncompliant powered devices (such as Cisco IP Phones). The server farm includes a call-processingserver running Cisco CallManager software. Cisco CallManager controls call processing, routing, and Cisco IP Phone features and configuration. The switches are interconnected through Gigabit interfaces.

This network uses VLANs to logically segment the network into well-definedbroadcast 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 routes the traffic to the destination VLAN. In this network, the routers are providing inter-VLANrouting. VLAN access control lists (VLAN maps) on the switch provideintra-VLANsecurity and prevent unauthorized users from accessing critical areas of the network.

In addition to inter-VLANrouting, the routers provide QoS mechanisms such as DSCP priorities to prioritize the different types of network traffic and to deliverhigh-prioritytraffic. If congestion occurs, QoS dropslow-prioritytraffic to allow delivery ofhigh-prioritytraffic.

For pre-standardand IEEE802.3af-compliantpowered devices connected to Catalyst PoE switches, IEEE 802.1p/Q QoS gives voice trafficforwarding-priorityover data traffic.

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Chapter 1 Overview

Network Configuration Examples

Catalyst PoE switch ports automatically detect any Cisco pre-standardand IEEE802.3af-compliantpowered devices that are connected. Each PoE switch port provides 15.4 W of power per port. The powered device, such as a Cisco IP Phone, can receive redundant power when it is also connected to an AC power source. Powered devices not connected to Catalyst PoE switches must be connected to AC power sources to receive power.

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.

Figure 1-3Catalyst 2960 Switches in a Collapsed Backbone Configuration

Internet

Cisco 2600 or 3700 routers

Gigabit servers

IP

IP

 

Cisco IP

 

Aironet wireless

Workstations

access points

 

phones

running Cisco SoftPhone

software

101388

Long-Distance,High-BandwidthTransport Configuration

Figure 1-4 shows a configuration for sending 8 Gigabits of data over a singlefiber-opticcable. The Catalyst 2960 switches have coarsewavelength-divisionmultiplexing (CWDM)fiber-opticSFP 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 forlong-distancetransmissions is 1550 nm.

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 samefiber-opticcable. The CWDM OADM modules on the receiving end separate (ordemultiplex) 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.

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Chapter 1 Overview

Where to Go Next

Figure 1-4Long-Distance,High-BandwidthTransport Configuration

Access layer

Aggregation layer

 

8 Gbps

CWDM

CWDM

OADM

OADM

modules

modules Catalyst 4500

Eight

multilayer

1-Gbps

switches

connections

 

95750

Catalyst switches

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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C H A P T E R 2

Using the Command-LineInterface

This chapter describes the Cisco IOS command-lineinterface (CLI) and how to use it to configure your Catalyst 2960 switch. 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 Command History, page 2-5

Using Editing Features, page 2-6

Searching and Filtering Output of show and more Commands, page 2-9

Accessing the CLI, page 2-9

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-timecommands, such asshow commands, which show the current configuration status, andclear 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.

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 hostnameSwitch.

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Chapter 2 Using the Command-LineInterface

Understanding Command Modes

Table 2-1

Command Mode Summary

 

 

 

 

 

 

 

 

 

 

Mode

 

Access Method

Prompt

Exit Method

About This Mode

 

 

 

 

 

 

User EXEC

 

Begin a session with

Switch>

Enter logout or

Use this mode to

 

 

your switch.

 

quit.

Change terminal settings.

 

 

 

 

 

 

 

 

 

 

Perform basic tests.

 

 

 

 

 

Display system

 

 

 

 

 

 

information.

 

 

 

 

 

Privileged EXEC

While in user EXEC

Switch#

Enter disable to

Use this mode to verify

 

 

mode, enter the

 

exit.

commands that you have

 

 

enable command.

 

 

entered. Use a password to

 

 

 

 

 

protect access to this mode.

 

 

 

 

 

Global configuration

While in privileged

Switch(config)#

To exit to privileged

Use this mode to configure

 

 

EXEC mode, enter

 

EXEC mode, enter

parameters that apply to the

 

 

the configure

 

exit orend, or press

entire switch.

 

 

command.

 

Ctrl-Z.

 

 

 

 

 

 

 

 

Config-vlan

 

While in global

Switch(config-vlan)#

To exit to global

Use this mode to configure

 

 

configuration mode,

 

configuration mode,

VLAN parameters. When VTP

 

 

enter the

 

enter the exit

mode is transparent, you can

 

 

vlan vlan-id

 

command.

create extended-rangeVLANs

 

 

command.

 

To return to

(VLAN IDs greater than 1005)

 

 

 

 

and save configurations in the

 

 

 

 

privileged EXEC

 

 

 

 

switch startup configuration

 

 

 

 

mode, press Ctrl-Z

 

 

 

 

file.

 

 

 

 

 

or enter end.

 

 

 

 

 

 

 

 

 

 

 

 

VLAN configuration

While in privileged

Switch(vlan)#

To exit to privileged

Use this mode to configure

 

 

EXEC mode, enter

 

EXEC mode, enter

VLAN parameters for VLANs

 

 

the vlan database

 

exit.

1 to 1005 in the VLAN

 

 

command.

 

 

database.

 

 

 

 

 

 

 

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Chapter 2 Using the Command-LineInterface

Understanding the Help System

Table 2-1

Command Mode Summary (continued)

 

 

 

 

 

 

 

 

Mode

 

Access Method

Prompt

Exit Method

About This Mode

 

 

 

 

 

 

Interface

 

While in global

Switch(config-if)#

To exit to global

Use this mode to configure

configuration

 

configuration mode,

 

configuration mode,

parameters for the Ethernet

 

 

enter the interface

 

enter exit.

ports.

 

 

command (with a

 

To return to

For information about defining

 

 

specific interface).

 

 

 

 

privileged EXEC

interfaces, see the “Using

 

 

 

 

 

 

 

 

mode, press Ctrl-Z

Interface Configuration Mode”

 

 

 

 

or enter end.

section on page 10-4.

 

 

 

 

 

To configure multiple

 

 

 

 

 

interfaces with the same

 

 

 

 

 

parameters, see the

 

 

 

 

 

“Configuring a Range of

 

 

 

 

 

Interfaces” section on

 

 

 

 

 

page 10-6.

 

 

 

 

 

Line configuration

While in global

Switch(config-line)#

To exit to global

Use this mode to configure

 

 

configuration mode,

 

configuration mode,

parameters for the terminal

 

 

specify a line with

 

enter exit.

line.

 

 

the line vtyor line

 

To return to

 

 

 

console command.

 

 

 

 

 

privileged EXEC

 

 

 

 

 

 

 

 

 

 

mode, press Ctrl-Z

 

 

 

 

 

or enter end.

 

 

 

 

 

 

 

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 2-2Help 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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Understanding Abbreviated Commands

Table 2-2Help 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 theno form to disable a feature or function or reverse the action of a command. For example, theno shutdown interface configuration command reverses the shutdown of an interface. Use the command without the keywordno tore-enablea disabled feature or to enable a feature that is disabled by default.

Configuration commands can also have a default form. Thedefault form of a command returns the command setting to its default. Most commands are disabled by default, so thedefault form is the same as theno form. However, some commands are enabled by default and have variables set to certain default values. In these cases, thedefault command enables the command and sets variables to their default values.

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Chapter 2 Using the Command-LineInterface

Understanding CLI Error Messages

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:

You did not enter enough characters

Re-enterthe command followed by a question mark (?)

"show con"

 

for your switch to recognize the

with a space between the command and the question

 

 

command.

mark.

 

 

 

The possible keywords that you can enter with the

 

 

 

command appear.

 

 

 

% Incomplete command.

You did not enter all the keywords or

Re-enterthe command followed by a question mark (?)

 

 

values required by this command.

with a space between the command and the question

 

 

 

mark.

 

 

 

The possible keywords that you can enter with the

 

 

 

command appear.

 

 

 

% Invalid input detected

You entered the command

Enter a question mark (?) to display all the commands

at ‘^’ marker.

 

incorrectly. The caret (^) marks the

that are available in this command mode.

 

 

point of the error.

The possible keywords that you can enter with the

 

 

 

 

 

 

command appear.

 

 

 

 

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 2-5 (optional)

Recalling Commands, page 2-6 (optional)

Disabling the Command History Feature, page 2-6 (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[sizenumber-of-lines]

The range is from 0 to 256.

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Chapter 2 Using the Command-LineInterface

Using Editing Features

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

 

 

 

 

Action1

 

Result

Press Ctrl-P or the up arrow key.

Recall commands in the history buffer, beginning with the most recent command.

 

 

Repeat the key sequence to recall successively older commands.

 

 

Press Ctrl-N or the down arrow key.

Return to more recent commands in the history buffer after recalling commands

 

 

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

 

 

more recent commands.

 

 

 

show history

 

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

 

 

entered. The number of commands that appear is controlled by the setting of the

 

 

terminal history global configuration command and thehistory line configuration

 

 

command.

 

 

 

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

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 2-7 (optional)

Editing Command Lines that Wrap, page 2-8 (optional)

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Chapter 2 Using the Command-LineInterface

Using Editing Features

Enabling and Disabling Editing Features

Although enhanced editing mode is automatically enabled, you can disable it, re-enableit, 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-enablethe 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

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

 

 

 

 

 

Capability

 

Keystroke1

Purpose

Move around the command line to

Press Ctrl-B,or press the

Move the cursor back one character.

make changes or corrections.

left arrow key.

 

 

 

 

 

 

 

Press Ctrl-F,or press the

Move the cursor forward one character.

 

 

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

 

 

 

character located at the cursor.

 

 

 

Recall commands from the buffer

Press Ctrl-Y.

Recall the most recent entry in the buffer.

and 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.

 

 

 

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.

 

 

 

Delete entries if you make a mistake

Press the Delete or

Erase the character to the left of the cursor.

or change your mind.

Backspace key.

 

 

 

 

 

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Chapter 2 Using the Command-LineInterface

Using Editing Features

Table 2-5

Editing Commands through Keystrokes (continued)

 

 

 

 

Capability

 

Keystroke1

Purpose

 

 

Press Ctrl-D.

Delete the character at the cursor.

 

 

 

 

 

 

Press Ctrl-K.

Delete all characters from the cursor to the end of the

 

 

 

command line.

 

 

 

 

 

 

Press Ctrl-Uor Ctrl-X.

Delete all characters from the cursor to the beginning of

 

 

 

the command line.

 

 

 

 

 

 

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-Vor Esc Q.

 

an executable command, perhaps as a

 

 

shortcut.

 

 

 

 

 

 

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 Spacebar

 

 

keystrokes whenever you see

 

 

the More prompt.

 

 

 

 

 

 

 

 

Press the Space bar.

Scroll down one screen.

 

 

 

Redisplay the current command line

Press Ctrl-Lor 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-compatibleterminals such as VT100s.

Editing Command Lines that Wrap

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 pressCtrl-A to immediately move to the beginning of the line.

Note The arrow keys function only onANSI-compatibleterminals such as VT100s.

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Chapter 2 Using the Command-LineInterface

Searching and Filtering Output of show and more Commands

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-list101 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 theReturn 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-list101 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 2-7.

Searching and Filtering Output of show and more Commands

You can search and filter the output for show andmore 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 ormore command followed by thepipe character (|), one of the keywordsbegin,include, orexclude, 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 containoutput are not displayed, but the lines that containOutput 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

GigabitEthernet0/1 is up, line protocol is down

GigabitEthernet0/2 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.

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Accessing the CLI

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 hardware installation 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.”

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 8-6.

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-upmodem. For information about connecting to the console port, see the switch 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 8-6.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 8-33.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.

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C H A P T E R 3

Assigning the Switch IP Address and Default

Gateway

This chapter describes how to create the initial switch configuration (for example, assigning the switch IP address and default gateway information) for the Catalyst 2960 switch by using a variety of automatic and manual methods. It also describes how to modify the switch startup configuration.

Note For complete syntax and usage information for the commands used in this chapter, see the command reference for this release and to theCisco IOS IP Command Reference, Volume 1 of 3: Addressing and Services, Release 12.2.

This chapter consists of these sections:

Understanding the Boot Process, page 3-1

Assigning Switch Information, page 3-2

Checking and Saving the Running Configuration, page 3-10

Modifying the Startup Configuration, page 3-11

Scheduling a Reload of the Software Image, page 3-15

Understanding the Boot Process

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

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

Performs low-levelCPU initialization. It initializes the CPU registers, which control where physical memory is mapped, its quantity, its speed, and so forth.

Performs power-onself-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.

Initializes the flash file system on the system board.

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

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Assigning Switch Information

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-dooraccess into the system if the operating system has problems serious enough that it cannot be used. Thetrap-doormechanism 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 31-2 and the“Recovering from a Lost or Forgotten Password” section on page 31-3.

Note You can disable password recovery. For more information, see the“Disabling Password Recovery” section on page 8-5.

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-emulationsoftware 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.

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.

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.

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Assigning Switch Information

These sections contain this configuration information:

Default Switch Information, page 3-3

Understanding DHCP-Based Autoconfiguration, page 3-3

Manually Assigning IP Information, page 3-9

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-assigneddefault hostname isSwitch.

 

 

Telnet password

No password is defined.

 

 

Cluster command switch functionality

Disabled.

 

 

 

Cluster name

 

No cluster name is defined.

 

 

 

Understanding DHCP-BasedAutoconfiguration

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

With DHCP-basedautoconfiguration, no DHCPclient-sideconfiguration 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.

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-basedautoconfiguration replaces the BOOTP client functionality on your switch.

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Assigning Switch Information

DHCP Client Request Process

When you boot 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 3-1DHCP Client and Server Message Exchange

DHCPDISCOVER (broadcast)

Switch A

 

DHCPOFFER (unicast)

 

 

 

 

 

 

 

 

 

 

DHCPREQUEST (broadcast)

 

 

 

 

 

 

 

 

 

 

DHCPACK (unicast)

 

 

 

 

 

 

 

DHCP server

51807

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.

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 3-5.

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 client; 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.

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Assigning Switch Information

Configuring DHCP-BasedAutoconfiguration

These sections contain this configuration information:

DHCP Server Configuration Guidelines, page 3-5

Configuring the TFTP Server, page 3-5

Configuring the DNS, page 3-6

Configuring the Relay Device, page 3-6

Obtaining Configuration Files, page 3-7

Example Configuration, page 3-8

If your DHCP server is a Cisco device, see the “Configuring DHCP” section of the “IP Addressing and Services” section of the Cisco IOS IP Configuration Guide, Release 12.2 for additional information about configuring DHCP.

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:

IP address of the client (required)

Subnet mask of the client (required)

DNS server IP address (optional)

Router IP address (default gateway address to be used by the switch) (required)

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.

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.

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Assigning Switch Information

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, orhostname.cfg, wherehostname 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:

The configuration file named in the DHCP reply (the actual switch configuration file).

The network-confgor the cisconet.cfg file (known as the default configuration files).

The router-confgor the ciscortr.cfg file (These files contain commands common to all switches. Normally, if the DHCP and TFTP servers are properly configured, these files are not accessed.)

If you specify the TFTP server name in the DHCP server-leasedatabase, you must also configure the TFTP servername-to-IP-addressmapping in theDNS-serverdatabase.

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 3-6.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-IPaddress 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.

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)# iphelper-address20.0.0.2

 

 

 

router(config-if)# iphelper-address20.0.0.3

 

 

 

router(config-if)# iphelper-address20.0.0.4

 

 

 

On interface 20.0.0.1

 

 

 

router(config-if)# iphelper-address10.0.0.1

 

 

 

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Figure 3-2Relay Device Used in Autoconfiguration

 

Switch

Cisco router

(DHCP client)

 

(Relay)

 

 

 

 

 

 

 

10.0.0.1

10.0.0.2

 

20.0.0.1

 

 

 

 

 

 

 

 

20.0.0.2

20.0.0.3

20.0.0.4

DHCP server

TFTP server

DNS server

49068

Obtaining Configuration Files

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-fileread 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-upprocess.

The IP address and the configuration filename is reserved for the switch, but the TFTP server address is not provided in the DHCP reply (one-fileread 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-upprocess.

Only the IP address is reserved for the switch and provided in the DHCP reply. The configuration filename is not provided (two-fileread 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-confgor cisconet.cfg default configuration file. (If thenetwork-confgfile cannot be read, the switch reads the cisconet.cfg file.)

The default configuration file contains the hostnames-to-IP-addressmapping 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 defaultSwitch 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-confgorhostname.cfg, depending on whethernetwork-confgor 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 therouter-confgfile. If the switch cannot read therouter-confgfile, it reads the ciscortr.cfg file.

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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 usingDHCP-basedautoconfiguration.

Figure 3-3DHCP-BasedAutoconfiguration Network Example

Switch 1

 

Switch 2

 

Switch 3

 

Switch 4

00e0.9f1e.2001

00e0.9f1e.2002

00e0.9f1e.2003

00e0.9f1e.2004

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cisco router

10.0.0.10

10.0.0.1

10.0.0.2

10.0.0.3

DHCP server

DNS server

TFTP server

 

 

(tftpserver)

111394

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

tftpserver or

tftpserver or

tftpserver or

 

 

10.0.0.3

10.0.0.3

10.0.0.3

10.0.0.3

 

 

 

 

 

Boot filename (configuration file)

switcha-confg

switchb-confg

switchc-confg

switchd-confg

(optional)

 

 

 

 

 

 

 

 

 

 

Hostname (optional)

switcha

switchb

switchc

switchd

 

 

 

 

 

 

DNS Server Configuration

The DNS server maps the TFTP server name tftpserver to IP address 10.0.0.3.

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TFTP Server Configuration (on UNIX)

The TFTP server base directory is set to /tftpserver/work/. This directory contains the network-confgfile used in thetwo-fileread 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-confgswitcha-confgswitchb-confgswitchc-confgswitchd-confg

prompt> catnetwork-confgip 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.

If no configuration filename is given in the DHCP server reply, Switch A reads the network-confgfile from the base directory of the TFTP server.

It adds the contents of the network-confgfile 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.

Switches B through D retrieve their configuration files and IP addresses in the same way.

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

 

 

configure terminal

Enter global configuration mode.

Step 2

 

 

interface vlan vlan-id

Enter interface configuration mode, and enter the VLAN to which the IP

 

 

information is assigned. The range is 1 to 4094.

Step 3

 

 

ip address ip-addresssubnet-mask

Enter the IP address and subnet mask.

Step 4

 

 

exit

Return to global configuration mode.

 

 

 

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Command

Purpose

Step 5

 

 

ip default-gatewayip-address

Enter the IP address of the next-hoprouter 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

 

 

to have a default gateway set.

Step 6

 

 

end

Return to privileged EXEC mode.

Step 7

 

 

show interfaces vlan vlan-id

Verify the configured IP address.

Step 8

 

 

show ip redirects

Verify the configured default gateway.

Step 9

 

 

copy running-configstartup-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 theno 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 6, “Administering the Switch.”

Checking and Saving the Running Configuration

You can check the configuration settings you entered or changes you made by entering this privileged EXEC command:

Switch# showrunning-config

Building configuration...

Current configuration: 1363 bytes

!

version 12.1 no service pad

service timestamps debug uptime service timestamps log uptime no service password-encryption

!

hostname Switch A

!

enable secret 5 $1$ej9.$DMUvAUnZOAmvmgqBEzIxE0

!

.

<output truncated>

.

interface gigabitethernet0/1

ip address 172.20.137.50 255.255.255.0

!

interface gigabitethernet0/2 mvr type source

<output truncated>

...!

interface VLAN1

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ip address 172.20.137.50 255.255.255.0 no ip directed-broadcast

!

ip default-gateway172.20.137.1 !

!

snmp-servercommunity private RWsnmp-servercommunity public ROsnmp-servercommunity private@es0 RWsnmp-servercommunity public@es0 ROsnmp-serverchassis-id0x12

!

end

To store the configuration or changes you have made to your startup configuration in flash memory, enter this privileged EXEC command:

Switch# copyrunning-configstartup-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 ormore 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.”

Modifying the Startup Configuration

These sections describe how to modify the switch startup configuration:

Default Boot Configuration, page 3-12

Automatically Downloading a Configuration File, page 3-12

Booting Manually, page 3-13

Booting a Specific Software Image, page 3-13

Controlling Environment Variables, page 3-14

See also Appendix B, “Working with the Cisco IOS File System, Configuration Files, and Software Images,” for information about switch configuration files.

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Default Boot Configuration

Table 3-3 shows the default boot configuration.

Table 3-3

Default Boot Configuration

 

 

 

Feature

 

Default Setting

 

 

Operating system software image

The switch attempts to automatically boot 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-firstsearch

 

 

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-firstsearch 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

You can automatically download a configuration file to your switch by using the DHCP-basedautoconfiguration feature. For more information, see the“Understanding DHCP-Based Autoconfiguration” section on page 3-3.

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 cycle.

Beginning in privileged EXEC mode, follow these steps to specify a different configuration filename:

 

 

Command

Purpose

 

 

 

 

 

 

 

Step 1

configure terminal

Enter global configuration mode.

 

 

 

 

 

 

 

Step 2

boot config-fileflash:/file-url

Specify the configuration file to load during the next boot cycle.

 

 

 

 

 

For file-url,specify the path (directory) and the configuration

 

 

 

 

 

filename.

 

 

 

 

 

Filenames and directory names are case sensitive.

 

 

 

 

 

 

 

Step 3

end

Return to privileged EXEC mode.

 

 

 

 

 

 

 

Step 4

show boot

Verify your entries.

 

 

 

 

 

The boot config-file global configuration command changes the

 

 

 

 

 

setting of the CONFIG_FILE environment variable.

 

 

 

 

 

 

 

Step 5

copy running-configstartup-config

(Optional) Save your entries in the configuration file.

 

 

 

 

 

 

 

 

 

 

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Modifying the Startup Configuration

To return to the default setting, use the no boot config-file global configuration command.

Booting Manually

By default, the switch automatically boots; however, you can configure it to manually boot.

Beginning in privileged EXEC mode, follow these steps to configure the switch to manually boot during the next boot cycle:

 

Command

Purpose

Step 1

 

 

configure terminal

Enter global configuration mode.

Step 2

 

 

boot manual

Enable the switch to manually boot during the next boot cycle.

Step 3

 

 

end

Return to privileged EXEC mode.

Step 4

 

 

show boot

Verify your entries.

 

 

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 the system, use the

 

 

boot filesystem:/file-url boot loader command.

 

 

Forfilesystem:, useflash: for the system board flash device.

 

 

Forfile-url,specify the path (directory) and the name of the

 

 

bootable image.

 

 

Filenames and directory names are case sensitive.

Step 5

 

 

copy running-configstartup-config

(Optional) Save your entries in the configuration file.

 

 

 

To disable manual booting, use the no boot manual global configuration command.

Booting a Specific Software Image

By default, the switch attempts to automatically boot 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-firstsearch throughout the flash file system. In adepth-firstsearch 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.

Beginning in privileged EXEC mode, follow these steps to configure the switch to boot a specific image during the next boot cycle:

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Command

Purpose

Step 1

 

 

configure terminal

Enter global configuration mode.

Step 2

 

 

boot system filesystem:/file-url

Configure the switch to boot a specific image in flash memory during the

 

 

next boot cycle.

 

 

Forfilesystem:, useflash: for the system board flash device.

 

 

Forfile-url,specify the path (directory) and the name of the bootable

 

 

image.

 

 

Filenames and directory names are case sensitive.

Step 3

 

 

end

Return to privileged EXEC mode.

Step 4

 

 

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 the

 

 

system using information in the BOOT environment variable.

Step 5

 

 

copy running-configstartup-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 bps. Unplug the switch power cord, and press the switch Mode button while reconnecting the power cord. You can release theMode button a second or two after the LED above port 1 turns off. Then the boot loaderswitch: prompt appears.

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.

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Scheduling a Reload of the Software Image

Note For complete syntax and usage information for the boot loader commands and environment variables, see the command reference for this release.

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 ...

boot system filesystem:/file-url ...

 

 

A semicolon-separatedlist of executable files to

Specifies the Cisco IOS image to load during the

 

 

try to load and execute when automatically

next boot cycle. This command changes the

 

 

booting. If the BOOT environment variable is not

setting of the BOOT environment variable.

 

 

set, the system attempts to load and execute the

 

 

 

first executable image it can find by using a

 

 

 

recursive, depth-firstsearch 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

boot manual

 

 

Decides whether the switch automatically or

Enables manually booting the switch during the

 

 

manually boots.

next boot cycle and changes the setting of the

 

 

Valid values are 1, yes, 0, and no. If it is set to no

MANUAL_BOOT environment variable.

 

 

or 0, the boot loader attempts to automatically

The next time you reboot the system, the switch is

 

 

boot the system. If it is set to anything else, you

in boot loader mode. To boot the system, use the

 

 

must manually boot the switch from the boot

boot flash:filesystem:/file-urlboot loader

 

 

loader mode.

command, and specify the name of the bootable

 

 

 

image.

 

 

 

CONFIG_FILE

set CONFIG_FILE flash:/file-url

boot config-fileflash:/file-url

 

 

Changes the filename that Cisco IOS uses to read

Specifies the filename that Cisco IOS uses to read

 

 

and write a nonvolatile copy of the system

and write a nonvolatile copy of the system

 

 

configuration.

configuration. This command changes the

 

 

 

CONFIG_FILE environment variable.

 

 

 

 

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.

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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.

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