Cisco Catalyst 2960, Catalyst 2960-S Software Configuration Manual

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Page 1

INDEX

abbreviating commands 2-3

AC (command switch) 6-9

access-class command 31-18

access control entries

See ACEs

access control entry (ACE)

access-denied response, VMPS 13-24

access groups

Layer 3

31-19

access groups, applying IPv4 ACLs to interfaces 31-19

accessing

clusters, switch

6-12

command switches 6-10

member switches 6-12

switch clusters 6-12

accessing stack members 7-22

access lists

See ACLs

access ports

in switch clusters

access ports, defined 12-3

accounting

with 802.1x

10-51

with IEEE 802.1x 10-16

with RADIUS 9-35

with TACACS+ 9-11, 9-17

ACEs

and QoS

33-8

defined 31-2

Ethernet 31-2

IP 31-2

37-3

6-8

ACLs

ACEs

31-2

any keyword 31-10

applying

time ranges to

31-15

to an interface 31-18, 37-7

to IPv6 interfaces 37-7

to QoS 33-8

classifying traffic for QoS 33-50

comments in 31-17

compiling 31-21

defined 31-1, 31-7

examples of 31-21, 33-50

extended IP, configuring for QoS classification 33-51

extended IPv4

creating

31-9

matching criteria 31-7

hardware and software handling 31-20

host keyword 31-11

creating

31-7

fragments and QoS guidelines 33-40

implicit deny 31-9, 31-13, 31-14

implicit masks 31-9

matching criteria 31-7

undefined 31-19

IPv4

applying to interfaces

31-18

creating 31-7

matching criteria 31-7

named 31-13

numbers 31-7

terminal lines, setting on 31-18

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Index

unsupported features 31-6

IPv6

applying to interfaces

37-7

configuring 37-3, 37-4

displaying 37-8

interactions with other features 37-4

limitations 37-2, 37-3

matching criteria 37-3

named 37-2

precedence of 37-2

supported 37-2

unsupported features 37-3

MAC extended 31-23, 33-52

matching 31-7, 31-19, 37-3

monitoring 31-26, 37-8

named, IPv4 31-13

named, IPv6 37-2

names 37-4

number per QoS class map 33-40

port 31-2, 37-1

precedence of 31-2

QoS 33-8, 33-50

resequencing entries 31-13

router 31-2, 37-1

standard IP, configuring for QoS classification 33-50

standard IPv4

creating

31-8

matching criteria 31-7

support for 1-10

support in hardware 31-20

time ranges 31-15

types supported 31-2

unsupported features, IPv4 31-6

unsupported features, IPv6 37-3

active link 19-4, 19-5, 19-6

active links 19-2

active traffic monitoring, IP SLAs 32-1

address aliasing 21-2

addresses

displaying the MAC address table

5-24

dynamic

accelerated aging

16-9

changing the aging time 5-15

default aging 16-9

defined 5-13

learning 5-14

removing 5-16

IPv6 35-2

MAC, discovering 5-24

multicast, STP address management 16-9

static

adding and removing

5-20

defined 5-13

address resolution 5-24

Address Resolution Protocol

See ARP

Audience

Preface

This guide is for the networking professional managing the Catalyst 2960, 2960-S, and 2960-C 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.

Catalyst 2960, 2960-S, and 2960-C switches run one of these images:

• The LAN base software image provides enterprise-class intelligent services such as access control

lists (ACLs) and quality of service (QoS) features. On a Catalyst 2960-S switch, stacking is also supported.

• The LAN Lite image provides reduced functionality.

The Catalyst 2960-S ships with a universal image that includes cryptographic functionality. The software image on the switch is either the LAN base or LAN Lite image, depending on the switch model. To determine which image your switch is running:

• Switches running the LAN Lite image do not support the FlexStack module. They do not have a

FlexStack module slot on the rear of the switch.

• On the front of the switch, the label in the top right corner ends in -S if the switch model runs the

LAN Lite image.

• Enter the show version privileged EXEC command. The line that shows the product ID also ends in

either -L (if running the LAN base image) or -S (if running the LAN Lite image). For example, WS-C2960S-48PD-L is running LAN base; WS-C2960S-24TS-S is running LAN Lite image.

• Enter the show license privileged EXEC command, and see which is the active image:

Switch# show license Index 1 Feature: lanlite Period left: 0 minute 0 second

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Preface

Index 2 Feature: lanbase Period left: Life time License Type: Permanent License State: Active, In Use License Priority: Medium License Count: Non-Counted

This guide provides procedures for using the commands that have been created or changed for use with the switch. It does not provide detailed information about these commands. For detailed information about these commands, see the Catalyst 2960, 2960-S, and 2960-C Switch Command Reference for this release. For information about the standard Cisco IOS Release 15.0 commands, see the Cisco IOS documentation set available on Cisco.com.

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

This guide does not describe system messages you might encounter or how to install your switch. For more information, see the appropriate system message guide and hardware installation guide.

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

Conventions

This publication uses these conventions to convey instructions and information:

Command descriptions use these conventions:

Interactive examples use these conventions:

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

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

this manual.

• 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.

• 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 (< >).

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

damage or loss of data.

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Preface

Related Publications

These documents provide complete information about the switch and are available from this Cisco.com site: http://www.cisco.com/en/US/products/ps6406/tsd_products_support_series_home.html

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

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

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

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

orderable but available on Cisco.com).

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

orderable but available on Cisco.com).

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

available on Cisco.com).

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

See these documents for other information about the switch:

• Release Notes for the Catalyst 3750, 3560, 3560-C, 2960, 2960-S, and 2960- C Switches

•

• Release Notes for the Catalyst 2960-S switches

• Catalyst 2960 Switch Getting Started Guide

• Catalyst 2960-S Switch Getting Started Guide

• Catalyst 3560-C and 2960-C Switch Hardware Installation Guide

• Catalyst 2960, 2960-S, and 2960-C Switch Software Configuration Guide

• Catalyst 2960, 2960-S, and 2960-C Switch Command Reference

• Catalyst 2960 Switch Hardware Installation Guide

• Catalyst 2960-S Switch Hardware Installation Guide

• Catalyst 3560-C and 2960-C Switch Hardware Installation Guide

• Regulatory Compliance and Safety Information for the Catalyst 2960 and 2960-S Switch

• Regulatory Compliance and Safety Information for the Catalyst 3560-C and 2960-C Switch

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

• Auto Smartports Configuration Guide

• Call Home Configuration Guide

• Cisco EnergyWise Configuration Guide

• Smart Install Configuration Guide

• Release Notes for Cisco Network Assistant

• Getting Started with Cisco Network Assistant

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• Cisco CWDM GBIC and CWDM SFP Installation Note

• Cisco RPS 300 Redundant Power System Hardware Installation Guide

• Cisco RPS 675 Redundant Power System Hardware Installation Guide

• Cisco Redundant Power System 2300 Hardware Installation Guide

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

Control Software Configuration Guide

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

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

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

http://www.cisco.com/en/US/products/hw/modules/ps5455/products_device_support_tables_list.ht ml

Obtaining Documentation, Obtaining Support, and Security Guidelines

Preface

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

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

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

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Features

CHA P T E R

Overview

This chapter provides these topics about the Catalyst 2960, 2960-S and 2960-C switch software:

• Features, page 1-1

• Default Settings After Initial Switch Configuration, page 1-17

• Network Configuration Examples, page 1-19

• Where to Go Next, page 1-26

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

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

The switch supports a LAN base image or a LAN lite image with a reduced feature set, depending on switch hardware.

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

• Performance Features, page 1-4

• Management Options, page 1-5

• Manageability Features, page 1-6

• Availability and Redundancy Features, page 1-8

• VLAN Features, page 1-9

• Security Features, page 1-10

• QoS and CoS Features, page 1-13

• Power over Ethernet Features, page 1-15

• Universal Power over Ethernet Features, page 1-15

• Monitoring Features, page 1-16

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

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

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

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

simplified deployment across the network.

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

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

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

–

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

–

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

–

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

Chapter 1 Overview

–

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

Note If the switch is running the LAN Lite image, you can configure ACLs, but you cannot attach

them to interfaces or VLANs.

–

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

–

Downloading an image to a switch.

–

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

–

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

–

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

Note To use the RPS, the switch must be running the LAN Base image.

1-2

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

• Cisco FlexStack technology on Catalyst 2960-S switches running the LAN base image for

–

Connecting up to four switches through their FlexStack ports to operate as a single switch in the network.

–

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

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Chapter 1 Overview

–

Creating a bidirectional 20-Gb/s switching fabric across the switch stack, with all stack members having full access to the system bandwidth.

–

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

–

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

–

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

–

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

–

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

• Switch clustering technology for

–

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

Features

–

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

–

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

• Stack troubleshooting enhancements

• Auto Smartports

–

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

–

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

–

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

–

Auto Smartports enhancement to enable auto-QoS on a CDP-capable Cisco digital media player.

–

Improved device classification capabilities and accuracy, increased device visibility, and enhanced macro management. The device classifier is enabled by default, and can classify devices based on DHCP options.

For information, see the Auto Smartports Configuration Guide.

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

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

Smart Install Configuration Guide.

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Features

–

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

–

Smart Install enhancements in Cisco IOS Release 12.2(58)SE including the ability to manually change a client switch health state from denied to allowed or hold for on-demand upgrades, to remove selected clients from the director database, to allow simultaneous on-demand upgrade of multiple clients, and to provide more information about client devices, including device status, health status, and upgrade status.

• Call Home to provide e-mail-based and web-based notification of critical system events. Users with

a service contract directly with Cisco Systems can register Call Home devices for the Cisco Smart Call Home service that generates automatic service requests with the Cisco TAC.

Performance Features

• Cisco EnergyWise manages the energy usage of endpoints connected to domain members. For more

information, see the Cisco EnergyWise documentation on Cisco.com.

• EnergyWise Phase 2.5 enhancements that add support for a query to analyze and display domain

information and for Wake on LAN (WoL) to remotely power on a WoL-capable PC.

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

bandwidth.

Chapter 1 Overview

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

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

• SFP+ support for 10Gigabit speeds (Catalyst 2960-S only)

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

that are bridged by software

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

• Up to 20 Gb/s of forwarding rates in a Catalyst 2960-S switch stack.

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

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

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

creation of EtherChannel links.

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

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

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

traffic.

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

efficiently forwarding multimedia and multicast traffic

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

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

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

messages.

1-4

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Chapter 1 Overview

Features

• IPv6 host support for basic IPv6 management

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

multicast data to clients and routers in a switched network

Note To use IPv6 features, the switch must be running the LAN Base image.

• 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.

Note To use MVR, the switch must be running the LAN Base image.

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

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

forwarding table.

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

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

support for user-selected features.

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

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

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

Link failure.

Note To use Flex Link Multicast Fast Convergence, the switch must be running the LAN Base image.

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

across a server group.

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

network ports.

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

memory (TCAM) table entries.

Management Options

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

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

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

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

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

the CLI by connecting your management station directly to the switch console port, by connecting your PC directly to the Ethernet management port, or by using Telnet from a remote management

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Features

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

the Command-Line Interface.”

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

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

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

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

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

Manageability Features

Chapter 1 Overview

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

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

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

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

requests, from DHCP clients

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

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

image to a large number of switches

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

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

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

• 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

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

the size of the MAC address table

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

between the switch and other Cisco devices on the network

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

interoperability with third-party IP phones

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

switch to the endpoint device

1-6

Note To use LLDP-MED, the switch must be running the LAN Base image.

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Chapter 1 Overview

Features

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

points for dynamic location-based content distribution from servers

• Network Time Protocol (NTP) version 4 for NTP time synchronization for both IPv4 and IPv6

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

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

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

user EXEC command display

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

Internet Explorer browser session

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

sessions over the network

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

for multiple CLI-based sessions over the network

• Support for SSH for IPv6.

• Support for IPv6 Host on the LAN Base and LAN Lite image (Catalyst 2960 and 2960-S).

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

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

to a remote terminal through a serial connection or a modem

• Out-of-band management access through the Ethernet management port to a PC (Catalyst

2960-only)

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

switch configuration or switch image files (requires the cryptographic version of the software) for both IPv4 and IPv6

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

saved Cisco IOS configuration file

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

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

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

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

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

management of host and mobile IP addresses

• Disabling MAC address learning on a VLAN

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

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

a Cisco Mobility Services Engine (MSE)

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Note To use wired location, the switch must be running the LAN Base image.

• CPU utilization threshold trap monitors CPU utilization

Note To use CPU utilization, the switch must be running the LAN Base image.

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Features

Chapter 1 Overview

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

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

Note Supported on all images in Cisco IOS Release 12.2(55)SE and later.

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

identical configuration files to be sent by using the DHCP protocol

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

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

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

based on the power policy TLV request

• USB mini-Type B console port in addition to the standard RJ-45 console port. Console input is

active on only one port at a time. (Catalyst 2960-S only)

• USB Type A port for external Cisco USB flash memory devices (thumb drives or USB keys). You

can use standard Cisco CLI commands to read, write, erase, copy, or boot from the flash memory. (Catalyst 2960-S only)

Availability and Redundancy Features

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

support)

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

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

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

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

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

networks. STP has these features:

–

Up to 128 spanning-tree instances supported

Note Up to 64 spanning-tree instances are supported when the switch is running the LAN Lite

image.

–

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

–

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

–

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

1-8

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

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

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Features

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

–

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

–

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

–

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

–

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

–

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

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

redundancy

Note To use Flex Links, the switch must be running the LAN Base image.

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

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

VLAN Features

Note To use Link-state Tracking, the switch must be running the LAN Base image.

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

resources, traffic patterns, and bandwidth

Note Up to 64 VLANs are supported when the switch is running the LAN Lite image.

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

• VLAN Query Protocol (VQP) for dynamic VLAN membership

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

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

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

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

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

flooded traffic to links destined for stations receiving the traffic

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

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Features

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

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

Note To use VLAN Flex Link Load Balancing, the switch must be running the LAN Base image.

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

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

Security Features

Chapter 1 Overview

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

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

VLANs)

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

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

be authenticated using a web browser

Note To use Web Authentication, the switch must be running the LAN Base image.

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

authentication login screen

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

Note To use this feature, the switch must be running the LAN Base image.

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

manager, Network Assistant, and the 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

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

instead of shutting down the entire port.

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

• Protocol storm protection to control the rate of incoming protocol traffic to a switch by dropping

packets that exceed a specified ingress rate.

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

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Features

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

Layer 2 interfaces (port ACLs)

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

interfaces

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

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

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

snooping database and IP source bindings

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

requests and responses to other ports in the same VLAN

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

access to the network. These features are supported:

–

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

Note To use MDA, the switch must be running the LAN Base image.

–

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

–

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

–

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

Note To use this feature, the switch must be running the LAN Base image.

–

Port security for controlling access to 802.1x ports

–

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

–

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

–

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

–

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

Note To use authentication with restricted VLANs, the switch must be running the LAN Base

image.

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–

802.1x accounting to track network usage

–

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

–

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

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Chapter 1 Overview

Note To use 802.1x readiness check, the switch must be running the LAN Base image.

–

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

Note To use voice aware 802.1x authentication, the switch must be running the LAN Base image.

–

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

Note To use MAC authentication bypass, the switch must be running the LAN Base image.

–

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

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

Layer 2 802.1x Validation” section on page 10-60.

Note To use NAC, the switch must be running the LAN Base image.

–

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

–

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

–

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

–

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

Note To use this feature, the switch must be running the LAN Base image.

–

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

–

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

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

IPv4 and IPv6

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

through authentication, authorization, and accounting (AAA) services for both IPv4 and IPv6

• Enhancements to RADIUS, TACACS+, and SSH to function over IPv6.

1-12

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

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

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

• Support for IP source guard on static hosts.

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Features

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

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

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

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

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

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

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

failure and expire web pages for local web authentication.

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

standard port configuration on the authenticator switch port.

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

user authentication to prevent network access from unauthorized VLANs.

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

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

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

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

QoS and CoS Features

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

traffic and configuring egress queues

Note To use auto-QoS, the switch must be running the LAN Base image.

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

individual-switch basis

• Classification

–

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

Note To use DSCP, the switch must be running the LAN Base image.

–

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

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Features

Chapter 1 Overview

Note To use flow-based packet classification, the switch must be running the LAN Base image.

–

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

Note To use trusted boundary, the switch must be running the LAN Base image.

• Policing

Note To use policy maps, the switch must be running the LAN Base image

–

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

–

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

–

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

• Out-of-Profile

–

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

• Ingress queueing and scheduling

–

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

–

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

Note To use WTD, the switch must be running the LAN Base image.

–

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

Note To use ingress queueing, the Catalyst 2960 switch must be running the LAN Base image.

Note Ingress queueing is not supported on Catalyst 2960-S switches.

• Egress queues and scheduling

–

Four egress queues per port

1-14

–

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

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

Layer 3 Features

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

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

Features

–

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.

Note To use egress queueing, the switch must be running the LAN Base image.

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

Note To use Auto-QoS enhancements, the switch must be running the LAN Base image.

router ACLs on SVIs (supported only on switches running the LAN base image).

router (requires the LAN Base image)

Power over Ethernet Features

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

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

• Support for IEEE 802.3at, (PoE+) that increases the available power that can be drawn by powered

devices from 15.4 W per port to 30 W per port (Catalyst 2960-S only)

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

power it is consuming.

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

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

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

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

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

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

Universal Power over Ethernet Features

• Provides the ability to source up to 60 W of power over standard Ethernet cabling infrastructure.

• Sources up to 60 W of power (2X 30W) over both signal and spare pairs of the RJ-45 Ethernet cable

based on IEEE802.3at standards.

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• Automatically detects UPoE-compliant power devices and negotiates power up to 60 W by using

Layer-2 power negotiation protocols, such as CDP or LLDP.

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Features

• Supports the third-party UPoE power device that complies with Cisco Catalyst 3000 switches.

• Sources up to 60 W of power by configuring the 4-pair forced mode interface even if the power

device does not support the Layer-2 power negotiation protocol, such as CDP or LLDP.

• Supports 60 W of power per port, up to 30 ports, on a 48-port SKU or a total power budget of 1800

W with a combination of PoE, PoE+, and UPoE ports.

For more information on UPoE, see Universal Power Over Ethernet, page 12-11.

Note Only Catalyst 2960-C switches support Universal Power over Ethernet.

Monitoring Features

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

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

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

the MAC addresses that the switch has learned or removed

Chapter 1 Overview

• 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-out events.

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

destination device

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

10/100/1000 copper Ethernet ports

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

module

• Generic online diagnostics to test hardware functionality of the supervisor engine, modules, and

switch while the switch is connected to a live network(Catalyst 2960-S only).

• On-board failure logging (OBFL) to collect information about the switch and the power supplies

connected to it (Catalyst 2960-S only)

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

device for IP SLAs active traffic monitoring

1-16

Note To use IP SLAs, the switch must be running the LAN Base image.

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Default Settings After Initial Switch Configuration

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

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

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

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

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

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

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

IP Address and Default Gateway.”

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

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

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

• Switch stack is enabled (not configurable). For more information, see Chapter 7, “Managing Switch

Stacks.”

• Switch cluster is disabled. For more information about switch clusters, see Chapter 6, “Clustering

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

• No passwords are defined. For more information, see Chapter 5, “Administering the Switch.”

• System name and prompt is Switch. For more information, see Chapter 5, “Administering the

Switch.”

• NTP is enabled. For more information, see Chapter 5, “Administering the Switch.”

• DNS is enabled. For more information, see Chapter 5, “Administering the Switch.”

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

Authentication.”

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

Authentication.”

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

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

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

Port-Based Authentication.”

• Port parameters

–

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

–

Auto-MDIX is enabled. For more information, see

–

Flow control is off. For more information, see

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PoE is autonegotiate. For more information, see

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Default Settings After Initial Switch Configuration

• VLANs

–

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

–

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

“Configuring VLANs.”

–

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

–

VTP mode is server. For more information, see Chapter 14, “Configuring VTP.”

–

VTP version is Version 1. For more information, see Chapter 14, “Configuring VTP.”

–

Voice VLAN is disabled. For more information, see Chapter 15, “Configuring Voice VLAN.”

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

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

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

Optional Spanning-Tree Features.”

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

the MAC Address-Table Move Update Feature.”

Chapter 1 Overview

Note To use Flex Links, the switch must be running the LAN Base image.

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

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

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

Source Guard Features.”

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

“Configuring DHCP and IP Source Guard Features.”

• Dynamic ARP inspection is disabled on all VLANs. For more information, see Chapter 22,

“Configuring Dynamic ARP Inspection.”

• IGMP snooping is enabled. No IGMP filters are applied. For more information, see Chapter 21,

“Configuring IGMP Snooping and MVR.”

• IGMP throttling setting is deny. For more information, see Chapter 21, “Configuring IGMP

Snooping and MVR.”

• The IGMP snooping querier feature is disabled. For more information, see Chapter 21, “Configuring

IGMP Snooping and MVR.”

• MVR is disabled. For more information, see Chapter 21, “Configuring IGMP Snooping and MVR.”

Note To use MVR, the switch must be running the LAN Base image.

• Port-based traffic

1-18

–

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

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

–

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

Traffic Control.”

–

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

“Configuring Port-Based Traffic Control.”

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Network Configuration Examples

–

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

Traffic Control.”

• CDP is enabled. For more information, see Chapter 25, “Configuring CDP.”

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

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

RSPAN.”

Note To use RSPAN, the switch must be running the LAN Base image.

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

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

“Configuring System Message Logging.”

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

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

with ACLs.”

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

• No EtherChannels are configured. For more information, see Chapter 38, “Configuring

EtherChannels and Link-State Tracking.”

Network Configuration Examples

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

• “Design Concepts for Using the Switch” section on page 1-19

• “Small to Medium-Sized Network Using Catalyst 2960, 2960-S and 2960-C Switches” section on

page 1-24

• “Long-Distance, High-Bandwidth Transport Configuration” section on page 1-25

Design Concepts for Using the Switch

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

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Network Configuration Examples

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

network to increase the bandwidth available to your network users.

Table 1-1 Increasing Network Performance

Network Demands Suggested Design Methods

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

• Increased power of new PCs,

workstations, and servers

• High bandwidth demand from

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

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

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

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

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

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

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

routers.

Chapter 1 Overview

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

Table 1-2 Providing Network Services

Network Demands Suggested Design Methods

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

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

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

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

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

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

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

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

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

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

image.

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

stack.

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

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

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

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

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

1-20

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Table 1-2 Providing Network Services (continued)

Network Demands Suggested Design Methods

An evolving demand for IP telephony

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

• Use QoS to prioritize applications such as IP telephony during congestion and to

help control both delay and jitter within the network.

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

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

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

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

Note To use LRE, the switch must be running the LAN Base image.

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

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

Network Configuration Examples

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

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

closet is to have a switch stack of up to four Catalyst 2960-S switches. To preserve switch connectivity if one switch in the stack fails, connect the switches as recommended in the hardware installation guide, and enable either cross-stack Etherchannel or cross-stack UplinkFast.

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

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

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Access-layer Catalyst switches

Catalyst 3750 switches

Figure 1-1 Cost-Effective Wiring Closet

Gigabit

server

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

high-speed access to network resources, you can use the Catalyst 2960 switch in the access layer to provide Gigabit Ethernet to the desktop. To prevent congestion, use QoS DSCP marking priorities on these switches. For high-speed IP forwarding at the distribution layer, connect the switches in the access layer to a Gigabit multilayer switch with routing capability, such as a Catalyst 3750 switch, or to a router.

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

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

Chapter 1 Overview

Catalyst Gigabit Ethernet multilayer switch

Catalyst 2975

switch stack

250870

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

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Network Configuration Examples

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

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

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

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

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

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

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Campus

core

Catalyst 6500 switches

Catalyst 3750 StackWise switch stacks

Access-layer Catalyst switches

Server racks

Figure 1-3 Server Aggregation

Chapter 1 Overview

Small to Medium-Sized Network Using Catalyst 2960, 2960-S and 2960-C Switches

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

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

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

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

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

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

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

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

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Gigabit servers

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Cisco 2600 or

3700 routers

Internet

Cisco IP

phones

Workstations

running

Cisco SoftPhone

software

Aironet wireless

access points

IP IP

Network Configuration Examples

Figure 1-4 Collapsed Backbone Configuration

Long-Distance, High-Bandwidth Transport Configuration

Note To use CWDM SFPs, the switch must be running the LAN Base image.

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

Catalyst 2960, 2960-S or 2960-C switches have coarse wavelength-division multiplexing (CWDM) fiber-optic SFP modules installed. Depending on the CWDM SFP module, data is sent at wavelengths from 1470 to 1610 nm. The higher the wavelength, the farther the transmission can travel. A common wavelength used for long-distance transmissions is 1550 nm.

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

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

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Chapter 1 Overview

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

Where to Go Next

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

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

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

To locate and download MIBs for a specific Cisco product and release, use the Cisco MIB Locator:

http://cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.

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Using the Command-Line Interface

This chapter describes the Cisco IOS command-line interface (CLI) and how to use it to configure your 2960, 2960-SC or 2960-S switch.Unless otherwise noted, the term switch refers to a standalone switch and to a switch stack.

• Understanding Command Modes, page 2-1

• Understanding the Help System, page 2-3

• Understanding Abbreviated Commands, page 2-3

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

• Understanding CLI Error Messages, page 2-4

• Using Configuration Logging, page 2-4

• 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-time commands, such as show commands, which show the current configuration status, and clear commands, which clear counters or interfaces. The user EXEC commands are not saved when the switch reboots.

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

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

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Understanding Command Modes

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

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

Table 2-1 Command Mode Summary

Mode Access Method Prompt Exit Method About This Mode

User EXEC Begin a session

with your switch.

Privileged EXEC While in user

EXEC mode, enter the enable command.

Global configuration While in privileged

EXEC mode, enter the configure command.

VLAN configuration While in global

configuration mode, enter the vlan vlan-id command.

Interface configuration

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

Switch>

Switch#

Switch(config)#

Switch(config-vlan)#

Switch(config-if)#

Enter logout or quit.

Enter disable to exit.

To exit to privileged EXEC mode, enter

exit or end, or press Ctrl-Z.

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

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

To exit to global configuration mode, enter exit.

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

Use this mode to

• Change terminal settings.

• Perform basic tests.

• Display system

information.

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

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

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

Use this mode to configure parameters for the Ethernet ports.

For information about defining interfaces, see the “Using

Interface Configuration Mode” section on page 12-16.

Line configuration While in global

configuration mode, specify a line with the

line vty or line console command.

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Switch(config-line)#

To exit to global configuration mode, enter exit.

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

To configure multiple interfaces with the same parameters, see the “Configuring a Range of

Interfaces” section on page 12-18.

Use this mode to configure parameters for the terminal line.

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Understanding the Help System

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

Understanding the Help System

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

Table 2-2 Help Summary

Command Purpose

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

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

For example:

Switch# di? dir disable disconnect

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

For example:

Switch# sh conf<tab> Switch# show configuration

? 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

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Understanding no and default Forms of Commands

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

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

Understanding CLI Error Messages

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

switch.

Table 2-3 Common CLI Error Messages

Error Message Meaning How to Get Help

% Ambiguous command: "show con"

% Incomplete command.

% Invalid input detected at ‘^’ marker.

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

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

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

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

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

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

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

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

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

Using Configuration Logging

You can log and view changes to the switch configuration. You can use the Configuration Change Logging and Notification feature to track changes on a per-session and per-user basis. The logger tracks each configuration command that is applied, the user who entered the command, the time that the

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command was entered, and the parser return code for the command. This feature includes a mechanism for asynchronous notification to registered applications whenever the configuration changes. You can choose to have the notifications sent to the syslog.

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

http://www.cisco.com/en/US/docs/ios/fundamentals/configuration/guide/cf_config-logger_ps6350_TS D_Products_Configuration_Guide_Chapter.html

Note Only CLI or HTTP changes are logged.

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)

Using Command History

• 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 [size number-of-lines]

The range is from 0 to 256.

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

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

The range is from 0 to 256.

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Using Editing Features

Recalling Commands

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

Table 2-4 Recalling Commands

Action

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

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

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

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

Result

Repeat the key sequence to recall successively older commands.

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

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

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 2-6 (optional)

• Editing Commands through Keystrokes, page 2-7 (optional)

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

Enabling and Disabling Editing Features

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

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

Switch (config-line)# no editing

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

Switch# terminal editing

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

Switch(config-line)# editing

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

Using Editing Features

Capability Keystroke

Move around the command line to make changes or corrections.

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

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

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

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

Press Esc B. Move the cursor back one word.

Press Esc F. Move the cursor forward one word.

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

Recall commands from the buffer and

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

Press Esc Y. Recall the next buffer entry.

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

Press the Delete or

Backspace key.

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

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

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

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

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

Capitalize or lowercase words or

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

Purpose

Move the cursor back one character.

Move the cursor forward one character.

character located at the cursor.

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

Erase the character to the left of the cursor.

command line.

the command line.

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Table 2-5 Editing Commands through Keystrokes (continued)

Chapter 2 Using the Command-Line Interface

Capability Keystroke

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

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

Designate a particular keystroke as

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

Scroll down a line or screen on

Press the Return key. Scroll down one line. displays that are longer than the terminal screen can display.

Note The More prompt is used for

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

Press the Space bar. Scroll down one screen.

Redisplay the current command line

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

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

Purpose

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 press Ctrl-A to immediately move to the beginning of the line.

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

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

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

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

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

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Searching and Filtering Output of show and more Commands

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

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

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

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

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

Switch# show interfaces | include protocol Vlan1 is up, line protocol is up Vlan10 is up, line protocol is down

Accessing the CLI

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

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

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

Note We recommend using one CLI session when managing the switch stack.

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

Interface Configuration Mode” section on page 12-16.

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

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

Switch. Only the show and debug commands are available in

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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 getting started guide that shipped with your switch. Then, to understand the boot process and the options available for assigning IP information, see Chapter 3, “Assigning the

Switch IP Address and Default Gateway.”

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

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

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

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

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

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

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

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

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

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

Shell” section on page 9-42. 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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Assigning the Switch IP Address and Default Gateway

Note This chapter describes how to create the initial switch configuration (for example, assigning the IP

address and default gateway information) for the Catalyst switch by using a variety of automatic and manual methods. It also describes how to modify the switch startup configuration. For complete syntax and usage information for the commands used in this chapter, see the command reference for this release and the Cisco IOS IP Command Reference, Volume 1 of 3: Addressing and Services from Cisco.com page.

• Understanding the Boot Process, page 3-1

• Assigning Switch Information, page 3-2

• Checking and Saving the Running Configuration, page 3-15

• Modifying the Startup Configuration, page 3-17

• Scheduling a Reload of the Software Image, page 3-22

Understanding the Boot Process

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

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

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

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

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

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

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

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

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

page 39-2 and the “Recovering from a Lost or Forgotten Password” section on page 39-3.

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

section on page 9-5.

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

• Baud rate default is 9600.

• Data bits default is 8.

Chapter 3 Assigning the Switch IP Address and Default Gateway

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.

• Default Switch Information, page 3-3

3-2

• Understanding DHCP-Based Autoconfiguration, page 3-3

• Manually Assigning IP Information, page 3-14

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Default Switch Information

Table 3- 1 shows the default switch information.

Table 3-1 Default Switch Information

Feature Default Setting

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

Default gateway No default gateway is defined.

Enable secret password No password is defined.

Hostname The factory-assigned default hostname is Switch.

Telnet password No password is defined.

Cluster command switch functionality Disabled.

Cluster name No cluster name is defined.

Understanding DHCP-Based Autoconfiguration

Assigning Switch Information

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

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

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

The DHCP server for your switch can be on the same LAN or on a different LAN than the switch. If the DHCP server is running on a different LAN, you should configure a DHCP relay device between your switch and the DHCP server. A relay device forwards broadcast traffic between two directly connected LANs. A router does not forward broadcast packets, but it forwards packets based on the destination IP address in the received packet.

DHCP-based autoconfiguration replaces the BOOTP client functionality on your switch.

DHCP Client Request Process

When you boot up your switch, the DHCP client is invoked and requests configuration information from a DHCP server when the configuration file is not present on the switch. If the configuration file is present and the configuration includes the ip address dhcp interface configuration command on specific routed interfaces, the DHCP client is invoked and requests the IP address information for those interfaces.

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Switch A

DHCPACK (unicast)

DHCPREQUEST (broadcast)

DHCPOFFER (unicast)

DHCPDISCOVER (broadcast)

DHCP server

51807

Figure 3-1 shows the sequence of messages that are exchanged between the DHCP client and the DHCP

server.

Figure 3-1 DHCP Client and Server Message Exchange

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 3-7.

Chapter 3 Assigning the Switch IP Address and Default Gateway

If the configuration parameters sent to the client in the DHCPOFFER unicast message are invalid (a configuration error exists), the client returns a DHCPDECLINE broadcast message to the DHCP server.

The DHCP server sends the client a DHCPNAK denial broadcast message, which means that the offered configuration parameters have not been assigned, that an error has occurred during the negotiation of the parameters, or that the client has been slow in responding to the DHCPOFFER message. (The DHCP server assigned the parameters to another client.)

A DHCP client might receive offers from multiple DHCP or BOOTP servers and can accept any of the offers; however, the client usually accepts the first offer it receives. The offer from the DHCP server is not a guarantee that the IP address is allocated to the switch. However, the server usually reserves the address until the client has had a chance to formally request the address. If the switch accepts replies from a BOOTP server and configures itself, the switch broadcasts, instead of unicasts, TFTP requests to obtain the switch configuration file.

The DHCP hostname option allows a group of switches to obtain hostnames and a standard configuration from the central management DHCP server. A client (switch) includes in its DCHPDISCOVER message an option 12 field used to request a hostname and other configuration parameters from the DHCP server. The configuration files on all clients are identical except for their DHCP-obtained hostnames.

If a client has a default hostname (the hostname name global configuration command is not configured or the no hostname global configuration command is entered to remove the hostname), the DHCP hostname option is not included in the packet when you enter the ip address dhcp interface configuration command. In this case, if the client receives the DCHP hostname option from the DHCP interaction while acquiring an IP address for an interface, the client accepts the DHCP hostname option and sets the flag to show that the system now has a hostname configured.

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Assigning Switch Information

Understanding DHCP-based Autoconfiguration and Image Update

You can use the DHCP image upgrade features to configure a DHCP server to download both a new image and a new configuration file to one or more switches in a network. This helps ensure that each new switch added to a network receives the same image and configuration.

There are two types of DHCP image upgrades: DHCP autoconfiguration and DHCP auto-image update.

DHCP Autoconfiguration

DHCP autoconfiguration downloads a configuration file to one or more switches in your network from a DHCP server. The downloaded configuration file becomes the running configuration of the switch. It does not over write the bootup configuration saved in the flash, until you reload the switch.

DHCP Auto-Image Update

You can use DHCP auto-image upgrade with DHCP autoconfiguration to download both a configuration and a new image to one or more switches in your network. The switch (or switches) downloading the new configuration and the new image can be blank (or only have a default factory configuration loaded).

If the new configuration is downloaded to a switch that already has a configuration, the downloaded configuration is appended to the configuration file stored on the switch. (Any existing configuration is not overwritten by the downloaded one.)

Note To enable a DHCP auto-image update on the switch, the TFTP server where the image and configuration

files are located must be configured with the correct option 67 (the configuration filename), option 66 (the DHCP server hostname) option 150 (the TFTP server address), and option 125 (description of the file) settings.

For procedures to configure the switch as a DHCP server, see the “Configuring DHCP-Based

Autoconfiguration” section on page 3-6 and the “Configuring DHCP” section of the “IP addressing and

Services” section of the Cisco IOS IP Configuration Guide, Release 12.2.

After you install the switch in your network, the auto-image update feature starts. The downloaded configuration file is saved in the running configuration of the switch, and the new image is downloaded and installed on the switch. When you reboot the switch, the configuration is stored in the saved configuration on the switch.

Limitations and Restrictions

• The DHCP-based autoconfiguration with a saved configuration process stops if there is not at least

one Layer 3 interface in an up state without an assigned IP address in the network.

• Unless you configure a timeout, the DHCP-based autoconfiguration with a saved configuration

feature tries indefinitely to download an IP address.

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• The auto-install process stops if a configuration file cannot be downloaded or it the configuration

file is corrupted.

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Note The configuration file that is downloaded from TFTP is merged with the existing configuration in the

running configuration but is not saved in the NVRAM unless you enter the write memory or copy running-configuration startup-configuration privileged EXEC command. Note that if the

downloaded configuration is saved to the startup configuration, the feature is not triggered during subsequent system restarts.

Configuring DHCP-Based Autoconfiguration

• DHCP Server Configuration Guidelines, page 3-6

• Configuring the TFTP Server, page 3-7

• Configuring the DNS, page 3-7

• Configuring the Relay Device, page 3-7

• Obtaining Configuration Files, page 3-8

• Example Configuration, page 3-9

Chapter 3 Assigning the Switch IP Address and Default Gateway

DHCP Server Configuration Guidelines

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)

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

• DNS server IP address (optional)

If you want the switch to receive the configuration file from a TFTP server, you must configure the DHCP server with these lease options:

• TFTP server name (required)

• Boot filename (the name of the configuration file that the client needs) (recommended)

• Hostname (optional)

Depending on the settings of the DHCP server, the switch can receive IP address information, the configuration file, or both.

If you do not configure the DHCP server with the lease options described previously, it replies to client requests with only those parameters that are configured. If the IP address and the subnet mask are not in the reply, the switch is not configured. If the router IP address or the TFTP server name are not found, the switch might send broadcast, instead of unicast, TFTP requests. Unavailability of other lease options does not affect autoconfiguration.

The switch can act as a DHCP server. By default, the Cisco IOS DHCP server and relay agent features are enabled on your switch but are not configured. These features are not operational. If your DHCP server is a Cisco device, for additional information about configuring DHCP, see the “Configuring DHCP” section of the “IP Addressing and Services” section of the Cisco IOS IP Configuration Guide on Cisco.com page.

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Configuring the TFTP Server

Based on the DHCP server configuration, the switch attempts to download one or more configuration files from the TFTP server. If you configured the DHCP server to respond to the switch with all the options required for IP connectivity to the TFTP server, and if you configured the DHCP server with a TFTP server name, address, and configuration filename, the switch attempts to download the specified configuration file from the specified TFTP server.

If you did not specify the configuration filename, the TFTP server, or if the configuration file could not be downloaded, the switch attempts to download a configuration file by using various combinations of filenames and TFTP server addresses. The files include the specified configuration filename (if any) and these files: network-config, cisconet.cfg, hostname.config, or hostname.cfg, where hostname is the switch’s current hostname. The TFTP server addresses used include the specified TFTP server address (if any) and the broadcast address (255.255.255.255).

For the switch to successfully download a configuration file, the TFTP server must contain one or more configuration files in its base directory. The files can include these files:

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

• The network-confg or the cisconet.cfg file (known as the default configuration files).

• The router-confg or the ciscortr.cfg file (These files contain commands common to all switches.

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-lease database, you must also configure the TFTP server name-to-IP-address mapping in the DNS-server database.

Assigning Switch Information

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 3-7. The preferred solution is to configure the DHCP server with all the required information.

Configuring the DNS

The DHCP server uses the DNS server to resolve the TFTP server name to an IP address. You must configure the TFTP server name-to-IP address map on the DNS server. The TFTP server contains the configuration files for the switch.

You can configure the IP addresses of the DNS servers in the lease database of the DHCP server from where the DHCP replies will retrieve them. You can enter up to two DNS server IP addresses in the lease database.

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.

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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.

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Switch

(DHCP client)

Cisco router

(Relay)

49068

DHCP server TFTP server DNS server

20.0.0.2 20.0.0.3

20.0.0.1

10.0.0.2

10.0.0.1

20.0.0.4

For example, in Figure 3-2, configure the router interfaces as follows:

On interface 10.0.0.2:

router(config-if)# ip helper-address 20.0.0.2 router(config-if)# ip helper-address 20.0.0.3 router(config-if)# ip helper-address 20.0.0.4

On interface 20.0.0.1

router(config-if)# ip helper-address 10.0.0.1

Figure 3-2 Relay Device Used in Autoconfiguration

Chapter 3 Assigning the Switch IP Address and Default Gateway

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-file read method).

The switch receives its IP address, subnet mask, TFTP server address, and the configuration filename from the DHCP server. The switch sends a unicast message to the TFTP server to retrieve the named configuration file from the base directory of the server and upon receipt, it completes its boot-up process.

• 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-file read method).

The switch receives its IP address, subnet mask, and the configuration filename from the DHCP server. The switch sends a broadcast message to a TFTP server to retrieve the named configuration file from the base directory of the server, and upon receipt, it completes its boot-up process.

• Only the IP address is reserved for the switch and provided in the DHCP reply. The configuration

filename is not provided (two-file read method).

The switch receives its IP address, subnet mask, and the TFTP server address from the DHCP server. The switch sends a unicast message to the TFTP server to retrieve the network-confg or cisconet.cfg default configuration file. (If the network-confg file cannot be read, the switch reads the cisconet.cfg file.)

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Switch 1

00e0.9f1e.2001

Cisco router

111394

Switch 2

00e0.9f1e.2002

Switch 3

00e0.9f1e.2003

DHCP server DNS server TFTP server

(tftpserver)

10.0.0.1

10.0.0.10

10.0.0.2 10.0.0.3

Switch 4

00e0.9f1e.2004

The default configuration file contains the hostnames-to-IP-address mapping for the switch. The switch fills its host table with the information in the file and obtains its hostname. If the hostname is not found in the file, the switch uses the hostname in the DHCP reply. If the hostname is not specified in the DHCP reply, the switch uses the default Switch as its hostname.

After obtaining its hostname from the default configuration file or the DHCP reply, the switch reads the configuration file that has the same name as its hostname (hostname-confg or hostname.cfg, depending on whether network-confg or cisconet.cfg was read earlier) from the TFTP server. If the cisconet.cfg file is read, the filename of the host is truncated to eight characters.

If the switch cannot read the network-confg, cisconet.cfg, or the hostname file, it reads the router-confg file. If the switch cannot read the router-confg file, it reads the ciscortr.cfg file.

Note The switch broadcasts TFTP server requests if the TFTP server is not obtained from the DHCP replies,

if all attempts to read the configuration file through unicast transmissions fail, or if the TFTP server name cannot be resolved to an IP address.

Example Configuration

Assigning Switch Information

Figure 3-3 shows a sample network for retrieving IP information by using DHCP-based

autoconfiguration.

Figure 3-3 DHCP-Based Autoconfiguration Network Example

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

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Table 3-2 DHCP Server Configuration (continued)

Switch A Switch B Switch C Switch D

TFTP server name tftpserver or

10.0.0.3

Boot filename (configuration file)

switcha-confg switchb-confg switchc-confg switchd-confg

(optional)

Hostname (optional) switcha switchb switchc switchd

DNS Server Configuration

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

TFTP Server Configuration (on UNIX)

The TFTP server base directory is set to /tftpserver/work/. This directory contains the network-confg file used in the two-file read method. This file contains the hostname to be assigned to the switch based on its IP address. The base directory also contains a configuration file for each switch (switcha-confg, switchb-confg, and so forth) as shown in this display:

prompt> cd /tftpserver/work/ prompt> ls network-confg switcha-confg switchb-confg switchc-confg switchd-confg prompt> cat network-confg ip host switcha 10.0.0.21 ip host switchb 10.0.0.22 ip host switchc 10.0.0.23 ip host switchd 10.0.0.24

tftpserver or

10.0.0.3

tftpserver or

10.0.0.3

tftpserver or

10.0.0.3

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-confg

• It adds the contents of the network-confg file to its host table.

• It reads its host table by indexing its IP address 10.0.0.21 to its hostname (switcha).

• It reads the configuration file that corresponds to its hostname; for example, it reads switch1-confg

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

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file from the base directory of the TFTP server.

from the TFTP server.

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Assigning Switch Information

Configuring the DHCP Auto Configuration and Image Update Features

Using DHCP to download a new image and a new configuration to a switch requires that you configure at least two switches: One switch acts as a DHCP and TFTP server. The client switch is configured to download either a new configuration file or a new configuration file and a new image file.

Configuring DHCP Autoconfiguration (Only Configuration File)

Beginning in privileged EXEC mode, follow these steps to configure DHCP autoconfiguration of the TFTP and DHCP settings on a new switch to download a new configuration file.

Command Purpose

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Step 7

Step 8

Step 9

Step 10

Step 11

Step 12

Step 13

configure terminal Enter global configuration mode.

ip dhcp poolname Create a name for the DHCP Server address pool, and enter DHCP

pool configuration mode.

bootfile filename Specify the name of the configuration file that is used as a boot image.

network network-number mask

prefix-length

Specify the subnet network number and mask of the DHCP address pool.

Note The prefix length specifies the number of bits that comprise

the address prefix. The prefix is an alternative way of specifying the network mask of the client. The prefix length must be preceded by a forward slash (/).

default-router address Specify the IP address of the default router for a DHCP client.

option 150 address Specify the IP address of the TFTP server.

exit Return to global configuration mode.

tftp-server flash:filename.text Specify the configuration file on the TFTP server.

interface interface-id Specify the address of the client that will receive the configuration

file.

no switchport Put the interface into Layer 3 mode.

ip address address mask Specify the IP address and mask for the interface.

end Return to privileged EXEC mode.

copy running-config startup-config (Optional) Save your entries in the configuration file.

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This example shows how to configure a switch as a DHCP server so that it will download a configuration file:

Switch# configure terminal Switch(config)# ip dhcp pool pool1 Switch(dhcp-config)# network 10.10.10.0 255.255.255.0 Switch(dhcp-config)# bootfile config-boot.text Switch(dhcp-config)# default-router 10.10.10.1 Switch(dhcp-config)# option 150 10.10.10.1 Switch(dhcp-config)# exit Switch(config)# tftp-server flash:config-boot.text Switch(config-if)# no switchport Switch(config-if)# ip address 10.10.10.1 255.255.255.0 Switch(config-if)# end

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Configuring DHCP Auto-Image Update (Configuration File and Image)

Beginning in privileged EXEC mode, follow these steps to configure DHCP autoconfiguration to configure TFTP and DHCP settings on a new switch to download a new image and a new configuration file.

Note Before following the steps in this table, you must create a text file (for example, autoinstall_dhcp) that

will be uploaded to the switch. In the text file, put the name of the image that you want to download. This image must be a tar and not a bin file.

Command Purpose

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Step 7

Step 8

Step 9

Step 10

Step 11

Step 12

Step 13

Step 14

Step 15

Step 16

Step 17

Step 18

configure terminal Enter global configuration mode.

ip dhcp pool name Create a name for the DHCP server address pool and enter DHCP pool

configuration mode.

bootfile filename Specify the name of the file that is used as a boot image.

network network-number mask

prefix-length

Specify the subnet network number and mask of the DHCP address pool.

Note The prefix length specifies the number of bits that comprise the

address prefix. The prefix is an alternative way of specifying the network mask of the client. The prefix length must be preceded by a forward slash (/).

default-router address Specify the IP address of the default router for a DHCP client.

option 150 address Specify the IP address of the TFTP server.

option 125 hex Specify the path to the text file that describes the path to the image file.

copy tftp flash filename.txt Upload the text file to the switch.

copy tftp flash imagename.tar Upload the tar file for the new image to the switch.

exit Return to global configuration mode.

tftp-server flash:config.text Specify the Cisco IOS configuration file on the TFTP server.

tftp-server flash:imagename.tar Specify the image name on the TFTP server.

tftp-server flash:filename.txt Specify the text file that contains the name of the image file to download

interface interface-id Specify the address of the client that will receive the configuration file.

no switchport Put the interface into Layer 3 mode.

ip address address mask Specify the IP address and mask for the interface.

end Return to privileged EXEC mode.

copy running-config startup-config (Optional) Save your entries in the configuration file.

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This example shows how to configure a switch as a DHCP server so it downloads a configuration file:

Switch# config terminal Switch(config)# ip dhcp pool pool1 Switch(dhcp-config)# network 10.10.10.0 255.255.255.0 Switch(dhcp-config)# bootfile config-boot.text Switch(dhcp-config)# default-router 10.10.10.1 Switch(dhcp-config)# option 150 10.10.10.1 Switch(dhcp-config)# option 125 hex

0000.0009.0a05.08661.7574.6f69.6e73.7461.6c6c.5f64.686370

Switch(dhcp-config)# exit Switch(config)# tftp-server flash:config-boot.text Switch(config)# tftp-server flash:boot-config.text Switch(config)# tftp-server flash: autoinstall_dhcp Switch(config-if)# no switchport Switch(config-if)# ip address 10.10.10.1 255.255.255.0 Switch(config-if)# end

Configuring the Client

Beginning in privileged EXEC mode, follow these steps to configure a switch to download a configuration file and new image from a DHCP server:

Assigning Switch Information

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Command Purpose

configure terminal Enter global configuration mode.

boot host dhcp Enable autoconfiguration with a saved configuration.

boot host retry timeout timeout-value (Optional) Set the amount of time the system tries to

download a configuration file.

Note If you do not set a timeout the system will

indefinitely try to obtain an IP address from the DHCP server.

banner config-save ^C warning-message ^C (Optional) Create warning messages to be displayed

when you try to save the configuration file to NVRAM.

end Return to privileged EXEC mode.

show boot Verify the configuration.

This example uses a Layer 3 SVI interface on VLAN 99 to enable DHCP-based autoconfiguration with a saved configuration:

Switch# configure terminal Switch(conf)# boot host dhcp Switch(conf)# boot host retry timeout 300 Switch(conf)# banner config-save ^C Caution - Saving Configuration File to NVRAM May Cause

You to No longer Automatically Download Configuration Files at Reboot^C

Switch(config)# vlan 99 Switch(config-vlan)# interface vlan 99 Switch(config-if)# no shutdown Switch(config-if)# end Switch# show boot BOOT path-list: Config file: flash:/config.text Private Config file: flash:/private-config.text Enable Break: no Manual Boot: no HELPER path-list:

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NVRAM/Config file buffer size: 32768 Timeout for Config Download: 300 seconds Config Download via DHCP: enabled (next boot: enabled) Switch#

Note You should only configure and enable the Layer 3 interface. Do not assign an IP address or DHCP-based

autoconfiguration with a saved configuration.

Manually Assigning IP Information

Beginning in privileged EXEC mode, follow these steps to manually assign IP information to multiple switched virtual interfaces (SVIs):

Command Purpose

Step 1

Step 2

Step 3

Step 4

Step 5

configure terminal Enter global configuration mode.

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

information is assigned. The VLAN range is 1 to 4094.

ip address ip-address subnet-mask Enter the IP address and subnet mask.

exit Return to global configuration mode.

ip default-gateway ip-address Enter the IP address of the next-hop router interface that is directly

connected to the switch where a default gateway is being configured. The default gateway receives IP packets with unresolved destination IP addresses from the switch.

Once the default gateway is configured, the switch has connectivity to the remote networks with which a host needs to communicate.

Chapter 3 Assigning the Switch IP Address and Default Gateway

Step 6

Step 7

Step 8

Step 9

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Note When your switch is configured to route with IP, it does not need

to have a default gateway set.

end Return to privileged EXEC mode.

show interfaces vlan vlan-id Verify the configured IP address.

show ip redirects Verify the configured default gateway.

copy running-config startup-config (Optional) Save your entries in the configuration file.

To remove the switch IP address, use the no ip address interface configuration command. If you are removing the address through a Telnet session, your connection to the switch will be lost. To remove the default gateway address, use the no ip default-gateway global configuration command.

For information on setting the switch system name, protecting access to privileged EXEC commands, and setting time and calendar services, see Chapter 5, “Administering the Switch.”

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Checking and Saving the Running Configuration

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

Switch# show running-config Building configuration...

Current configuration: 1363 bytes ! version 12.2 no service pad service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname ! enable secret 5 $1$ej9.$DMUvAUnZOAmvmgqBEzIxE0 ! . <output truncated> . ip address 172.20.137.50 255.255.255.0 ! mvr type source

...! interface VLAN1 ip address 172.20.137.50 255.255.255.0 no ip directed-broadcast ! ip default-gateway 172.20.137.1 ! ! snmp-server community private RW snmp-server community public RO snmp-server community private@es0 RW snmp-server community public@es0 RO snmp-server chassis-id 0x12 ! end

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

Switch# copy running-config startup-config Destination filename [startup-config]? Building configuration...

This command saves the configuration settings that you made. If you fail to do this, your configuration will be lost the next time you reload the system. To display information stored in the NVRAM section of flash memory, use the show startup-config or more startup-config privileged EXEC command.

For more information about alternative locations from which to copy the configuration file, see

Appendix A, “Working with the Cisco IOS File System, Configuration Files, and Software Images.”

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Configuring the NVRAM Buffer Size

The default NVRAM buffer size is 512 KB. In some cases, the configuration file might be too large to save to NVRAM. Typically, this occurs when you have many switches in a switch stack. You can configure the size of the NVRAM buffer to support larger configuration files. The new NVRAM buffer size is synced to all current and new member switches.

Note After you configure the NVRAM buffer size, reload the switch or switch stack.

When you add a switch to a stack and the NVRAM size differs, the new switch syncs with the stack and reloads automatically.

Beginning in privileged EXEC mode, follow these steps to configure the NVRAM buffer size:

Command Purpose

Step 1

Step 2

Step 3

Step 4

configure terminal Enter global configuration mode.

boot buffersize size Configure the NVRAM buffersize in KB. The valid range

end Return to privileged EXEC mode.

show boot Verify the configuration.

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for size is from 4096 to 1048576.

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