Catalyst 2950 Desktop Switch Software Configuration Guide, 12.1(9)EA1
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The Catalyst 2950 Desktop Switch Software Configuration Guide is for the network manager responsible for configuring the Catalyst 2950 switches, hereafter referred to as the switches. Before using this guide, you should be familiar with the concepts and terminology of Ethernet and local area networking.


This guide provides information about configuring and troubleshooting a switch or switch clusters. It includes descriptions of the management interface options and the features supported by the switch software. The Catalyst 2950 switch is supported by either the standard software image (SI) or the enhanced software image (EI). The enhanced software image provides a richer set of features, including access control lists (ACLs), enhanced quality of service (QoS) features, the Secure Shell Protocol, extended-range VLANs, IEEE 802.1W Rapid Spanning Tree Protocol (STP), and the IEEE 802.1S Multiple STP.

The enhanced software image supports these switches:

Catalyst 2950C-24

Catalyst 2950G-12-EI

Catalyst 2950G-24-EI

Catalyst 2950G-24-EI-DC

Catalyst 2950G-48-EI

Catalyst 2950T-24

The standard software image supports these switches:

Catalyst 2950-12

Catalyst 2950-24

Use this guide with other documents for information about these topics:

Requirements—This guide assumes that you have met the hardware and software requirements and cluster compatibility requirements described in the release notes.

Start-up information—This guide assumes that you have assigned switch IP information and passwords by using the setup program described in the release notes.

Cluster Management Suite (CMS) information—This guide provides an overview of the CMS web-based, switch management interface. For information about CMS requirements and the procedures for browser and plug-in configuration and accessing CMS, refer to the release notes. For CMS field-level window descriptions and procedures, refer to the CMS online help.

Cluster configuration—This guide provides information about planning for, creating, and maintaining switch clusters. Because configuring switch clusters is most easily performed through CMS, this guide does not provide the command-line interface (CLI) procedures. For the cluster commands, refer to the Catalyst 2950 Desktop Switch Command Reference.

CLI command information—This guide provides an overview for using the CLI. For complete syntax and usage information about the commands that have been specifically created or changed for the Catalyst 2950 switches, refer to the Catalyst 2950 Desktop Switch Command Reference.

This guide does not describe system messages you might encounter or how to install your switch. For more information, refer to the Catalyst 2950 Desktop Switch System Message Guide for this release and to the Catalyst 2950 Desktop Switch Hardware Installation Guide.

Note This guide does not repeat the concepts and CLI procedures provided in the standard Cisco IOS
Release 12.1 documentation. For information about the standard IOS Release 12.1 commands, refer to the IOS documentation set available from the home page at Service and Support > Technical Documents. On the Cisco Product Documentation home page, select Release 12.1 from the Cisco IOS Software drop-down list.


This guide is organized into these chapters:

"Overview," lists the software features of this release and provides examples of how the switch can be deployed in a network.

"Using the Command-Line Interface," describes how to access the command modes, use the command-line interface (CLI), and describes CLI messages that you might receive. It also describes how to get help, abbreviate commands, use no and default forms of commands, use command history and editing features, and how to search and filter the output of show and more commands.

"Getting Started with CMS," describes the Cluster Management Suite (CMS) web-based, switch management interface. For information on configuring your web browser and accessing CMS, refer to the release notes. For field-level descriptions of all CMS windows and procedures for using the CMS windows, refer to the online help.

"Assigning the Switch IP Address and Default Gateway," describes how to create the initial switch configuration (for example, assign the switch IP address and default gateway information) by using a variety of automatic and manual methods.

"Configuring IE2100 CNS Agents," describes how to configure Cisco Intelligence Engine 2100 (IE2100) Series Cisco Networking Services (CNS) embedded agents on your switch. By using the
IE2100 Series Configuration Registrar network management application, 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.

"Clustering Switches," describes switch clusters and the considerations for creating and maintaining them. The online help provides the CMS procedures for configuring switch clusters. Configuring switch clusters is most easily performed through CMS; therefore, CLI procedures are not provided. Cluster commands are described in the Catalyst 2950 Desktop Switch Command Reference.

"Administering the Switch," describes how to perform one-time operations to administer your switch. It describes how to prevent unauthorized access to your switch through the use of passwords, privilege levels, the Terminal Access Controller Access Control System Plus (TACACS+), the Remote Authentication Dial-In User Service (RADIUS) and the Secure Shell (SSH) Protocol. It also describes how to set the system date and time, set system name and prompt, create a login banner, and how to manage the MAC address and ARP tables.

"Configuring 802.1X Port-Based Authentication," describes how to configure 802.1X port-based authentication to prevent unauthorized devices (clients) from gaining access to the network. As LANs extend to hotels, airports, and corporate lobbies, insecure environments could be created.

"Configuring Interface Characteristics," defines the types of interfaces on the switch. It describes the interface global configuration command and provides procedures for configuring physical interfaces.

"Configuring STP," describes how to configure the Spanning Tree Protocol (STP) on your switch.

"Configuring RSTP and MSTP," describes how to configure the Cisco implementation of the IEEE 802.1W Rapid STP (RSTP) and the IEEE 802.1S Multiple STP (MSTP) on your switch. RSTP provides rapid convergence, and MSTP enables VLANs to be grouped into a spanning-tree instance.

"Configuring Optional Spanning-Tree Features," describes how to configure optional spanning-tree features that can be used when your switch is running the per-VLAN spanning-tree (PVST) or the MSTP.

"Configuring VLANs," describes how to create and maintain VLANs. It includes information about the VLAN database, VLAN configuration modes, extended-range VLANs, VLAN trunks, and the VLAN Membership Policy Server (VMPS).

"Configuring VTP," describes how to use the VLAN Trunking Protocol (VTP) VLAN database for managing VLANs. It includes VTP characteristics and configuration.

"Configuring Voice VLAN," describes how to configure voice VLAN on the switch for a connection to an IP phone.

"Configuring IGMP Snooping and MVR," describes how to configure Internet Group Management Protocol (IGMP) snooping. It also describes Multicast VLAN Registration (MVR), a local IGMP snooping feature available on the switch, and how to use IGMP filtering to control multicast group membership.

"Configuring Port-Based Traffic Control," describes how to reduce traffic storms by setting broadcast, multicast, and unicast storm-control threshold levels; how to protect ports from receiving traffic from other ports on a switch; how to configure port security by using secure MAC addresses; and how to set the aging time for all secure addresses.

"Configuring CDP," describes how to configure Cisco Discovery Protocol (CDP) on your switch.

"Configuring SPAN," describes how to configure Switch Port Analyzer (SPAN), which selects network traffic for analysis by a network analyzer such as a SwitchProbe device or other Remote Monitoring (RMON) probe. SPAN mirrors traffic received or sent (or both) on a source port, or traffic received on one or more source ports or source VLANs, to a destination port.

"Configuring System Message Logging," describes how to configure system message logging. It describes the message format, how to change the message display destination device, limit the type of messages sent, configure UNIX server syslog daemon, and define the UNIX system logging facility, and timestamp messages.

"Configuring SNMP," describes how to configure the Simple Network Management Protocol (SNMP). It describes how to configure community strings, enable trap managers and traps, set the agent contact and location information, and how to limit TFTP servers used through SNMP.

"Configuring Network Security with ACLs," provides the considerations and CLI procedures for configuring network security by using access control lists (ACLs). It describes how to apply ACLs to interfaces and provides examples. The online help provides the CMS procedures.

"Configuring QoS," provides the considerations and CLI procedures for configuring quality of service (QoS). With this feature, you can provide preferential treatment to certain types of traffic. The online help provides the CMS procedures.

"Configuring EtherChannels," describes how to bundle a set of individual ports into a single logical link on the interfaces.

"Troubleshooting," describes how to identify and resolve software problems related to the IOS software.

"Supported MIBs," lists the supported MIBs for this release and how to use FTP to access

the MIB files.


This guide uses these conventions to convey instructions and information:

Command descriptions use these conventions:

Commands and keywords are in boldface text.

Arguments for which you supply values are in italic.

Square brackets ([ ]) indicate optional elements.

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

Braces and vertical bars within square brackets ([{ | }]) indicate a required choice within an optional element.

Interactive examples use these conventions:

Terminal sessions and system displays are in screen font.

Information you enter is in boldface screen font.

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

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

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

Caution Means reader be careful. In this situation, you might do something that could result in equipment damage or loss of data.

Tip Means the following will help you solve a problem. The tips information might not be troubleshooting or even an action, but could be useful information.

Related Publications

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

You can order printed copies of documents with a DOC-xxxxxx= number from the sites and from the telephone numbers listed in the "Obtaining Documentation" section.

Release Notes for the Catalyst 2950 Switch (not orderable but is available on

Note Switch requirements and procedures for initial configurations and software upgrades tend to change and therefore appear only in the release notes. Before installing, configuring, or upgrading the switch, refer to the release notes on for the latest information.

Catalyst 2950 Desktop Switch Software Configuration Guide (order number DOC-7811380=)

Catalyst 2950 Desktop Switch Command Reference (order number DOC-7811381=)

Catalyst 2950 Desktop Switch System Message Guide (order number DOC-7814233=)

Catalyst 2950 Desktop Switch Hardware Installation Guide (order number DOC-7811157=)

Catalyst GigaStack Gigabit Interface Converter Hardware Installation Guide (order number DOC-786460=)

CWDM Passive Optical System Installation Note (not orderable but is available on

1000BASE-T GBIC Installation Notes (not orderable but is available on

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