Cisco 2950 - Catalyst Switch User manual

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Catalyst 2950 and Catalyst 2955 Switch
Software Configuration Guide
Cisco IOS Release 12.1(20)EA2
May 2004
Customer Order Number: DOC-7811380=
Text Part Number: 78-11380-10

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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
Copyright © 2001–2004 Cisco Systems, Inc. All rights reserved4

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CONTENTS
Preface xxix
Audience xxix
Purpose xxix
Conventions xxx
Related Publications xxxi
Obtaining Documentation xxxi
Cisco.com xxxi
Ordering Documentation xxxii
Documentation Feedback xxxii
Obtaining Technical Assistance xxxii
Cisco Technical Support Website xxxiii
Submitting a Service Request xxxiii
Definitions of Service Request Severity xxxiii
Obtaining AdditionalPublications andInformation xxxiv
CHAPTER 1Overview 1-1
Features 1-1
ManagementOptions 1-8
ManagementInterface Options 1-8
Advantages of Using CMS and Clustering Switches 1-9
Network Configuration Examples 1-10
Design Concepts for Using the Switch 1-10
Small to Medium-Sized Network Configuration 1-13
Collapsed Backbone and Switch Cluster Configuration 1-14
Hotel Network Configuration 1-15
Service-Provider Central-Office Configuration 1-18
Large Campus Configuration 1-19
Multidwelling Network Using Catalyst 2950 Switches 1-20
Long-Distance, High-Bandwidth Transport Configuration 1-22
Where to Go Next 1-22

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CHAPTER 2Using the Command-Line Interface 2-1
Cisco IOS Command Modes 2-1
Getting Help 2-3
Abbreviating Commands 2-4
Using no and default Forms ofCommands 2-4
Understanding CLI Messages 2-5
Using Command History 2-5
Changing the Command History Buffer Size 2-5
Recalling Commands 2-6
Disabling the Command History Feature 2-6
Using Editing Features 2-6
Enabling and Disabling Editing Features 2-6
Editing Commands through Keystrokes 2-7
Editing Command Lines that Wrap 2-8
Searching and Filtering Output of show and more Commands 2-9
Accessing the CLI 2-9
Accessing the CLI from a Browser 2-10
CHAPTER 3Configuring Catalyst 2955 Switch Alarms 3-1
Understanding Catalyst 2955 Switch Alarms 3-1
Global Status Monitoring Alarms 3-2
FCS ErrorHysteresis Threshold 3-2
Port Status Monitoring Alarms 3-3
Triggering Alarm Options 3-3
Configuring Catalyst 2955 Switch Alarms 3-4
Default Catalyst 2955 Switch Alarm Configuration 3-4
Configuring the Power Supply Alarm 3-5
Setting the Power Mode 3-5
Setting the Power Supply Alarm Options 3-5
Configuring the Switch Temperature Alarms 3-6
Setting a Secondary Temperature Threshold for the Switch 3-6
Associating the Temperature Alarms to a Relay 3-7
Configuring the FCS Bit Error Rate Alarm 3-7
Setting the FCS Error Threshold 3-8
Setting the FCS Error Hysteresis Threshold 3-8

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Configuring Alarm Profiles 3-9
Creating or Modifying an Alarm Profile 3-9
Attaching an Alarm Profile to a Specific Port 3-10
Enabling SNMP Traps 3-11
Displaying Catalyst 2955 Switch Alarms Status 3-11
CHAPTER 4Getting Started with CMS 4-1
Understanding CMS 4-1
Front Panel View 4-1
Topology View 4-2
CMS Menu Bar, Toolbar, and Feature Bar 4-2
Online Help 4-5
Configuration Modes 4-5
Guide Mode 4-5
Expert Mode 4-6
Wizards 4-6
Privilege Levels 4-7
Access to Older Switches in a Cluster 4-7
Configuring CMS 4-7
CMS Requirements 4-8
Minimum Hardware Configuration 4-8
Operating System and BrowserSupport 4-8
CMS Plug-In 4-9
Cross-Platform Considerations 4-9
HTTP Access to CMS 4-9
Specifying an HTTP Port (Nondefault Configuration Only) 4-10
Configuring an Authentication Method (Nondefault Configuration Only) 4-10
Displaying CMS 4-10
Launching CMS 4-10
Front Panel View 4-13
Topology View 4-14
CMS Icons 4-15
Where to Go Next 4-15

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CHAPTER 5Assigning the Switch IP Address and DefaultGateway 5-1
Understanding the Boot Process 5-1
Assigning Switch Information 5-2
Default Switch Information 5-3
Understanding DHCP-Based Autoconfiguration 5-3
DHCP Client Request Process 5-4
Configuring DHCP-Based Autoconfiguration 5-5
DHCP ServerConfiguration Guidelines 5-5
Configuring the TFTP Server 5-6
Configuring the DNS 5-7
Configuring the Relay Device 5-7
Obtaining Configuration Files 5-8
Example Configuration 5-9
Manually Assigning IP Information 5-10
Checking and Saving the Running Configuration 5-11
Modifying the Startup Configuration 5-11
Default Boot Configuration 5-12
Automatically Downloading a Configuration File 5-12
Specifying the Filename to Read and Write the System Configuration 5-12
Booting Manually 5-13
Booting a Specific Software Image 5-13
Controlling Environment Variables 5-14
Scheduling a Reload of the Software Image 5-16
Configuring a Scheduled Reload 5-16
Displaying Scheduled Reload Information 5-17
CHAPTER 6Configuring IE2100 CNS Agents 6-1
Understanding IE2100 Series Configuration Registrar Software 6-1
CNS Configuration Service 6-2
CNS Event Service 6-3
NameSpace Mapper 6-3
What You Should Know About ConfigID, DeviceID, and Host Name 6-3
ConfigID 6-3
DeviceID 6-4
Host Name and DeviceID 6-4
Using Host Name, DeviceID, and ConfigID 6-4

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Understanding CNS Embedded Agents 6-5
Initial Configuration 6-5
Incremental (Partial) Configuration 6-6
Synchronized Configuration 6-6
Configuring CNS Embedded Agents 6-6
Enabling Automated CNS Configuration 6-6
Enabling the CNS Event Agent 6-8
Enabling the CNS Configuration Agent 6-9
Enabling an Initial Configuration 6-9
Enabling a Partial Configuration 6-12
Displaying CNS Configuration 6-13
CHAPTER 7Clustering Switches 7-1
Understanding Switch Clusters 7-2
Command Switch Characteristics 7-3
Standby Command Switch Characteristics 7-3
Candidate Switch and Member Switch Characteristics 7-4
Planning a Switch Cluster 7-5
Automatic Discovery of Cluster Candidates and Members 7-5
Discovery through CDP Hops 7-6
Discovery through Non-CDP-Capable and Noncluster-Capable Devices 7-7
Discovery through the Same Management VLAN 7-8
Discovery through Different Management VLANs 7-9
Discovery of Newly Installed Switches 7-10
HSRP and Standby Command Switches 7-11
Virtual IP Addresses 7-12
Other Considerations for Cluster Standby Groups 7-12
Automatic Recovery of Cluster Configuration 7-14
IP Addresses 7-14
Host Names 7-15
Passwords 7-15
SNMP Community Strings 7-15
TACACS+ and RADIUS 7-16
Access Modes in CMS 7-16
ManagementVLAN 7-16
LRE Profiles 7-17
Availability of Switch-Specific Features in Switch Clusters 7-17

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Creating a Switch Cluster 7-18
Enabling a Command Switch 7-18
Adding Member Switches 7-19
Creating a Cluster Standby Group 7-21
Verifying a Switch Cluster 7-22
Using the CLI to Manage Switch Clusters 7-23
Catalyst 1900 and Catalyst 2820 CLI Considerations 7-24
Using SNMP to Manage Switch Clusters 7-24
CHAPTER 8Administering the Switch 8-1
Managing the System Time and Date 8-1
Understanding the System Clock 8-1
Understanding Network Time Protocol 8-2
Configuring NTP 8-3
Default NTP Configuration 8-4
Configuring NTP Authentication 8-4
Configuring NTP Associations 8-6
Configuring NTP Broadcast Service 8-7
Configuring NTP Access Restrictions 8-8
Configuring the Source IP Address for NTP Packets 8-10
Displaying the NTP Configuration 8-11
Configuring Time and Date Manually 8-11
Setting the System Clock 8-12
Displaying the Time and Date Configuration 8-12
Configuring the TimeZone 8-13
Configuring Summer Time (Daylight Saving Time) 8-14
Configuring a System Nameand Prompt 8-16
Default System Name and Prompt Configuration 8-16
Configuring a System Name 8-16
Configuring a System Prompt 8-17
Understanding DNS 8-17
Default DNS Configuration 8-18
Setting Up DNS 8-18
Displaying the DNS Configuration 8-19
Creating a Banner 8-19
Default Banner Configuration 8-19
Configuring a Message-of-the-Day Login Banner 8-20
Configuring a Login Banner 8-21

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Managing the MAC Address Table 8-21
Building the Address Table 8-22
MAC Addresses and VLANs 8-22
Default MAC Address Table Configuration 8-23
Changing the Address Aging Time 8-23
Removing Dynamic Address Entries 8-24
Configuring MAC Address Notification Traps 8-24
Adding and Removing Static Address Entries 8-26
Configuring Unicast MAC Address Filtering 8-27
Displaying Address Table Entries 8-28
Managing the ARP Table 8-28
CHAPTER 9Configuring Switch-Based Authentication 9-1
Preventing Unauthorized Access to Your Switch 9-1
Protecting Access to Privileged EXEC Commands 9-2
Default Password and Privilege Level Configuration 9-2
Setting or Changing a Static Enable Password 9-3
Protecting Enable and Enable Secret Passwords with Encryption 9-4
Disabling Password Recovery 9-5
Setting a Telnet Password for a Terminal Line 9-6
Configuring Username and Password Pairs 9-7
Configuring Multiple Privilege Levels 9-8
Setting the Privilege Level for a Command 9-8
Changing the Default Privilege Level for Lines 9-9
Logging into and Exiting a Privilege Level 9-10
Controlling Switch Access with TACACS+ 9-10
Understanding TACACS+ 9-10
TACACS+ Operation 9-12
Configuring TACACS+ 9-12
Default TACACS+ Configuration 9-13
Identifying the TACACS+ Server Host and Setting the Authentication Key 9-13
Configuring TACACS+ Login Authentication 9-14
Configuring TACACS+ Authorization for Privileged EXEC Access and Network Services 9-16
Starting TACACS+ Accounting 9-17
Displaying the TACACS+ Configuration 9-17
Controlling Switch Access with RADIUS 9-18
Understanding RADIUS 9-18
RADIUS Operation 9-19

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Configuring RADIUS 9-20
Default RADIUS Configuration 9-20
Identifying the RADIUS Server Host 9-21
Configuring RADIUS Login Authentication 9-23
Defining AAA Server Groups 9-25
Configuring RADIUS Authorization for User Privileged Access and Network Services 9-27
Starting RADIUS Accounting 9-28
Configuring Settings for All RADIUS Servers 9-29
Configuring the Switch to Use Vendor-Specific RADIUS Attributes 9-29
Configuring the Switch for Vendor-Proprietary RADIUS Server Communication 9-30
Displaying the RADIUS Configuration 9-31
Configuring the Switch for Local Authentication and Authorization 9-32
Configuring the Switch for Secure Shell 9-33
Understanding SSH 9-33
SSH Servers, Integrated Clients, and Supported Versions 9-33
Limitations 9-34
Configuring SSH 9-34
ConfigurationGuidelines 9-34
Cryptographic Software Image Guidelines 9-35
Setting Up the Switch to Run SSH 9-35
Configuring the SSH Server 9-36
Displaying the SSH Configuration and Status 9-37
CHAPTER 10 Configuring 802.1x Port-Based Authentication 10-1
Understanding 802.1x Port-Based Authentication 10-1
Device Roles 10-2
Authentication Initiation and Message Exchange 10-3
Ports in Authorized and Unauthorized States 10-4
802.1x Accounting 10-5
Supported Topologies 10-5
Using 802.1x with Port Security 10-6
Using 802.1x with Voice VLAN Ports 10-7
Using 802.1x with VLAN Assignment 10-7
Using 802.1x with Guest VLAN 10-8
Configuring 802.1x Authentication 10-9
Default 802.1x Configuration 10-9
802.1x Configuration Guidelines 10-10
Upgrading from a Previous Software Release 10-11
Enabling 802.1x Authentication 10-11

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Configuring the Switch-to-RADIUS-ServerCommunication 10-13
Enabling Periodic Re-Authentication 10-14
Manually Re-Authenticating a Client Connected to a Port 10-15
Changing the Quiet Period 10-15
Changing the Switch-to-Client Retransmission Time 10-15
Setting the Switch-to-Client Frame-Retransmission Number 10-16
Configuring the Host Mode 10-17
Configuring a Guest VLAN 10-18
Resetting the 802.1x Configuration to theDefault Values 10-18
Configuring 802.1x Authentication 10-19
Configuring 802.1x Accounting 10-20
Displaying 802.1x Statistics and Status 10-21
CHAPTER 11 Configuring Interface Characteristics 11-1
Understanding Interface Types 11-1
Access Ports 11-2
Trunk Ports 11-2
Port-Based VLANs 11-3
EtherChannelPort Groups 11-3
Connecting Interfaces 11-4
Using the Interface Command 11-4
Procedures for Configuring Interfaces 11-5
Configuring a Range of Interfaces 11-5
Configuring and Using Interface-Range Macros 11-7
Configuring EthernetInterfaces 11-8
Default Ethernet Interface Configuration 11-9
Configuring Interface Speed and Duplex Mode 11-10
ConfigurationGuidelines 11-10
Setting the Interface Speed and Duplex Parameters on a Non-LRE Switch Port 11-12
Setting the Interface Speed and Duplex Parameters on an LRE Switch Port 11-12
Configuring Media Types for Gigabit Ethernet Interfaces on LRE Switches 11-13
Configuring IEEE 802.3z Flow Control on Gigabit Ethernet Ports 11-13
Adding a Description for an Interface 11-14
Monitoring and Maintaining the Interfaces 11-15
Monitoring Interface and ControllerStatus 11-15
Clearing and Resetting Interfaces and Counters 11-16
Shutting Down and Restarting the Interface 11-17

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CHAPTER 12 Configuring Smartports Macros 12-1
Understanding Smartports Macros 12-1
Configuring Smartports Macros 12-2
Default Smartports Macro Configuration 12-2
Smartports Macro Configuration Guidelines 12-3
Creating Smartports Macros 12-4
Applying Smartports Macros 12-5
Applying Cisco-default Smartports Macros 12-6
Displaying Smartports Macros 12-8
CHAPTER 13 Configuring LRE 13-1
Understanding LRE Features 13-1
Ports on the Catalyst 2950 LRE Switches 13-1
LRE Links and LRE Profiles 13-2
LRE Profiles 13-2
LRE Sequences 13-5
CPE Ethernet Links 13-6
LRE Link Monitor 13-7
LRE Message Logging Process 13-8
Configuring LRE Ports 13-8
Default LRE Configuration 13-9
Environmental Guidelines for LRE Links 13-9
Guidelines for Using LRE Profiles 13-10
CPE Ethernet Link Guidelines 13-11
Guidelines for Configuring Cisco 575 LRE CPEs and 576 LRE 997 CPEs 13-11
Guidelines for Configuring Cisco 585 LRE CPEs 13-12
Assigning a GlobalProfile to All LRE Ports 13-12
Assigning a Profile to a SpecificLRE Port 13-13
Assigning a GlobalSequence to AllLRE Ports 13-13
Assigning a Sequence to a Specific LRE Port 13-14
Using Rate Selection to Automatically Assign Profiles 13-14
Precedence 13-15
Profile Locking 13-15
Link Qualification and SNR Margins 13-16
Configuring LRE Link Persistence 13-19
Configuring LRE Link Monitor 13-20
Configuring LRE Interleave 13-20
Configuring Upstream Power Back-Off 13-21

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Configuring CPE Toggle 13-22
Configuring Syslog Export 13-22
Upgrading LRE Switch Firmware 13-23
Configuring for an LRE Upgrade 13-24
Performing an LRE Upgrade 13-24
Global Configuration of LRE Upgrades 13-25
Controller Configuration of LRE Upgrades 13-25
LRE Upgrade Details 13-26
LRE Upgrade Example 13-26
Displaying LRE Status 13-27
CHAPTER 14 Configuring STP 14-1
Understanding Spanning-Tree Features 14-1
STP Overview 14-2
Spanning-Tree Topology and BPDUs 14-3
Bridge ID, Switch Priority, and Extended System ID 14-4
Spanning-Tree Interface States 14-4
Blocking State 14-6
Listening State 14-6
Learning State 14-6
Forwarding State 14-6
Disabled State 14-7
How a Switch orPort Becomes the Root Switch or Root Port 14-7
Spanning Tree and Redundant Connectivity 14-8
Spanning-Tree Address Management 14-8
Accelerated Aging to Retain Connectivity 14-8
Spanning-Tree Modes and Protocols 14-9
Supported Spanning-Tree Instances 14-9
Spanning-Tree Interoperability and Backward Compatibility 14-10
STP and IEEE 802.1Q Trunks 14-10
Configuring Spanning-Tree Features 14-11
Default Spanning-Tree Configuration 14-11
Spanning-Tree Configuration Guidelines 14-12
Changing the Spanning-Tree Mode 14-13
Disabling Spanning Tree 14-14
Configuring the Root Switch 14-14
Configuring a Secondary Root Switch 14-16
Configuring the Port Priority 14-17
Configuring the Path Cost 14-19

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Configuring the Switch Priority of a VLAN 14-20
Configuring Spanning-Tree Timers 14-21
Configuring the Hello Time 14-21
Configuring the Forwarding-Delay Time fora VLAN 14-22
Configuring the Maximum-Aging Time for a VLAN 14-22
Configuring Spanning Tree for Use in a Cascaded Stack 14-23
Displaying the Spanning-Tree Status 14-24
CHAPTER 15 Configuring MSTP 15-1
Understanding MSTP 15-2
Multiple Spanning-Tree Regions 15-2
IST, CIST, and CST 15-2
Operations Within an MST Region 15-3
Operations Between MST Regions 15-3
Hop Count 15-4
Boundary Ports 15-5
Interoperability with 802.1D STP 15-5
Understanding RSTP 15-6
Port Roles and the Active Topology 15-6
Rapid Convergence 15-7
Synchronization of Port Roles 15-8
Bridge Protocol Data Unit Format and Processing 15-9
Processing Superior BPDU Information 15-10
Processing Inferior BPDU Information 15-10
Topology Changes 15-10
Configuring MSTP Features 15-11
Default MSTP Configuration 15-12
MSTP Configuration Guidelines 15-12
Specifying the MST Region Configuration and Enabling MSTP 15-13
Configuring the Root Switch 15-14
Configuring a Secondary Root Switch 15-16
Configuring the Port Priority 15-17
Configuring the Path Cost 15-18
Configuring the Switch Priority 15-19
Configuring the Hello Time 15-19
Configuring the Forwarding-Delay Time 15-20
Configuring the Maximum-Aging Time 15-21
Configuring the Maximum-Hop Count 15-21

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Specifying the Link Type to Ensure Rapid Transitions 15-22
Restarting the Protocol Migration Process 15-22
Displaying the MST Configuration and Status 15-23
CHAPTER 16 Configuring Optional Spanning-Tree Features 16-1
Understanding Optional Spanning-Tree Features 16-1
Understanding Port Fast 16-2
Understanding BPDU Guard 16-2
Understanding BPDU Filtering 16-3
Understanding UplinkFast 16-3
Understanding Cross-Stack UplinkFast 16-5
How CSUF Works 16-5
Events that Cause Fast Convergence 16-7
Limitations 16-7
Connecting the Stack Ports 16-8
Understanding BackboneFast 16-9
Understanding EtherChannel Guard 16-11
Understanding Root Guard 16-11
Understanding Loop Guard 16-12
Configuring OptionalSpanning-Tree Features 16-12
Default OptionalSpanning-Tree Configuration 16-13
Optional Spanning-Tree Configuration Guidelines 16-13
Enabling Port Fast 16-13
Enabling BPDU Guard 16-14
Enabling BPDU Filtering 16-15
Enabling UplinkFast for Use with Redundant Links 16-16
Enabling Cross-Stack UplinkFast 16-17
Enabling BackboneFast 16-18
Enabling EtherChannelGuard 16-18
Enabling Root Guard 16-19
Enabling Loop Guard 16-19
Displaying the Spanning-Tree Status 16-20
CHAPTER 17 Configuring VLANs 17-1
Understanding VLANs 17-1
Supported VLANs 17-2
VLAN Port Membership Modes 17-3

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Configuring Normal-Range VLANs 17-4
Token Ring VLANs 17-5
Normal-Range VLAN Configuration Guidelines 17-5
VLAN Configuration Mode Options 17-6
VLAN Configuration in config-vlan Mode 17-6
VLAN Configuration in VLAN Configuration Mode 17-6
Saving VLAN Configuration 17-7
Default Ethernet VLAN Configuration 17-7
Creating or Modifying an Ethernet VLAN 17-8
Deleting a VLAN 17-10
Assigning Static-Access Ports to a VLAN 17-11
Configuring Extended-Range VLANs 17-12
Default VLAN Configuration 17-12
Extended-Range VLAN Configuration Guidelines 17-12
Creating an Extended-Range VLAN 17-13
Displaying VLANs 17-14
Configuring VLAN Trunks 17-15
Trunking Overview 17-15
802.1Q Configuration Considerations 17-16
Default Layer 2 Ethernet Interface VLAN Configuration 17-17
Configuring an Ethernet Interface as a Trunk Port 17-17
Interaction with Other Features 17-18
Configuring a Trunk Port 17-18
Defining the Allowed VLANs on a Trunk 17-19
Changing the Pruning-Eligible List 17-20
Configuring the Native VLAN for Untagged Traffic 17-21
Load Sharing Using STP 17-22
Load Sharing Using STP Port Priorities 17-22
Load Sharing Using STP Path Cost 17-24
Configuring VMPS 17-25
Understanding VMPS 17-25
Dynamic Port VLAN Membership 17-26
VMPS Database Configuration File 17-26
Default VMPS ClientConfiguration 17-27
VMPS Configuration Guidelines 17-27

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Configuring the VMPS Client 17-28
Entering the IP Address of the VMPS 17-28
Configuring Dynamic Access Ports on VMPS Clients 17-28
Reconfirming VLAN Memberships 17-29
Changing the Reconfirmation Interval 17-29
Changing the Retry Count 17-30
Monitoring the VMPS 17-30
Troubleshooting Dynamic Port VLAN Membership 17-31
VMPS Configuration Example 17-31
CHAPTER 18 Configuring VTP 18-1
Understanding VTP 18-1
The VTP Domain 18-2
VTP Modes 18-3
VTP Advertisements 18-3
VTP Version 2 18-4
VTP Pruning 18-4
Configuring VTP 18-6
Default VTP Configuration 18-6
VTP Configuration Options 18-7
VTP Configuration in Global Configuration Mode 18-7
VTP Configuration in VLAN Configuration Mode 18-7
VTP Configuration Guidelines 18-8
Domain Names 18-8
Passwords 18-8
Upgrading from Previous Software Releases 18-8
VTP Version 18-9
Configuration Requirements 18-9
Configuring a VTP Server 18-9
Configuring a VTP Client 18-11
Disabling VTP (VTP Transparent Mode) 18-12
Enabling VTP Version 2 18-13
Enabling VTP Pruning 18-14
Adding a VTP Client Switch to a VTP Domain 18-14
Monitoring VTP 18-16

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CHAPTER 19 Configuring Voice VLAN 19-1
Understanding Voice VLAN 19-1
Configuring Voice VLAN 19-2
Default Voice VLAN Configuration 19-2
Voice VLAN Configuration Guidelines 19-3
Configuring a Port to Connect to aCisco 7960 IP Phone 19-3
Configuring Ports to Carry Voice Traffic in 802.1Q Frames 19-4
Configuring Ports to Carry Voice Traffic in 802.1p Priority-Tagged Frames 19-4
Overriding the CoS Priority of Incoming Data Frames 19-5
Configuring the IP Phone to Trust the CoS Priority of Incoming Data Frames 19-6
Displaying Voice VLAN 19-6
CHAPTER 20 Configuring DHCP Features 20-1
Understanding DHCP Features 20-1
DHCP Server 20-2
DHCP Relay Agent 20-2
DHCP Snooping 20-2
Option-82 Data Insertion 20-3
Configuring DHCP Features 20-5
Default DHCP Configuration 20-5
DHCP Snooping Configuration Guidelines 20-6
Configuring the DHCP Server 20-6
Enabling DHCP Snooping and Option 82 20-7
Displaying DHCP Information 20-8
Displaying a Binding Table 20-8
Displaying the DHCPSnooping Configuration 20-8
CHAPTER 21 Configuring IGMP Snooping and MVR 21-1
Understanding IGMP Snooping 21-1
IGMP Versions 21-2
Joining a Multicast Group 21-3
Leaving a Multicast Group 21-4
Immediate-Leave Processing 21-5
IGMP Report Suppression 21-5
Source-Only Networks 21-5

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Configuring IGMP Snooping 21-6
Default IGMP Snooping Configuration 21-6
Enabling or Disabling IGMP Snooping 21-7
Setting the Snooping Method 21-8
Configuring a Multicast Router Port 21-9
Configuring a Host Statically to Join a Group 21-10
Enabling IGMP Immediate-Leave Processing 21-10
Disabling IGMP Report Suppression 21-11
Disabling IP Multicast-Source-Only Learning 21-11
Configuring the Aging Time 21-12
Displaying IGMP Snooping Information 21-13
Understanding Multicast VLAN Registration 21-14
Using MVR in a Multicast Television Application 21-15
Configuring MVR 21-17
Default MVR Configuration 21-17
MVR Configuration Guidelines and Limitations 21-17
Configuring MVR Global Parameters 21-18
Configuring MVR Interfaces 21-19
Displaying MVR Information 21-21
Configuring IGMP Filtering and Throttling 21-21
Default IGMP Filtering and Throttling Configuration 21-22
Configuring IGMP Profiles 21-22
Applying IGMP Profiles 21-24
Setting the Maximum Number of IGMP Groups 21-25
Configuring the IGMP Throttling Action 21-25
Displaying IGMP Filtering and Throttling Configuration 21-27
CHAPTER 22 Configuring Port-Based Traffic Control 22-1
Configuring Storm Control 22-1
Understanding Storm Control 22-2
Default Storm Control Configuration 22-2
Enabling Storm Control 22-2
Disabling Storm Control 22-4
Configuring Protected Ports 22-4
Configuring Port Blocking 22-5
Blocking Flooded Traffic on an Interface 22-5
Resuming Normal Forwarding on a Port 22-6

Contents
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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide 78-11380-10
Configuring Port Security 22-7
Understanding Port Security 22-7
Secure MAC Addresses 22-7
Security Violations 22-8
Default Port Security Configuration 22-9
Port Security Configuration Guidelines 22-9
Enabling and Configuring Port Security 22-10
Enabling and Configuring Port Security Aging 22-12
Displaying Port-Based Traffic ControlSettings 22-13
CHAPTER 23 Configuring UDLD 23-1
Understanding UDLD 23-1
Modes of Operation 23-1
Methods to Detect Unidirectional Links 23-2
Configuring UDLD 23-4
Default UDLD Configuration 23-4
Configuration Guidelines 23-4
Enabling UDLD Globally 23-5
Enabling UDLD on an Interface 23-5
Resetting an Interface Shut Down by UDLD 23-6
Displaying UDLD Status 23-7
CHAPTER 24 Configuring CDP 24-1
Understanding CDP 24-1
Configuring CDP 24-2
Default CDP Configuration 24-2
Configuring the CDP Characteristics 24-2
Disabling and Enabling CDP 24-3
Disabling and Enabling CDP on an Interface 24-4
Monitoring and Maintaining CDP 24-5