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Catalyst 3550 Multilayer Switch Software Configuration GuideCisco IOS Release 12.1(13)EA1March 2003

Customer Order Number: DOC-7811194=Text Part Number: 78-11194-07

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

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Catalyst 3550 Multilayer Switch Software Configuration GuideCopyright 20012003, Cisco Systems, Inc.All rights reserved.

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Catalys78-11194-07

Where to Go Next 1-18

C H A P T E R 2 Using the Command-Line Interface 2-1

IOS Command Modes 2-1

Getting Help 2-3

C O N T E N T S

Preface xxxiii

Audience xxxiii

Purpose xxxiii

Conventions xxxiv

Related Publications xxxiv

Obtaining Documentation xxxvCisco.com xxxvDocumentation CD-ROM xxxvOrdering Documentation xxxvDocumentation Feedback xxxvi

Obtaining Technical Assistance xxxviCisco.com xxxviTechnical Assistance Center xxxvii

Cisco TAC Website xxxviiCisco TAC Escalation Center xxxvii

Obtaining Additional Publications and Information xxxviii

C H A P T E R 1 Overview 1-1

Features 1-1

Management Options 1-7Management Interface Options 1-7Advantages of Using CMS and Clustering Switches 1-7

Network Configuration Examples 1-8Design Concepts for Using the Switch 1-9Small to Medium-Sized Network Using Mixed Switches 1-12Large Network Using Only Catalyst 3550 Switches 1-14Multidwelling Network Using Catalyst 3550 Switches 1-15Long-Distance, High-Bandwidth Transport Configuration 1-17iiit 3550 Multilayer Switch Software Configuration Guide

Contents

Abbreviating Commands 2-4

Using no and default Forms of Commands 2-4

Understanding CLI Messages 2-5

Using Command History 2-5Changing the Command History Buffer Size 2-5Recalling Commands 2-6Disabling the Command History Feature 2-6

Using Editing Features 2-6Enabling and Disabling Editing Features 2-7Editing Commands through Keystrokes 2-7Editing 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

C H A P T E R 3 Getting Started with CMS 3-1

Features 3-2

Front Panel View 3-3Cluster Tree 3-5Front-Panel Images 3-6Redundant Power System LED 3-7Port Modes and LEDs 3-8VLAN Membership Modes 3-9

Topology View 3-10Topology Icons and Labels 3-11Device and Link Labels 3-12Colors in the Topology View 3-12Topology Display Options 3-13

Menus and Toolbar 3-13Menu Bar 3-13Toolbar 3-19Front Panel View Popup Menus 3-20

Device Popup Menu 3-20Port Popup Menu 3-21

Topology View Popup Menus 3-21Link Popup Menu 3-21

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Interaction Modes 3-24

Contents

Guide Mode 3-24Expert Mode 3-24Wizards 3-25Tool Tips 3-25Online Help 3-25

CMS Window Components 3-26Host Name List 3-27Tabs, Lists, and Tables 3-28Filter Editor 3-28Buttons 3-28Green Border Around a Field or Cell 3-28Red Border Around a Field 3-29

Accessing CMS 3-29Access Modes in CMS 3-30HTTP Access to CMS 3-31

Saving Your Configuration 3-31

Restoring Your Configuration 3-32

CMS Preferences 3-32

Using Different Versions of CMS 3-32

Where to Go Next 3-33

C H A P T E R 4 Assigning the Switch IP Address and Default Gateway 4-1

Understanding the Boot Process 4-1

Assigning Switch Information 4-2Default Switch Information 4-3Understanding DHCP-Based Autoconfiguration 4-3

DHCP Client Request Process 4-4Configuring the DHCP Server 4-5Configuring the TFTP Server 4-5Configuring the DNS 4-6Configuring the Relay Device 4-6Obtaining Configuration Files 4-7Example Configuration 4-8

Manually Assigning IP Information 4-10

Checking and Saving the Running Configuration 4-10

Modifying the Startup Configuration 4-12Default Boot Configuration 4-12vCatalyst 3550 Multilayer Switch Software Configuration Guide

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Automatically Downloading a Configuration File 4-12

Contents

Specifying the Filename to Read and Write the System Configuration 4-13Booting Manually 4-13Booting a Specific Software Image 4-14Controlling Environment Variables 4-15

Scheduling a Reload of the Software Image 4-17Configuring a Scheduled Reload 4-17Displaying Scheduled Reload Information 4-18

C H A P T E R 5 Configuring IE2100 CNS Agents 5-1

Understanding IE2100 Series Configuration Registrar Software 5-1CNS Configuration Service 5-2CNS Event Service 5-3

NameSpace Mapper 5-3What You Should Know About ConfigID, DeviceID, and Host Name 5-3

ConfigID 5-3DeviceID 5-4Host Name and DeviceID 5-4Using Host Name, DeviceID, and ConfigID 5-4

Understanding CNS Embedded Agents 5-5Initial Configuration 5-5Incremental (Partial) Configuration 5-6Synchronized Configuration 5-6

Configuring CNS Embedded Agents 5-6Enabling Automated CNS Configuration 5-6Enabling the CNS Event Agent 5-8Enabling the CNS Configuration Agent 5-9

Enabling an Initial Configuration 5-9Enabling a Partial Configuration 5-12

Displaying CNS Configuration 5-13

C H A P T E R 6 Clustering Switches 6-1

Understanding Switch Clusters 6-2Command Switch Characteristics 6-3Standby Command Switch Characteristics 6-3Candidate Switch and Member Switch Characteristics 6-4

Planning a Switch Cluster 6-5Automatic Discovery of Cluster Candidates and Members 6-5

Discovery through CDP Hops 6-6viCatalyst 3550 Multilayer Switch Software Configuration Guide

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Discovery through Non-CDP-Capable and Noncluster-Capable Devices 6-6

Contents

Discovery through Different VLANs 6-7Discovery through the Same Management VLAN 6-8Discovery through Different Management VLANs 6-9Discovery through Routed Ports 6-10Discovery of Newly Installed Switches 6-11

HSRP and Standby Command Switches 6-12Virtual IP Addresses 6-13Other Considerations for Cluster Standby Groups 6-13Automatic Recovery of Cluster Configuration 6-15

IP Addresses 6-16Host Names 6-16Passwords 6-16SNMP Community Strings 6-17TACACS+ and RADIUS 6-17Access Modes in CMS 6-17LRE Profiles 6-18Availability of Switch-Specific Features in Switch Clusters 6-18

Creating a Switch Cluster 6-18Enabling a Command Switch 6-19Adding Member Switches 6-20Creating a Cluster Standby Group 6-22Verifying a Switch Cluster 6-24

Using the CLI to Manage Switch Clusters 6-25Catalyst 1900 and Catalyst 2820 CLI Considerations 6-25

Using SNMP to Manage Switch Clusters 6-26

C H A P T E R 7 Administering the Switch 7-1

Managing the System Time and Date 7-1Understanding the System Clock 7-1Understanding Network Time Protocol 7-2Configuring NTP 7-3

Default NTP Configuration 7-4Configuring NTP Authentication 7-4Configuring NTP Associations 7-5Configuring NTP Broadcast Service 7-6Configuring NTP Access Restrictions 7-7Configuring the Source IP Address for NTP Packets 7-9Displaying the NTP Configuration 7-10viiCatalyst 3550 Multilayer Switch Software Configuration Guide

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Configuring Time and Date Manually 7-10

Contents

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

Configuring a System Name and Prompt 7-15Default System Name and Prompt Configuration 7-15Configuring a System Name 7-15Configuring a System Prompt 7-16Understanding DNS 7-16

Default DNS Configuration 7-17Setting Up DNS 7-17Displaying the DNS Configuration 7-18

Creating a Banner 7-18Default Banner Configuration 7-18Configuring a Message-of-the-Day Login Banner 7-19Configuring a Login Banner 7-20

Managing the MAC Address Table 7-20Building the Address Table 7-21MAC Addresses and VLANs 7-21Default MAC Address Table Configuration 7-22Changing the Address Aging Time 7-22Removing Dynamic Address Entries 7-23Configuring MAC Address Notification Traps 7-23Adding and Removing Static Address Entries 7-25Adding and Removing Secure Addresses 7-26Displaying Address Table Entries 7-26

Optimizing System Resources for User-Selected Features 7-27Using the Templates 7-28

C H A P T E R 8 Configuring Switch-Based Authentication 8-1

Preventing Unauthorized Access to Your Switch 8-1

Protecting Access to Privileged EXEC Commands 8-2Default Password and Privilege Level Configuration 8-2Setting or Changing a Static Enable Password 8-3Protecting Enable and Enable Secret Passwords with Encryption 8-4Disabling Password Recovery 8-5Setting a Telnet Password for a Terminal Line 8-6Configuring Username and Password Pairs 8-7viiiCatalyst 3550 Multilayer Switch Software Configuration Guide

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Configuring Multiple Privilege Levels 8-8

Contents

Setting the Privilege Level for a Command 8-8Changing the Default Privilege Level for Lines 8-9Logging into and Exiting a Privilege Level 8-10

Controlling Switch Access with TACACS+ 8-10Understanding TACACS+ 8-10TACACS+ Operation 8-12Configuring TACACS+ 8-12

Default TACACS+ Configuration 8-13Identifying the TACACS+ Server Host and Setting the Authentication Key 8-13Configuring TACACS+ Login Authentication 8-14Configuring TACACS+ Authorization for Privileged EXEC Access and Network Services 8-16Starting TACACS+ Accounting 8-17

Displaying the TACACS+ Configuration 8-17

Controlling Switch Access with RADIUS 8-18Understanding RADIUS 8-18RADIUS Operation 8-19Configuring RADIUS 8-20

Default RADIUS Configuration 8-20Identifying the RADIUS Server Host 8-20Configuring RADIUS Login Authentication 8-23Defining AAA Server Groups 8-25Configuring RADIUS Authorization for User Privileged Access and Network Services 8-27Starting RADIUS Accounting 8-28Configuring Settings for All RADIUS Servers 8-29Configuring the Switch to Use Vendor-Specific RADIUS Attributes 8-29Configuring the Switch for Vendor-Proprietary RADIUS Server Communication 8-31

Displaying the RADIUS Configuration 8-31

Controlling Switch Access with Kerberos 8-32Understanding Kerberos 8-32Kerberos Operation 8-34

Authenticating to a Boundary Switch 8-35Obtaining a TGT from a KDC 8-35Authenticating to Network Services 8-35

Configuring Kerberos 8-35

Configuring the Switch for Local Authentication and Authorization 8-36

Configuring the Switch for Secure Shell 8-37Understanding SSH 8-37Configuring SSH 8-38ixCatalyst 3550 Multilayer Switch Software Configuration Guide

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Contents

C H A P T E R 9 Configuring 802.1X Port-Based Authentication 9-1

Understanding 802.1X Port-Based Authentication 9-1Device Roles 9-2Authentication Initiation and Message Exchange 9-3Ports in Authorized and Unauthorized States 9-4Voice VLAN Ports 9-5Using 802.1X with Port Security 9-5Using 802.1X with Per-User ACLs 9-6Using 802.1X with VLAN Assignment 9-7Supported Topologies 9-8

Configuring 802.1X Authentication 9-8Default 802.1X Configuration 9-9802.1X Configuration Guidelines 9-10Enabling 802.1X Authentication 9-10Configuring the Switch-to-RADIUS-Server Communication 9-12Enabling Periodic Re-Authentication 9-13Manually Re-Authenticating a Client Connected to a Port 9-14Changing the Quiet Period 9-14Changing the Switch-to-Client Retransmission Time 9-15Setting the Switch-to-Client Frame-Retransmission Number 9-15Enabling Multiple Hosts 9-16Resetting the 802.1X Configuration to the Default Values 9-17

Displaying 802.1X Statistics and Status 9-17

C H A P T E R 10 Configuring Interface Characteristics 10-1

Understanding Interface Types 10-1Port-Based VLANs 10-2Switch Ports 10-2

Access Ports 10-3Trunk Ports 10-3Tunnel Ports 10-4

Switch Virtual Interfaces 10-4Routed Ports 10-4EtherChannel Port Groups 10-5Connecting Interfaces 10-5

Using the Interface Command 10-7Procedures for Configuring Interfaces 10-7Configuring a Range of Interfaces 10-8xCatalyst 3550 Multilayer Switch Software Configuration Guide

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Configuring and Using Interface Range Macros 10-10

Contents

Configuring Layer 2 Interfaces 10-11Default Layer 2 Ethernet Interface Configuration 10-12Configuring Interface Speed and Duplex Mode 10-13

Configuration Guidelines 10-13Setting the Interface Speed and Duplex Parameters 10-14Configuring Inline Power on the Catalyst 3550-24PWR Ports 10-14

Configuring IEEE 802.3X Flow Control 10-15Adding a Description for an Interface 10-17

Configuring Layer 3 Interfaces 10-18

Monitoring and Maintaining the Interfaces 10-19Monitoring Interface and Controller Status 10-19Clearing and Resetting Interfaces and Counters 10-21Shutting Down and Restarting the Interface 10-22

C H A P T E R 11 Configuring VLANs 11-1

Understanding VLANs 11-1Supported VLANs 11-2VLAN Port Membership Modes 11-3

Configuring Normal-Range VLANs 11-4Token Ring VLANs 11-5Normal-Range VLAN Configuration Guidelines 11-5VLAN Configuration Mode Options 11-6

VLAN Configuration in config-vlan Mode 11-6VLAN Configuration in VLAN Configuration Mode 11-6

Saving VLAN Configuration 11-7Default Ethernet VLAN Configuration 11-7Creating or Modifying an Ethernet VLAN 11-8Deleting a VLAN 11-10Assigning Static-Access Ports to a VLAN 11-11

Configuring Extended-Range VLANs 11-12Default VLAN Configuration 11-12Extended-Range VLAN Configuration Guidelines 11-12Creating an Extended-Range VLAN 11-13Creating an Extended-Range VLAN with an Internal VLAN ID 11-14

Displaying VLANs 11-15

Configuring VLAN Trunks 11-16Trunking Overview 11-16

Encapsulation Types 11-18xiCatalyst 3550 Multilayer Switch Software Configuration Guide

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802.1Q Configuration Considerations 11-18

Contents

Default Layer 2 Ethernet Interface VLAN Configuration 11-18Configuring an Ethernet Interface as a Trunk Port 11-19

Interaction with Other Features 11-19Configuring a Trunk Port 11-20Defining the Allowed VLANs on a Trunk 11-21Changing the Pruning-Eligible List 11-22Configuring the Native VLAN for Untagged Traffic 11-22

Load Sharing Using STP 11-23Load Sharing Using STP Port Priorities 11-24Load Sharing Using STP Path Cost 11-25

Configuring VMPS 11-27Understanding VMPS 11-27

Dynamic Port VLAN Membership 11-28VMPS Database Configuration File 11-28

Default VMPS Configuration 11-30VMPS Configuration Guidelines 11-30Configuring the VMPS Client 11-31

Entering the IP Address of the VMPS 11-31Configuring Dynamic Access Ports on VMPS Clients 11-31Reconfirming VLAN Memberships 11-32Changing the Reconfirmation Interval 11-32Changing the Retry Count 11-33

Monitoring the VMPS 11-33Troubleshooting Dynamic Port VLAN Membership 11-34VMPS Configuration Example 11-34

C H A P T E R 12 Configuring VTP 12-1

Understanding VTP 12-1The VTP Domain 12-2VTP Modes 12-3VTP Advertisements 12-3VTP Version 2 12-4VTP Pruning 12-4

Configuring VTP 12-6Default VTP Configuration 12-6VTP Configuration Options 12-7

VTP Configuration in Global Configuration Mode 12-7VTP Configuration in VLAN Configuration Mode 12-7xiiCatalyst 3550 Multilayer Switch Software Configuration Guide

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VTP Configuration Guidelines 12-8

Contents

Domain Names 12-8Passwords 12-8VTP Version 12-8Configuration Requirements 12-9

Configuring a VTP Server 12-9Configuring a VTP Client 12-10Disabling VTP (VTP Transparent Mode) 12-11Enabling VTP Version 2 12-12Enabling VTP Pruning 12-13Adding a VTP Client Switch to a VTP Domain 12-14

Monitoring VTP 12-15

C H A P T E R 13 Configuring Voice VLAN 13-1

Understanding Voice VLAN 13-1

Configuring Voice VLAN 13-2Default Voice VLAN Configuration 13-2Voice VLAN Configuration Guidelines 13-3Configuring a Port to Connect to a Cisco 7960 IP Phone 13-3

Configuring Ports to Carry Voice Traffic in 802.1Q Frames 13-4Configuring Ports to Carry Voice Traffic in 802.1P Priority-Tagged Frames 13-4Overriding the CoS Priority of Incoming Data Frames 13-5Configuring the IP Phone to Trust the CoS Priority of Incoming Data Frames 13-6

Displaying Voice VLAN 13-6

C H A P T E R 14 Configuring 802.1Q and Layer 2 Protocol Tunneling 14-1

Understanding 802.1Q Tunneling 14-1

Configuring 802.1Q Tunneling 14-4Default 802.1Q Tunneling Configuration 14-4802.1Q Tunneling Configuration Guidelines 14-4

Native VLANs 14-4System MTU 14-5

802.1Q Tunneling and Other Features 14-5Configuring an 802.1Q Tunneling Port 14-6

Understanding Layer 2 Protocol Tunneling 14-7

Configuring Layer 2 Protocol Tunneling 14-9Default Layer 2 Protocol Tunneling Configuration 14-9Layer 2 Protocol Tunneling Configuration Guidelines 14-10Configuring Layer 2 Tunneling Characteristics 14-11xiiiCatalyst 3550 Multilayer Switch Software Configuration Guide

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Contents

Monitoring and Maintaining Tunneling Status 14-12

C H A P T E R 15 Configuring STP 15-1

Understanding Spanning-Tree Features 15-1STP Overview 15-2Supported Spanning-Tree Instances 15-2Bridge Protocol Data Units 15-2Election of the Root Switch 15-3Bridge ID, Switch Priority, and Extended System ID 15-4Spanning-Tree Timers 15-4Creating the Spanning-Tree Topology 15-5Spanning-Tree Interface States 15-5

Blocking State 15-7Listening State 15-7Learning State 15-7Forwarding State 15-7Disabled State 15-8

Spanning-Tree Address Management 15-8STP and IEEE 802.1Q Trunks 15-8VLAN-Bridge STP 15-8Spanning Tree and Redundant Connectivity 15-9Accelerated Aging to Retain Connectivity 15-9

Configuring Spanning-Tree Features 15-10Default STP Configuration 15-10STP Configuration Guidelines 15-11Disabling STP 15-11Configuring the Root Switch 15-12Configuring a Secondary Root Switch 15-14Configuring the Port Priority 15-15Configuring the Path Cost 15-16Configuring the Switch Priority of a VLAN 15-17Configuring the Hello Time 15-18Configuring the Forwarding-Delay Time for a VLAN 15-19Configuring the Maximum-Aging Time for a VLAN 15-19Configuring STP for Use in a Cascaded Stack 15-20

Displaying the Spanning-Tree Status 15-20

C H A P T E R 16 Configuring RSTP and MSTP 16-1xivCatalyst 3550 Multilayer Switch Software Configuration Guide

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Understanding RSTP 16-2

Contents

Spanning-Tree Instances Using RSTP 16-2Port Roles and the Active Topology 16-2Rapid Convergence 16-3Synchronization of Port Roles 16-4Bridge Protocol Data Unit Format and Processing 16-5

Processing Superior BPDU Information 16-6Processing Inferior BPDU Information 16-6

Topology Changes 16-6

Understanding MSTP 16-7Multiple Spanning-Tree Regions 16-7IST, CIST, and CST 16-8

Operations Within an MST Region 16-8Operations Between MST Regions 16-9

Hop Count 16-10Boundary Ports 16-10

Interoperability with 802.1D STP 16-11

Configuring RSTP and MSTP Features 16-11Default RSTP and MSTP Configuration 16-12RSTP and MSTP Configuration Guidelines 16-12Specifying the MST Region Configuration and Enabling MSTP 16-13Configuring the Root Switch 16-14Configuring a Secondary Root Switch 16-16Configuring the Port Priority 16-17Configuring the Path Cost 16-18Configuring the Switch Priority 16-19Configuring the Hello Time 16-19Configuring the Forwarding-Delay Time 16-20Configuring the Maximum-Aging Time 16-21Configuring the Maximum-Hop Count 16-21Specifying the Link Type to Ensure Rapid Transitions 16-22Restarting the Protocol Migration Process 16-22

Displaying the MST Configuration and Status 16-23

C H A P T E R 17 Configuring Optional Spanning-Tree Features 17-1

Understanding Optional Spanning-Tree Features 17-1Understanding Port Fast 17-2Understanding BPDU Guard 17-3Understanding BPDU Filtering 17-3xvCatalyst 3550 Multilayer Switch Software Configuration Guide

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Understanding UplinkFast 17-4

Contents

Understanding Cross-Stack UplinkFast 17-5How CSUF Works 17-6Events that Cause Fast Convergence 17-7Limitations 17-8Connecting the Stack Ports 17-8

Understanding BackboneFast 17-10Understanding EtherChannel Guard 17-12Understanding Root Guard 17-12Understanding Loop Guard 17-13

Configuring Optional Spanning-Tree Features 17-14Default Optional Spanning-Tree Configuration 17-14Enabling Port Fast 17-14Enabling BPDU Guard 17-15Enabling BPDU Filtering 17-16Enabling UplinkFast for Use with Redundant Links 17-17Enabling Cross-Stack UplinkFast 17-18Enabling BackboneFast 17-19Enabling EtherChannel Guard 17-19Enabling Root Guard 17-20Enabling Loop Guard 17-20

Displaying the Spanning-Tree Status 17-21

C H A P T E R 18 Configuring the DHCP Option 82 for Subscriber Identification 18-1

Understanding the DHCP and Option 82 Subscriber Identification 18-1

Configuring the DHCP Relay Agent 18-3Default DHCP Configuration 18-3DHCP Configuration Guidelines 18-4Enabling the DHCP Relay Agent and Relay Agent Information 18-4Validating the Relay Agent Information Option 82 18-4Configuring the Reforwarding Policy 18-5Specifying the Packet Forwarding Address 18-5Suppressing DHCP Broadcasts and Achieving Port-to-Port Isolation 18-7

Displaying the DHCP Information 18-7

C H A P T E R 19 Configuring IGMP Snooping and MVR 19-1

Understanding IGMP Snooping 19-1Joining a Multicast Group 19-2Leaving a Multicast Group 19-4xviCatalyst 3550 Multilayer Switch Software Configuration Guide

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Immediate-Leave Processing 19-4

Contents

Configuring IGMP Snooping 19-5Default IGMP Snooping Configuration 19-5Enabling or Disabling IGMP Snooping 19-5Setting the Snooping Method 19-6Configuring a Multicast Router Port 19-7Configuring a Host Statically to Join a Group 19-8Enabling IGMP Immediate-Leave Processing 19-9

Displaying IGMP Snooping Information 19-9

Understanding Multicast VLAN Registration 19-12Using MVR in a Multicast Television Application 19-12

Configuring MVR 19-14Default MVR Configuration 19-14MVR Configuration Guidelines and Limitations 19-15Configuring MVR Global Parameters 19-15Configuring MVR Interfaces 19-16

Displaying MVR Information 19-18

Configuring IGMP Filtering 19-19Default IGMP Filtering Configuration 19-20Configuring IGMP Profiles 19-20Applying IGMP Profiles 19-21Setting the Maximum Number of IGMP Groups 19-22

Displaying IGMP Filtering Configuration 19-23

C H A P T E R 20 Configuring Port-Based Traffic Control 20-1

Configuring Storm Control 20-1Understanding Storm Control 20-1Default Storm Control Configuration 20-3Enabling Storm Control 20-3Disabling Storm Control 20-4

Configuring Protected Ports 20-5

Configuring Port Blocking 20-6Blocking Flooded Traffic on an Interface 20-6Resuming Normal Forwarding on a Port 20-7

Configuring Port Security 20-7Understanding Port Security 20-8

Secure MAC Addresses 20-8Security Violations 20-8

Default Port Security Configuration 20-9xviiCatalyst 3550 Multilayer Switch Software Configuration Guide

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Contents

Port Security Configuration Guidelines 20-9Enabling and Configuring Port Security 20-10Enabling and Configuring Port Security Aging 20-12

Displaying Port-Based Traffic Control Settings 20-14

C H A P T E R 21 Configuring CDP 21-1

Understanding CDP 21-1

Configuring CDP 21-2Default CDP Configuration 21-2Configuring the CDP Characteristics 21-2Disabling and Enabling CDP 21-3Disabling and Enabling CDP on an Interface 21-4

Monitoring and Maintaining CDP 21-5

C H A P T E R 22 Configuring UDLD 22-1

Understanding UDLD 22-1

Configuring UDLD 22-3Default UDLD Configuration 22-3Enabling UDLD Globally 22-4Enabling UDLD on an Interface 22-4Resetting an Interface Shut Down by UDLD 22-5

Displaying UDLD Status 22-6

C H A P T E R 23 Configuring SPAN and RSPAN 23-1

Understanding SPAN and RSPAN 23-1SPAN and RSPAN Concepts and Terminology 23-3

SPAN Session 23-3Traffic Types 23-3Source Port 23-4Destination Port 23-5Reflector Port 23-5VLAN-Based SPAN 23-6SPAN Traffic 23-6

SPAN and RSPAN Interaction with Other Features 23-7SPAN and RSPAN Session Limits 23-8Default SPAN and RSPAN Configuration 23-8

Configuring SPAN 23-8xviiiCatalyst 3550 Multilayer Switch Software Configuration Guide

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SPAN Configuration Guidelines 23-9

Contents

Creating a SPAN Session and Specifying Ports to Monitor 23-10Creating a SPAN Session and Enabling Ingress Traffic 23-11Removing Ports from a SPAN Session 23-13Specifying VLANs to Monitor 23-14Specifying VLANs to Filter 23-15

Configuring RSPAN 23-16RSPAN Configuration Guidelines 23-16Creating an RSPAN Session 23-17Creating an RSPAN Destination Session 23-18Creating an RSPAN Destination Session and Enabling Ingress Traffic 23-19Removing Ports from an RSPAN Session 23-20Specifying VLANs to Monitor 23-21Specifying VLANs to Filter 23-22

Displaying SPAN and RSPAN Status 23-23

C H A P T E R 24 Configuring RMON 24-1

Understanding RMON 24-1

Configuring RMON 24-2Default RMON Configuration 24-3Configuring RMON Alarms and Events 24-3Configuring RMON Collection on an Interface 24-5

Displaying RMON Status 24-6

C H A P T E R 25 Configuring System Message Logging 25-1

Understanding System Message Logging 25-1

Configuring System Message Logging 25-2System Log Message Format 25-2Default System Message Logging Configuration 25-3Disabling and Enabling Message Logging 25-4Setting the Message Display Destination Device 25-4Synchronizing Log Messages 25-6Enabling and Disabling Timestamps on Log Messages 25-7Enabling and Disabling Sequence Numbers in Log Messages 25-8Defining the Message Severity Level 25-8Limiting Syslog Messages Sent to the History Table and to SNMP 25-10Configuring UNIX Syslog Servers 25-10

Logging Messages to a UNIX Syslog Daemon 25-11Configuring the UNIX System Logging Facility 25-11xixCatalyst 3550 Multilayer Switch Software Configuration Guide

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Displaying the Logging Configuration 25-12

Contents

C H A P T E R 26 Configuring SNMP 26-1

Understanding SNMP 26-1SNMP Versions 26-2SNMP Manager Functions 26-3SNMP Agent Functions 26-4SNMP Community Strings 26-4Using SNMP to Access MIB Variables 26-4SNMP Notifications 26-5

Configuring SNMP 26-5Default SNMP Configuration 26-6SNMP Configuration Guidelines 26-6Disabling the SNMP Agent 26-7Configuring Community Strings 26-7Configuring SNMP Groups and Users 26-9Configuring SNMP Notifications 26-11Setting the Agent Contact and Location Information 26-14Limiting TFTP Servers Used Through SNMP 26-14SNMP Examples 26-15

Displaying SNMP Status 26-16

C H A P T E R 27 Configuring Network Security with ACLs 27-1

Understanding ACLs 27-1Supported ACLs 27-2

Router ACLs 27-3Port ACLs 27-4VLAN Maps 27-4

Handling Fragmented and Unfragmented Traffic 27-5

Configuring IP ACLs 27-6Hardware and Software Handling of Router ACLs 27-6Unsupported Features 27-7Creating Standard and Extended IP ACLs 27-8

Access List Numbers 27-8Creating a Numbered Standard ACL 27-9Creating a Numbered Extended ACL 27-11Creating Named Standard and Extended IP ACLs 27-15Using Time Ranges with ACLs 27-17Including Comments in ACLs 27-19

Applying an IP ACL to an Interface or Terminal Line 27-19xxCatalyst 3550 Multilayer Switch Software Configuration Guide

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IP ACL Configuration Examples 27-21

Contents

Numbered ACLs 27-23Extended ACLs 27-23Named ACLs 27-23Time Range Applied to an IP ACL 27-24Commented IP ACL Entries 27-24ACL Logging 27-25

Configuring Named MAC Extended ACLs 27-26Applying a MAC ACL to a Layer 2 Interface 27-28

Configuring VLAN Maps 27-29VLAN Map Configuration Guidelines 27-30Creating a VLAN Map 27-30

Examples of ACLs and VLAN Maps 27-31Applying a VLAN Map to a VLAN 27-33Using VLAN Maps in Your Network 27-33

Wiring Closet Configuration 27-33Denying Access to a Server on Another VLAN 27-35

Using VLAN Maps with Router ACLs 27-36Guidelines for Using Router ACLs and VLAN Maps 27-36Examples of Router ACLs and VLAN Maps Applied to VLANs 27-37

ACLs and Switched Packets 27-37ACLs and Bridged Packets 27-38ACLs and Routed Packets 27-39ACLs and Multicast Packets 27-40

Displaying ACL Information 27-41Displaying ACL Configuration 27-41Displaying ACL Resource Usage and Configuration Problems 27-43

Configuration Conflicts 27-44ACL Configuration Fitting in Hardware 27-45TCAM Usage 27-47

C H A P T E R 28 Configuring QoS 28-1

Understanding QoS 28-2Basic QoS Model 28-4Classification 28-5

Classification Based on QoS ACLs 28-7Classification Based on Class Maps and Policy Maps 28-7

Policing and Marking 28-8Mapping Tables 28-10xxiCatalyst 3550 Multilayer Switch Software Configuration Guide

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Queueing and Scheduling 28-11

Contents

Queueing and Scheduling on Gigabit-Capable Ports 28-11Queueing and Scheduling on 10/100 Ethernet Ports 28-15

Packet Modification 28-17

Configuring Auto-QoS 28-17Generated Auto-QoS Configuration 28-18Effects of Auto-QoS on the Configuration 28-20Configuration Guidelines 28-20Enabling Auto-QoS for VoIP 28-21

Displaying Auto-QoS Information 28-22

Auto-QoS Configuration Example 28-23

Configuring Standard QoS 28-24Default Standard QoS Configuration 28-25Standard QoS Configuration Guidelines 28-26Enabling QoS Globally 28-28Configuring Classification By Using Port Trust States 28-29

Configuring the Trust State on Ports within the QoS Domain 28-29Configuring the CoS Value for an Interface 28-31Configuring a Trusted Boundary to Ensure Port Security 28-32Enabling Pass-Through Mode 28-33Configuring the DSCP Trust State on a Port Bordering Another QoS Domain 28-34

Configuring a QoS Policy 28-35Classifying Traffic by Using ACLs 28-36Classifying Traffic on a Physical-Port Basis by Using Class Maps 28-39Classifying Traffic on a Per-Port Per-VLAN Basis by Using Class Maps 28-41Classifying, Policing, and Marking Traffic by Using Policy Maps 28-43Classifying, Policing, and Marking Traffic by Using Aggregate Policers 28-49

Configuring DSCP Maps 28-51Configuring the CoS-to-DSCP Map 28-52Configuring the IP-Precedence-to-DSCP Map 28-52Configuring the Policed-DSCP Map 28-53Configuring the DSCP-to-CoS Map 28-54Configuring the DSCP-to-DSCP-Mutation Map 28-55

Configuring Egress Queues on Gigabit-Capable Ethernet Ports 28-57Mapping CoS Values to Select Egress Queues 28-57Configuring the Egress Queue Size Ratios 28-58Configuring Tail-Drop Threshold Percentages 28-59Configuring WRED Drop Thresholds Percentages 28-61Configuring the Egress Expedite Queue 28-62xxiiCatalyst 3550 Multilayer Switch Software Configuration Guide

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Allocating Bandwidth among Egress Queues 28-63

Contents

Configuring Egress Queues on 10/100 Ethernet Ports 28-64Mapping CoS Values to Select Egress Queues 28-64Configuring the Minimum-Reserve Levels 28-65Configuring the Egress Expedite Queue 28-66Allocating Bandwidth among Egress Queues 28-67

Displaying Standard QoS Information 28-69

Standard QoS Configuration Examples 28-69QoS Configuration for the Existing Wiring Closet 28-70QoS Configuration for the Intelligent Wiring Closet 28-71QoS Configuration for the Distribution Layer 28-72

C H A P T E R 29 Configuring EtherChannels 29-1

Understanding EtherChannels 29-1Understanding Port-Channel Interfaces 29-2Understanding the Port Aggregation Protocol and Link Aggregation Protocol 29-3

PAgP and LACP Modes 29-4Physical Learners and Aggregate-Port Learners 29-5PAgP and LACP Interaction with Other Features 29-6

Understanding Load Balancing and Forwarding Methods 29-6

Configuring EtherChannels 29-7Default EtherChannel Configuration 29-8EtherChannel Configuration Guidelines 29-8Configuring Layer 2 EtherChannels 29-9Configuring Layer 3 EtherChannels 29-11

Creating Port-Channel Logical Interfaces 29-11Configuring the Physical Interfaces 29-12

Configuring EtherChannel Load Balancing 29-14Configuring the PAgP Learn Method and Priority 29-15Configuring the LACP Port Priority 29-16Configuring Hot Standby Ports 29-16Configuring the LACP System Priority 29-17

Displaying EtherChannel, PAgP, and LACP Status 29-18

C H A P T E R 30 Configuring IP Unicast Routing 30-1

Understanding Routing 30-2

Steps for Configuring Routing 30-3

Configuring IP Addressing on Layer 3 Interfaces 30-4Default Addressing Configuration 30-4xxiiiCatalyst 3550 Multilayer Switch Software Configuration Guide

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Assigning IP Addresses to Network Interfaces 30-5

Contents

Use of Subnet Zero 30-6Classless Routing 30-7

Configuring Address Resolution Methods 30-8Define a Static ARP Cache 30-9Set ARP Encapsulation 30-10Enable Proxy ARP 30-10

Routing Assistance When IP Routing is Disabled 30-11Proxy ARP 30-11Default Gateway 30-11ICMP Router Discovery Protocol (IRDP) 30-12

Configuring Broadcast Packet Handling 30-13Enabling Directed Broadcast-to-Physical Broadcast Translation 30-13Forwarding UDP Broadcast Packets and Protocols 30-14Establishing an IP Broadcast Address 30-15Flooding IP Broadcasts 30-16

Monitoring and Maintaining IP Addressing 30-17

Enabling IP Unicast Routing 30-18

Configuring RIP 30-19Default RIP Configuration 30-19Configuring Basic RIP Parameters 30-20Configuring RIP Authentication 30-22Configuring Summary Addresses and Split Horizon 30-22

Configuring IGRP 30-24Default IGRP Configuration 30-25Understanding Load Balancing and Traffic Distribution Control 30-25Configuring Basic IGRP Parameters 30-26Configuring Split Horizon 30-28

Configuring OSPF 30-29Default OSPF Configuration 30-30Configuring Basic OSPF Parameters 30-31Configuring OSPF Interfaces 30-32Configuring OSPF Area Parameters 30-33Configuring Other OSPF Parameters 30-34Changing LSA Group Pacing 30-36Configuring a Loopback Interface 30-36Monitoring OSPF 30-37

Configuring EIGRP 30-38Default EIGRP Configuration 30-39xxivCatalyst 3550 Multilayer Switch Software Configuration Guide

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Configuring Basic EIGRP Parameters 30-40

Contents

Configuring EIGRP Interfaces 30-41Configuring EIGRP Route Authentication 30-42Monitoring and Maintaining EIGRP 30-43

Configuring BGP 30-44Default BGP Configuration 30-46Enabling BGP Routing 30-48Managing Routing Policy Changes 30-50Configuring BGP Decision Attributes 30-51Configuring BGP Filtering with Route Maps 30-53Configuring BGP Filtering by Neighbor 30-54Configuring Prefix Lists for BGP Filtering 30-55Configuring BGP Community Filtering 30-56Configuring BGP Neighbors and Peer Groups 30-58Configuring Aggregate Addresses 30-60Configuring a Routing Domain Confederation 30-60Configuring BGP Route Reflectors 30-61Configuring Route Dampening 30-62Monitoring and Maintaining BGP 30-63

Configuring Multi-VRF CE 30-65Understanding Multi-VRF CE 30-65Default Multi-VRF CE Configuration 30-67Multi-VRF CE Configuration Guidelines 30-68Configuring VRFs 30-69Configuring a VPN Routing Session 30-70Configuring BGP PE to CE Routing Sessions 30-70Multi-VRF CE Configuration Example 30-71Displaying Multi-VRF CE Status 30-75

Configuring Protocol-Independent Features 30-75Configuring Cisco Express Forwarding 30-75Configuring the Number of Equal-Cost Routing Paths 30-76Configuring Static Unicast Routes 30-77Specifying Default Routes and Networks 30-78Using Route Maps to Redistribute Routing Information 30-79Configuring Policy-Based Routing 30-82

PBR Configuration Guidelines 30-83Enabling PBR 30-84

Filtering Routing Information 30-85Setting Passive Interfaces 30-85Controlling Advertising and Processing in Routing Updates 30-86xxvCatalyst 3550 Multilayer Switch Software Configuration Guide

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Contents

Filtering Sources of Routing Information 30-87Managing Authentication Keys 30-88

Monitoring and Maintaining the IP Network 30-89

C H A P T E R 31 Configuring HSRP 31-1

Understanding HSRP 31-1

Configuring HSRP 31-3Default HSRP Configuration 31-4Enabling HSRP 31-4Configuring HSRP Group Attributes 31-6

Configuring HSRP Priority 31-6Configuring HSRP Authentication and Timers 31-8

Configuring HSRP Groups and Clustering 31-9

Displaying HSRP Configurations 31-10

C H A P T E R 32 Configuring Web Cache Services By Using WCCP 32-1

Understanding WCCP 32-2WCCP Message Exchange 32-3WCCP Negotiation 32-3MD5 Security 32-4Packet Redirection 32-4Unsupported WCCPv2 Features 32-4

Configuring WCCP 32-5Default WCCP Configuration 32-5WCCP Configuration Guidelines 32-5Enabling the Web Cache Service, Setting the Password, and Redirecting Traffic Received From a Client 32-6

Monitoring and Maintaining WCCP 32-9

C H A P T E R 33 Configuring IP Multicast Routing 33-1

Cisco Implementation of IP Multicast Routing 33-2Understanding IGMP 33-3

IGMP Version 1 33-3IGMP Version 2 33-4

Understanding PIM 33-5PIM Versions 33-5PIM Modes 33-5Auto-RP 33-8xxviCatalyst 3550 Multilayer Switch Software Configuration Guide

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Bootstrap Router 33-8

Contents

Multicast Forwarding and Reverse Path Check 33-9Neighbor Discovery 33-10

Understanding DVMRP 33-11DVMRP Neighbor Discovery 33-11DVMRP Route Table 33-11DVMRP Source Distribution Tree 33-11

Understanding CGMP 33-11Joining a Group with CGMP 33-12Leaving a Group with CGMP 33-13

Configuring IP Multicast Routing 33-13Default Multicast Routing Configuration 33-13Multicast Routing Configuration Guidelines 33-14

PIMv1 and PIMv2 Interoperability 33-14Auto-RP and BSR Configuration Guidelines 33-15

Configuring Basic Multicast Routing 33-15Configuring a Rendezvous Point 33-17

Manually Assigning an RP to Multicast Groups 33-17Configuring Auto-RP 33-18Configuring PIMv2 BSR 33-22

Using Auto-RP and a BSR 33-27Monitoring the RP Mapping Information 33-27Troubleshooting PIMv1 and PIMv2 Interoperability Problems 33-28

Configuring Advanced PIM Features 33-28Understanding PIM Shared Tree and Source Tree 33-28Delaying the Use of PIM Shortest-Path Tree 33-29Modifying the PIM Router-Query Message Interval 33-30

Configuring Optional IGMP Features 33-31Default IGMP Configuration 33-31Changing the IGMP Version 33-32Changing the IGMP Query Timeout for IGMPv2 33-32Changing the Maximum Query Response Time for IGMPv2 33-33Configuring the Multilayer Switch as a Member of a Group 33-34Controlling Access to IP Multicast Groups 33-35Modifying the IGMP Host-Query Message Interval 33-36Configuring the Multilayer Switch as a Statically Connected Member 33-36

Configuring Optional Multicast Routing Features 33-37Enabling CGMP Server Support 33-38Configuring sdr Listener Support 33-39xxviiCatalyst 3550 Multilayer Switch Software Configuration Guide

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Enabling sdr Listener Support 33-39

Contents

Limiting How Long an sdr Cache Entry Exists 33-39Configuring the TTL Threshold 33-40Configuring an IP Multicast Boundary 33-42

Configuring Basic DVMRP Interoperability Features 33-43Configuring DVMRP Interoperability 33-44Controlling Unicast Route Advertisements 33-44Configuring a DVMRP Tunnel 33-46Advertising Network 0.0.0.0 to DVMRP Neighbors 33-48Responding to mrinfo Requests 33-49

Configuring Advanced DVMRP Interoperability Features 33-50Enabling DVMRP Unicast Routing 33-50Rejecting a DVMRP Nonpruning Neighbor 33-51Controlling Route Exchanges 33-53

Limiting the Number of DVMRP Routes Advertised 33-53Changing the DVMRP Route Threshold 33-54Configuring a DVMRP Summary Address 33-54Disabling DVMRP Autosummarization 33-56Adding a Metric Offset to the DVMRP Route 33-56

Monitoring and Maintaining IP Multicast Routing 33-57Clearing Caches, Tables, and Databases 33-58Displaying System and Network Statistics 33-58Monitoring IP Multicast Routing 33-59

C H A P T E R 34 Configuring MSDP 34-1

Understanding MSDP 34-1MSDP Operation 34-2MSDP Benefits 34-3

Configuring MSDP 34-4Default MSDP Configuration 34-4Configuring a Default MSDP Peer 34-4Caching Source-Active State 34-6Requesting Source Information from an MSDP Peer 34-8Controlling Source Information that Your Switch Originates 34-8

Redistributing Sources 34-9Filtering Source-Active Request Messages 34-11

Controlling Source Information that Your Switch Forwards 34-12Using a Filter 34-12Using TTL to Limit the Multicast Data Sent in SA Messages 34-14xxviiiCatalyst 3550 Multilayer Switch Software Configuration Guide

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Controlling Source Information that Your Switch Receives 34-14

Contents

Configuring an MSDP Mesh Group 34-16Shutting Down an MSDP Peer 34-16Including a Bordering PIM Dense-Mode Region in MSDP 34-17Configuring an Originating Address other than the RP Address 34-18

Monitoring and Maintaining MSDP 34-19

C H A P T E R 35 Configuring Fallback Bridging 35-1

Understanding Fallback Bridging 35-1

Configuring Fallback Bridging 35-3Default Fallback Bridging Configuration 35-3Fallback Bridging Configuration Guidelines 35-3Creating a Bridge Group 35-4Preventing the Forwarding of Dynamically Learned Stations 35-5Configuring the Bridge Table Aging Time 35-6Filtering Frames by a Specific MAC Address 35-6Adjusting Spanning-Tree Parameters 35-7

Changing the Switch Priority 35-8Changing the Interface Priority 35-8Assigning a Path Cost 35-9Adjusting BPDU Intervals 35-10Disabling the Spanning Tree on an Interface 35-12

Monitoring and Maintaining Fallback Bridging 35-12

C H A P T E R 36 Troubleshooting 36-1

Using Recovery Procedures 36-1Recovering from Corrupted Software 36-2Recovering from a Lost or Forgotten Password 36-2

Password Recovery with Password Recovery Enabled 36-3Procedure with Password Recovery Disabled 36-5

Recovering from a Command Switch Failure 36-6Replacing a Failed Command Switch with a Cluster Member 36-7Replacing a Failed Command Switch with Another Switch 36-8

Recovering from Lost Member Connectivity 36-10

Preventing Autonegotiation Mismatches 36-10

GBIC Module Security and Identification 36-10

Diagnosing Connectivity Problems 36-11Using Ping 36-11

Understanding Ping 36-11xxixCatalyst 3550 Multilayer Switch Software Configuration Guide

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Executing Ping 36-11

Contents

Using IP Traceroute 36-12Understanding IP Traceroute 36-13Executing IP Traceroute 36-13

Using Layer 2 Traceroute 36-14Understanding Layer 2 Traceroute 36-15Switches Supporting Layer 2 Traceroute 36-15Usage Guidelines 36-15Displaying the Physical Path 36-16

Using Debug Commands 36-16Enabling Debugging on a Specific Feature 36-17Enabling All-System Diagnostics 36-17Redirecting Debug and Error Message Output 36-18Using the debug autoqos Command 36-18

Using the show forward Command 36-19

Using the crashinfo File 36-20

A P P E N D I X A Supported MIBs A-1

MIB List A-1

Using FTP to Access the MIB Files A-3

A P P E N D I X B Working with the IOS File System, Configuration Files, and Software Images B-1

Working with the Flash File System B-1Displaying Available File Systems B-2Setting the Default File System B-3Displaying Information about Files on a File System B-3Changing Directories and Displaying the Working Directory B-3Creating and Removing Directories B-4Copying Files B-4Deleting Files B-5Creating, Displaying, and Extracting tar Files B-6

Creating a tar File B-6Displaying the Contents of a tar File B-6Extracting a tar File B-7

Displaying the Contents of a File B-8

Working with Configuration Files B-8Guidelines for Creating and Using Configuration Files B-9Configuration File Types and Location B-9Creating a Configuration File By Using a Text Editor B-10xxxCatalyst 3550 Multilayer Switch Software Configuration Guide

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Copying Configuration Files By Using TFTP B-10

Contents

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

Copying Configuration Files By Using FTP B-12Preparing to Download or Upload a Configuration File By Using FTP B-13Downloading a Configuration File By Using FTP B-13Uploading a Configuration File By Using FTP B-15

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

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

Working with Software Images B-19Image Location on the Switch B-20tar File Format of Images on a Server or Cisco.com B-20Copying Image Files By Using TFTP B-21

Preparing to Download or Upload an Image File By Using TFTP B-21Downloading an Image File By Using TFTP B-22Uploading an Image File By Using TFTP B-24

Copying Image Files By Using FTP B-24Preparing to Download or Upload an Image File By Using FTP B-25Downloading an Image File By Using FTP B-26Uploading an Image File By Using FTP B-28

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

A P P E N D I X C Unsupported CLI Commands in Release 12.1(13)EA1 C-1

Access Control Lists C-1Unsupported Privileged EXEC Commands C-1

ARP Commands C-1Unsupported Global Configuration Commands C-1Unsupported Interface Configuration Commands C-1

FallBack Bridging C-2Unsupported Privileged EXEC Commands C-2xxxiCatalyst 3550 Multilayer Switch Software Configuration Guide

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Unsupported Global Configuration Commands C-2

Contents

Unsupported Interface Configuration Commands C-2

HSRP C-3Unsupported Global Configuration Commands C-3Unsupported Interface Configuration Commands C-3

Interface Configuration Commands C-4

IP Multicast Routing C-4Unsupported Privileged EXEC Commands C-4Unsupported Global Configuration Commands C-4Unsupported Interface Configuration Commands C-5

IP Unicast Routing C-5Unsupported Privileged EXEC or User EXEC Commands C-5Unsupported Global Configuration Commands C-6Unsupported Interface Configuration Commands C-6Unsupported BGP Router Configuration Commands C-6Unsupported VPN Configuration Commands C-7Unsupported Route Map Commands C-7

MSDP C-7Unsupported Privileged EXEC Commands C-7Unsupported Global Configuration Commands C-8

RADIUS C-8Unsupported Global Configuration Commands C-8

SNMP C-8Unsupported Global Configuration Commands C-8

Spanning Tree C-8Unsupported Global Configuration Commands C-8

VLAN C-8Unsupported User EXEC Commands C-8

IN D E XxxxiiCatalyst 3550 Multilayer Switch Software Configuration Guide

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Preface

AudienceThis guide is for the networking professional managing the Catalyst 3550 switch, hereafter referred to as the switch or the multilayer switch. Before using this guide, you should have experience working with the Cisco IOS and be familiar with the concepts and terminology of Ethernet and local area networking.

PurposeThis guide provides the information you need to configure Layer 2 and Layer 3 software features on your switch. The Catalyst 3550 switch is supported by either the standard multilayer software image (SMI), which provides Layer 2+ features and basic Layer 3 routing, or the enhanced multilayer software image (EMI), which provides Layer 2+ features, full Layer 3 routing, and advanced services. All Catalyst 3550 Gigabit Ethernet switches are shipped with the EMI pre-installed. Catalyst 3550 Fast Ethernet switches are shipped with either the SMI or the EMI pre-installed. After initial deployment, you can order the Enhanced Multilayer Software Image Upgrade kit to upgrade Catalyst 3550 Fast Ethernet switches from the SMI to the EMI.This guide provides procedures for using the commands that have been created or changed for use with the Catalyst 3550 switch. It does not provide detailed information about these commands. For detailed information about these commands, refer to the Catalyst 3550 Multilayer Switch Command Reference for this release. For information about the standard IOS Release 12.1 commands, refer to the IOS documentation set available from the Cisco.com 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 also includes an overview of the Cluster Management Suite (CMS) web-based, switch management interface, which helps you create and manage clusters of switches. This guide does not provide field-level descriptions of the CMS windows nor does it provide the procedures for configuring switches and switch clusters from CMS. For all CMS window descriptions and procedures, refer to the CMS online help, which is integrated with the software image.xxxiiiCatalyst 3550 Multilayer Switch Software Configuration Guide

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This guide does not describe system messages you might encounter or how to install your switch. For more information, refer to the Catalyst 3550 Multilayer Switch System Message Guide for this release and to the Catalyst 3550 Multilayer Switch Hardware Installation Guide.

PrefaceConventionsConventionsThis publication uses these conventions to convey instructions and information:Command descriptions use these conventions:

Commands and keywords are in boldface text. Arguments for which you supply values are in italic. Square brackets ([ ]) mean optional elements. Braces ({ }) group required choices, and vertical bars ( | ) separate the alternative elements. Braces and vertical bars within square brackets ([{ | }]) mean a required choice within an optional

element.

Interactive examples use these conventions: Terminal sessions and system displays are in screen font. Information you enter is in boldface screen font.

Nonprinting characters, such as passwords or tabs, are in angle brackets (< >).Notes, cautions, and timesavers use these conventions and symbols:

Note 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 equipment damage or loss of data.

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

http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/index.htmYou can order printed copies of documents with a DOC-xxxxxx= number from the Cisco.com sites and from the telephone numbers listed in the Ordering Documentation section on page xxxv.

Release Notes for the Catalyst 3550 Multilayer Switch (not orderable but available on Cisco.com)

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 Cisco.com for the latest information.xxxivCatalyst 3550 Multilayer Switch Software Configuration Guide

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PrefaceObtaining Documentation Catalyst 3550 Multilayer Switch Software Configuration Guide (order number DOC-7811194=) Catalyst 3550 Multilayer Switch Command Reference (order number DOC-7811195=) Catalyst 3550 Multilayer Switch System Message Guide (order number DOC-7811196=) Cluster Management Suite (CMS) online help (available only from the switch CMS software) Catalyst 3550 Multilayer Switch Hardware Installation Guide (order number DOC-7811358=) 1000BASE-T Gigabit Interface Converter Installation Note (not orderable but is available on

Cisco.com) Catalyst GigaStack Gigabit Interface Converter Hardware Installation Guide

(order number DOC-786460=)

Obtaining DocumentationCisco provides several ways to obtain documentation, technical assistance, and other technical resources. These sections explain how to obtain technical information from Cisco Systems.

Cisco.comYou can access the most current Cisco documentation on the World Wide Web at this URL:http://www.cisco.com/univercd/home/home.htmYou can access the Cisco website at this URL:http://www.cisco.comInternational Cisco web sites can be accessed from this URL:http://www.cisco.com/public/countries_languages.shtml

Documentation CD-ROMCisco documentation and additional literature are available in a Cisco Documentation CD-ROM package, which may have shipped with your product. The Documentation CD-ROM is updated monthly and may be more current than printed documentation. The CD-ROM package is available as a single unit or through an annual subscription.Registered Cisco.com users can order the Documentation CD-ROM (product number DOC-CONDOCCD=) through the online Subscription Store:http://www.cisco.com/go/subscription

Ordering DocumentationYou can find instructions for ordering documentation at this URL:http://www.cisco.com/univercd/cc/td/doc/es_inpck/pdi.htmYou can order Cisco documentation in these ways:

Registered Cisco.com users (Cisco direct customers) can order Cisco product documentation from the Networking Products MarketPlace:xxxvCatalyst 3550 Multilayer Switch Software Configuration Guide

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PrefaceObtaining Technical Assistancehttp://www.cisco.com/en/US/partner/ordering/index.shtml Registered Cisco.com users can order the Documentation CD-ROM (Customer Order Number

DOC-CONDOCCD=) through the online Subscription Store:http://www.cisco.com/go/subscription

Nonregistered Cisco.com users can order documentation through a local account representative by calling Cisco Systems Corporate Headquarters (California, U.S.A.) at 408 526-7208 or, elsewhere in North America, by calling 800 553-NETS (6387).

Documentation FeedbackYou can submit comments electronically on Cisco.com. On the Cisco Documentation home page, click Feedback at the top of the page.You can email your comments to bug-doc@cisco.com.You can submit your comments by mail by using the response card behind the front cover of your document or by writing to the following address:Cisco SystemsAttn: Customer Document Ordering170 West Tasman DriveSan Jose, CA 95134-9883We appreciate your comments.

Obtaining Technical AssistanceCisco provides Cisco.com, which includes the Cisco Technical Assistance Center (TAC) Website, as a starting point for all technical assistance. Customers and partners can obtain online documentation, troubleshooting tips, and sample configurations from the Cisco TAC website. Cisco.com registered users have complete access to the technical support resources on the Cisco TAC website, including TAC tools and utilities.

Cisco.comCisco.com offers a suite of interactive, networked services that let you access Cisco information, networking solutions, services, programs, and resources at any time, from anywhere in the world. Cisco.com provides a broad range of features and services to help you with these tasks:

Streamline business processes and improve productivity Resolve technical issues with online support

Download and test software packages Order Cisco learning materials and merchandise Register for online skill assessment, training, and certification programs

To obtain customized information and service, you can self-register on Cisco.com at this URL:http://www.cisco.comxxxviCatalyst 3550 Multilayer Switch Software Configuration Guide

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PrefaceObtaining Technical AssistanceTechnical Assistance CenterThe Cisco TAC is available to all customers who need technical assistance with a Cisco product, technology, or solution. Two levels of support are available: the Cisco TAC website and the Cisco TAC Escalation Center. The avenue of support that you choose depends on the priority of the problem and the conditions stated in service contracts, when applicable.We categorize Cisco TAC inquiries according to urgency:

Priority level 4 (P4)You need information or assistance concerning Cisco product capabilities, product installation, or basic product configuration.

Priority level 3 (P3)Your network performance is degraded. Network functionality is noticeably impaired, but most business operations continue.

Priority level 2 (P2)Your production network is severely degraded, affecting significant aspects of business operations. No workaround is available.

Priority level 1 (P1)Your production network is down, and a critical impact to business operations will occur if service is not restored quickly. No workaround is available.

Cisco TAC Website

You can use the Cisco TAC website to resolve P3 and P4 issues yourself, saving both cost and time. The site provides around-the-clock access to online tools, knowledge bases, and software. To access the Cisco TAC website, go to this URL:http://www.cisco.com/tacAll customers, partners, and resellers who have a valid Cisco service contract have complete access to the technical support resources on the Cisco TAC website. Some services on the Cisco TAC website require a Cisco.com login ID and password. If you have a valid service contract but do not have a login ID or password, go to this URL to register:http://tools.cisco.com/RPF/register/register.doIf you are a Cisco.com registered user, and you cannot resolve your technical issues by using the Cisco TAC website, you can open a case online at this URL:http://www.cisco.com/en/US/support/index.htmlIf you have Internet access, we recommend that you open P3 and P4 cases through the Cisco TAC website so that you can describe the situation in your own words and attach any necessary files.

Cisco TAC Escalation Center

The Cisco TAC Escalation Center addresses priority level 1 or priority level 2 issues. These classifications are assigned when severe network degradation significantly impacts business operations. When you contact the TAC Escalation Center with a P1 or P2 problem, a Cisco TAC engineer automatically opens a case.

To obtain a directory of toll-free Cisco TAC telephone numbers for your country, go to this URL:http://www.cisco.com/warp/public/687/Directory/DirTAC.shtmlBefore calling, please check with your network operations center to determine the level of Cisco support services to which your company is entitled: for example, SMARTnet, SMARTnet Onsite, or Network Supported Accounts (NSA). When you call the center, please have available your service agreement number and your product serial number.xxxviiCatalyst 3550 Multilayer Switch Software Configuration Guide

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PrefaceObtaining Additional Publications and InformationObtaining Additional Publications and InformationInformation about Cisco products, technologies, and network solutions is available from various online and printed sources.

The Cisco Product Catalog describes the networking products offered by Cisco Systems as well as ordering and customer support services. Access the Cisco Product Catalog at this URL:http://www.cisco.com/en/US/products/products_catalog_links_launch.html

Cisco Press publishes a wide range of networking publications. Cisco suggests these titles for new and experienced users: Internetworking Terms and Acronyms Dictionary, Internetworking Technology Handbook, Internetworking Troubleshooting Guide, and the Internetworking Design Guide. For current Cisco Press titles and other information, go to Cisco Press online at this URL:http://www.ciscopress.com

Packet magazine is the Cisco monthly periodical that provides industry professionals with the latest information about the field of networking. You can access Packet magazine at this URL:http://www.cisco.com/en/US/about/ac123/ac114/about_cisco_packet_magazine.html

iQ Magazine is the Cisco monthly periodical that provides business leaders and decision makers with the latest information about the networking industry. You can access iQ Magazine at this URL:http://business.cisco.com/prod/tree.taf%3fasset_id=44699&public_view=true&kbns=1.html

Internet Protocol Journal is a quarterly journal published by Cisco Systems for engineering professionals involved in the design, development, and operation of public and private internets and intranets. You can access the Internet Protocol Journal at this URL:http://www.cisco.com/en/US/about/ac123/ac147/about_cisco_the_internet_protocol_journal.html

TrainingCisco offers world-class networking training, with current offerings in network training listed at this URL:http://www.cisco.com/en/US/learning/le31/learning_recommended_training_list.htmlxxxviiiCatalyst 3550 Multilayer Switch Software Configuration Guide

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be managed through a single IP address. Extended discovery of cluster candidates that are no

See the Advantages of Using CMS and Clustering Swcluster hardware, software, and browser requirements,t directly connected to the command switch.itches section on page 1-7. For the CMS, refer to the release notes.C H A P T E R

1Overview

This chapter provides these topics about the Catalyst 3550 multilayer switch software: Features, page 1-1

Management Options, page 1-7 Network Configuration Examples, page 1-8 Where to Go Next, page 1-18

FeaturesThe Catalyst 3550 software supports the hardware listed in the release notes. This section describes the features supported in this release:

Note All Catalyst 3550 Gigabit Ethernet switches ship with the enhanced multilayer software image (EMI), which provides Layer 2+ features, full Layer 3 routing, and advanced services. Catalyst 3550 Fast Ethernet switches can be shipped with either the standard multilayer software image (SMI) or EMI installed. The SMI software image provides Layer 2+ features and basic Layer 3 routing. You can order the Enhanced Multilayer Software Image Upgrade kit to upgrade Catalyst 3550 Fast Ethernet switches from the SMI to the EMI.

Ease of Use and Ease of Deployment Cluster Management Suite (CMS) software for simplifying switch and switch cluster management

through a web browser, such as Netscape Communicator or Microsoft Internet Explorer, from anywhere in your intranet

Switch clustering technology used with CMS, for Unified configuration, monitoring, authentication, and software upgrade of multiple switches

(refer to the release notes for a list of eligible cluster members). Automatic discovery of candidate switches and creation of clusters of up to 16 switches that can 1-1r Switch Software Configuration Guide

Chapter 1 OverviewFeaturesPerformance Autosensing of port speed and autonegotiation of duplex mode on all switch ports for optimizing

bandwidth IEEE 802.3X flow control on all Ethernet ports EtherChannel for enhanced fault tolerance and for providing up to 8 Gbps (Gigabit EtherChannel)

or 800 Mbps (Fast EtherChannel) full duplex of bandwidth between switches, routers, and servers Port Aggregation Protocol (PAgP) and Link Aggregation Control Protocol (LACP) for automatic

creation of EtherChannel links Per-port storm control for preventing broadcast, multicast, and unicast storms Port blocking on forwarding unknown unicast and multicast traffic Cisco Group Management Protocol (CGMP) server support and Internet Group Management

Protocol (IGMP) snooping for IGMP versions 1 and 2: (For CGMP devices) CGMP for limiting multicast traffic to specified end stations and reducing

overall network traffic

(For IGMP devices) IGMP snooping for limiting flooding of multicast traffic Multicast VLAN registration (MVR) to continuously send multicast streams in a multicast VLAN

while isolating the streams from subscriber VLANs for bandwidth and security reasons IGMP filtering for controlling the set of multicast groups to which hosts on a switch port can belong System Database Management (SDM) templates for allocating system resources to maximize

support for user-selected features Web Cache Communication Protocol (WCCP) for redirecting traffic to local cache engines, for

enabling content requests to be fulfilled locally, and for localizing web-traffic patterns in the network (requires the enhanced multilayer software image)

Manageability Cisco Intelligence Engine 2100 (IE2100) Series Cisco Networking Services (CNS) embedded

agents for automating switch management, configuration storage and delivery. Dynamic Host Configuration Protocol (DHCP) for automating configuration of switch information

(such as IP address, default gateway, host name, and Domain Name System [DNS] and Trivial File Transfer Protocol [TFTP] server names)

DHCP relay agent information (option 82) for subscriber identification and IP address management Directed unicast requests to a DNS server for identifying a switch through its IP address and its

corresponding host name 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 Media Access Control (MAC) address

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

Network Time Protocol (NTP) for providing a consistent timestamp to all switches from an external source

Cisco IOS File System (IFS) for providing a single interface to all file systems that the switch uses In-band management access through CMS In-band management access through up to 16 simultaneous Telnet connections for multiple

command-line interface (CLI)-based sessions over the network1-2Catalyst 3550 Multilayer Switch Software Configuration Guide

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Chapter 1 OverviewFeatures In-band management access for up to five simultaneous, encrypted Secure Shell (SSH) connections for multiple CLI-based sessions over the network

In-band management access through Simple Network Management Protocol (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

Note For additional descriptions of the management interfaces, see the Management Options section on page 1-7.

Redundancy Hot Standby Router Protocol (HSRP) for command switch and Layer 3 router redundancy UniDirectional Link Detection (UDLD) and aggressive UDLD on all Ethernet ports 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: Per-VLAN Spanning Tree (PVST) for balancing load across VLANs Per-VLAN Rapid Spanning Tree (PVRST) for balancing load across VLANs UplinkFast, cross-stack UplinkFast, and BackboneFast for fast convergence after a

spanning-tree topology change and for achieving load balancing between redundant uplinks, including Gigabit uplinks and cross-stack Gigabit uplinks

IEEE 802.1S Multiple Spanning Tree Protocol (MSTP) for grouping VLANs into a spanning-tree instance, and providing for multiple forwarding paths for data traffic and load balancing

IEEE 802.1W Rapid Spanning Tree Protocol (RSTP) for rapid convergence of the spanning tree by immediately transitioning root and designated ports to the forwarding state

Optional spanning-tree features available in PVST, PVRST, and MSTP mode: Port Fast for eliminating the forwarding delay by enabling a port to immediately transition from

the blocking state to the forwarding state BPDU guard for shutting down Port Fast-enabled ports that receive 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

Note The switch supports up to 128 spanning-tree instances.

VLAN Support Support for up to 1005 VLANs for assigning users to VLANs associated with appropriate network

resources, traffic patterns, and bandwidth Support for VLAN IDs in the full 1 to 4094 range allowed by the IEEE 802.1Q standard VLAN Query Protocol (VQP) for dynamic VLAN membership1-3Catalyst 3550 Multilayer Switch Software Configuration Guide

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Chapter 1 OverviewFeatures Inter-Switch Link (ISL) and 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 (802.1Q or ISL) 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 PhonesSecurity

Password-protected access (read-only and read-write access) to management interfaces (CMS and CLI) for protection against unauthorized configuration changes

Multilevel security for a choice of security level, notification, and resulting actions Static MAC addressing for ensuring security Protected port option for restricting the forwarding of traffic to designated ports on the same switch Port security option for limiting and identifying MAC addresses of the stations allowed to access

the port Port security aging to set the aging time for secure addresses on a port Bridge protocol data unit (BPDU) guard for shutting down a Port Fast-configured port when an

invalid configuration occurs Standard and extended IP access control lists (ACLs) for defining security policies in both directions

on routed interfaces (router ACLs) and inbound on Layer 2 interfaces (port ACLs) Extended MAC access control lists for defining security policies in the inbound direction on Layer 2

interfaces

VLAN ACLs (VLAN maps) for providing intra-VLAN security by filtering traffic based on information in the MAC, IP, and TCP/User Datagram Protocol (UDP) headers

Source and destination MAC-based ACLs for filtering non-IP traffic IEEE 802.1X port-based authentication to prevent unauthorized devices (clients) from gaining

access to the network

802.1X with per-user access control lists for providing different levels of network access and service to an 802.1X-authenticated user

802.1X with VLAN assignment for restricting 802.1X-authenticated users to a specified VLAN 802.1X with port security for controlling access to 802.1X multiple-host ports 802.1X with voice VLAN to permit an IP phone access to the voice VLAN irrespective of the

authorized or unauthorized state of the port Terminal Access Controller Access Control System Plus (TACACS+), a proprietary feature for

managing network security through a TACACS server Kerberos security system to authenticate requests for network resources by using a trusted third

party

Remote Authentication Dial-In User Service (RADIUS), which provides detailed accounting information and flexible administrative control over authentication and authorization processes

802.1Q tunneling to allow customers with users at remote sites across a service provider network to keep VLANs segregated from other customers and Layer 2 protocol tunneling to ensure that the customers network has complete STP, CDP, and VTP information about all users1-4Catalyst 3550 Multilayer Switch Software Configuration Guide

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Chapter 1 OverviewFeaturesQuality of Service (QoS) and Class of Service (CoS) Automatic QoS (auto-QoS) to simplify the deployment of existing QoS features by classifying

traffic and configuring egress queues (voice over IP only) Classification

Classification on a physical interface or on a per-port per-VLAN basis IP type-of-service/Differentiated Services Code Point (IP TOS/DSCP) and 802.1P CoS marking

priorities on a per-port basis for protecting the performance of mission-critical applications IP TOS/DSCP and 802.1P CoS marking based on flow-based packet classification

(classification based on information in the MAC, IP, and TCP/UDP headers) for high-performance quality of service at the network edge, allowing for differentiated service levels for different types of network traffic and for prioritizing mission-critical traffic in the network

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

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

Policing

Policing on a physical interface or on a per-port per-VLAN basis Traffic-policing policies on the switch port for managing how much of the port bandwidth

should be allocated to a specific traffic flow Aggregate policing for policing traffic flows in aggregate to restrict specific applications or

traffic flows to metered, predefined rates Up to 128 policers on ingress Gigabit-capable Ethernet ports

Up to eight policers on ingress 10/100 portsUp to eight policers per egress port (aggregate policers only)

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

Egress Policing and Scheduling of Egress Queues Four egress queues on all switch ports. These queues can either be configured with the Weighted

Round Robin (WRR) scheduling algorithm or configured with one queue as a strict priority queue and the other three queues for WRR. The strict priority queue must be empty before the other three queues are serviced. You can use the strict priority queue for mission-critical and time-sensitive traffic.

Tail drop and Weight Random Early Detection (WRED) techniques for avoiding congestion on Gigabit Ethernet ports; tail drop for congestion avoidance on Fast Ethernet ports

Layer 3 Support (Some features and protocols require the enhanced multilayer software image.) Hot Standby Router Protocol (HSRP) for Layer 3 router redundancy IP routing protocols for load balancing and for constructing scalable, routed backbones:

Routing Information Protocol (RIP) versions 1 and 2 Open Shortest Path First (OSPF) Interior Gateway Routing Protocol (IGRP) and Enhanced IGRP (EIGRP) Border Gateway Protocol (BGP) Version 4 1-5Catalyst 3550 Multilayer Switch Software Configuration Guide

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Chapter 1 OverviewFeatures IP routing between VLANs (inter-VLAN routing) for full Layer 3 routing between two or more VLANs, allowing each VLAN to maintain its own autonomous data-link domain

Multiple VPN routing/forwarding (multi-VRF) instances in customer edge (CE) devices to allow service providers to support multiple virtual private networks (VPNs) and overlap IP addresses between VPNs.

Policy-based routing (PBR) for configuring defined policies for traffic flows Fallback bridging for forwarding non-IP traffic between two or more VLANs Static IP routing for manually building a routing table of network path information Equal-cost routing for load balancing and redundancy Internet Control Message Protocol (ICMP) and ICMP Router Discovery Protocol (IRDP) for using

router advertisement and router solicitation messages to discover the addresses of routers on directly attached subnets

Protocol-Independent Multicast (PIM) for multicast routing within the network, allowing for devices in the network to receive the multicast feed requested and for switches not participating in the multicast to be pruned. Includes support for PIM sparse mode (PIM-SM), PIM dense mode (PIM-DM), and PIM sparse-dense mode.

Distance Vector Multicast Routing Protocol (DVMRP) tunnelling for interconnecting two multicast-enabled networks across non-multicast networks

DHCP relay for forwarding UDP broadcasts, including IP address requests, from DHCP clientsMonitoring

Switch LEDs that provide port- and switch-level status Switched Port Analyzer (SPAN) and Remote SPAN (RSPAN) for traffic monitoring on any port or

VLAN

SPAN and RSPAN support of Intrusion Detection Systems (IDSs) to monitor, repel, and report network security violations

Four groups (history, statistics, alarms, and events) of embedded remote monitoring (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

MAC address notification for tracking users on a network by storing the MAC addresses that the switch has learned or removed

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

Inline Power Support for the Catalyst 3550-24PWR Switch Ability to provide inline power to Cisco IP Phones and Cisco Aironet Access Points from all 24

10/100 Ethernet ports Autodetection and control of inline phone power on a per-port basis on all 10/100 ports Fan-fault and over-temperature detection through Cluster Management Suite (CMS)1-6Catalyst 3550 Multilayer Switch Software Configuration Guide

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Chapter 1 OverviewManagement OptionsManagement OptionsThe Catalyst 3550 switch is designed for plug-and-play operation: you need to configure only basic IP information for the switch and connect it to the other devices in your network. If you have specific network needs, you can configure and monitor the switchon an individual basis or as part of a switch clusterthrough its various management interfaces.

Management Interface OptionsYou can configure and monitor individual switches and switch clusters by using these interfaces:

CMSCMS is a graphical user interface that can be launched from anywhere in your network through a web browser such as Netscape Communicator or Microsoft Internet Explorer. CMS is already installed on the switch. Using CMS, you can configure and monitor a standalone switch, a specific cluster member, or an entire switch cluster. You can also display network topologies to gather link information and to display switch images to modify switch and port settings.For more information about CMS, see Chapter 3, Getting Started with CMS.

CLIThe switch IOS CLI software is enhanced to support desktop- and multilayer-switching features. You can configure and monitor the switch and switch cluster members from the CLI. You can access the CLI either by connecting your management station directly to the switch console port or by using Telnet from a remote management station.For more information about the CLI, see Chapter 2, Using the Command-Line Interface.

IE2100Cisco Intelligence Engine 2100 Series Configuration Registrar is a network management device that works with embedded CNS Agents in the switch software. 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 IE2100, see Chapter 5, Configuring IE2100 CNS Agents.

SNMPSNMP provides a means to monitor and control the switch and switch cluster members. You can manage switch configuration settings, performance, security, and collect statistics by using SNMP management applications such as CiscoWorks2000 LAN Management Suite (LMS) and HP OpenView. You can manage the switch 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 RMON groups.For more information about using SNMP, see Chapter 26, Configuring SNMP.

Advantages of Using CMS and Clustering SwitchesUsing CMS and switch clusters can simplify and minimize your configuration and monitoring tasks. You can use Cisco switch clustering technology to manage up to 16 interconnected, supported Catalyst switches through one IP address. This can conserve IP addresses if you have a limited number of them. CMS is the easiest interface to use and makes switch and switch cluster management accessible to authorized users from any PC on your network.1-7Catalyst 3550 Multilayer Switch Software Configuration Guide

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Chapter 1 OverviewNetwork Configuration ExamplesBy using switch clusters and CMS, you can Manage and monitor interconnected Catalyst switches (refer to the release notes for a list of

supported switches), regardless of their geographic proximity and interconnection media, including Ethernet, Fast Ethernet, Fast EtherChannel, Cisco GigaStack Gigabit Interface Converter (GBIC), Gigabit Ethernet, and Gigabit EtherChannel connections.

Accomplish multiple configuration tasks from a single CMS window without needing to remember CLI commands to accomplish specific tasks.

Apply actions from CMS to multiple ports and multiple switches at the same time. Here are some examples of configuring and managing multiple ports and switches: Port configuration such as speed and duplex settings Port and console port security settings NTP, STP, VLAN, and QoS configurations Inventory and statistic reporting and link- and switch-level monitoring and troubleshooting Group software upgrades

View a topology of interconnected devices to identify existing switch clusters and eligible switches that can join a cluster. You can also use the topology to quickly identify link information between switches.

Monitor 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.

Use an interactive mode that takes you step-by-step through configuring complex features such as VLANs, ACLs, and QoS.

Use a wizard that prompts you to provide only the minimum required information to configure complex features such as QoS priorities for video traffic, priority levels for data applications, and security.

For more information about CMS, see Chapter 3, Getting Started with CMS. For more information about switch clusters, see Chapter 6, Clustering Switches.

Network Configuration ExamplesThis 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 1-9 Small to Medium-Sized Network Using Mixed Switches section on page 1-12 Large Network Using Only Catalyst 3550 Switches section on page 1-14 Multidwelling Network Using Catalyst 3550 Switches section on page 1-15 Long-Distance, High-Bandwidth Transport Configuration section on page 1-171-8Catalyst 3550 Multilayer Switch Software Configuration Guide

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Chapter 1 OverviewNetwork Configuration ExamplesDesign Concepts for Using the SwitchAs your network users compete for network bandwidth, it takes longer to send and receive data. When you configure your network, consider the bandwidth required by your network users and the relative priority of the network applications they use.

Table 1-1 describes what can cause network performance to degrade and how you can configure your network to increase the bandwidth available to your network users.

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 those demands.

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

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. 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)

Connect global resourcessuch as servers and routers to which the