Cisco Catalyst 4500 Series Command Reference Guide

2-990
Catalyst 4500 Series Switch Cisco IOS Command Reference—Release IOS XE 3.4.0SG and IOS 15.1(2)SG)
OL-27596 -01
Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
spanning-tree extend system-id
spanning-tree extend system-id
To enable the extended system ID feature on a chassis that supports 1024 MAC addresses, use the
spanning-tree extend system-id command. To disable the feature, use the no form of this command.
spanning-tree extend system-id
no spanning-tree extend system-id
Syntax Description This command has no arguments or keywords.
Defaults Enabled on systems that do not provide 1024 MAC addresses.
Command Modes Global configuration mode
Command History
Usage Guidelines Releases 12.1(13)E and later support chassis with 64 or 1024 MAC addresses. For chassis with 64 MAC
addresses, STP uses the extended system ID plus a MAC address to make the bridge ID unique for each
VLAN.
You cannot disable the extended system ID on chassis that support 64 MAC addresses.
Enabling or disabling the extended system ID updates the bridge IDs of all active STP instances, which
might change the spanning-tree topology.
Examples This example shows how to enable the extended system ID:
Switch(config)# spanning-tree extend system-id
Switch(config)#
Related Commands
Release Modification
12.1(12c)EW Support for this command was introduced on the Catalyst 4500 series switch.
Command Description
show spanning-tree Displays spanning-tree information.

Cisco Catalyst 4500 Series Specifications

General

Series	Catalyst 4500 Series
Category	Switch
Layer Support	Layer 2, Layer 3
Form Factor	Modular chassis
Stackable	No
Chassis Slots	3, 6, 7, 10
Power Supply Options	AC, DC
Redundancy	Power supply, Supervisor engine
Network Management	Cisco IOS Software CLI, SNMP, Cisco Prime Infrastructure
Features	Security, QoS
Port Density	Up to 384 ports per chassis
Security Features	802.1X, ACLs, DHCP Snooping, Dynamic ARP Inspection, IP Source Guard
Supervisor Engine	8-E