Specifications

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Catalyst 4500 Series Switch Cisco IOS Command Reference—Release IOS XE 3.3.0XO(15.1(1)XO)
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Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
spanning-tree extend system-id
spanning-tree e xtend system- id
To enable the extended system ID feature on a chassis that supports 10 24 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 keywo rds.
Defaults Enab led on systems that do not prov ide 1024 MAC addresses.
Command Modes Global c onfiguratio n mode
Usage Guidelines R eleases 12 .1(13)E a nd later support cha ssis wi th 64 or 1024 MAC addr esses. For chassis with 64 MAC
addresses, STP use s the ext ended sy stem ID pl us a MAC address to mak e the br idge ID u nique for each
VLAN.
You cannot disable the extended system I D on chassis that support 64 MAC add resses.
Enabling or disabling the extended system ID updates the bridge IDs of all active STP instances, which
might change the spanning-tr ee topology.
Examples This exampl e shows how to enable the extende d system ID:
Switch(config)# spanning-tree extend system-id
Switch(config)#
Related Commands Command Description
show spanning-tree Displays spanning-tree information.