Cisco Cisco IOS Software Release 12.4(15)T

These are the prerequisites for configuring extended VLAN ID:

You should understand how to configure VLANs. For information on configuring VLANs, see the

 chapter in the

 

Routers (Fixed) Software Configuration Guide. 

The reduced MAC address feature is required to support 4000 VLANs. Cisco IOS Release 12.1(14)E1 
and later releases support chassis with 64 or 1024 MAC addresses. For chassis with 64 MAC addresses, 
Spanning Tree Protocol (STP) uses the extended system ID (which is the VLAN ID) plus a MAC address 
to make the bridge ID unique for each VLAN. (Without the reduced MAC address support, 4096 VLANs 
would require 4096 MAC addresses on the switch.)

The spanning-tree extended system-ID feature must be enabled. For information on enabling the 
extended system ID, see the

 section in the “Configuring 

Spanning Tree and IEEE 802.1s MST” chapter in the Cisco 7600 Series Cisco IOS Software 
Configuration Guide, 12.1E.

The spanning-tree extended system ID is enabled permanently on chassis that support 64 MAC 
addresses. 

The following Cisco routers support the Extended VLAN ID feature:

Cisco 800 series routers, including models 851, 857, 871, 876, 877, 878

Cisco 1700 series routers, including models 1711, 1712, 1751, 1751V, 1760 

Cisco 1800 series routers, including models 1801, 1802, 1803, 1811, 1812, 1841

Cisco 2600 series routers, including models 2610XM, 2611XM, 2620XM, 2621XM, 2650XM, 
2651XM, 2691

Cisco 2800 series routers, including models 2801, 2811, 2821, 2851

Cisco 3600 series routers, including models 3620, 3640, 3640A, 3660

Cisco 3700 series routers, including models 3725, 3745

Cisco 3800 series routers, including models 3825, 3845

These are the restrictions for configuring normal and extended VLANs:

VLAN 1 and VLANs 1002–1005 are default VLANs. Default VLANs are created automatically and 
cannot be configured or deleted by users.

VLANs 0 and 4095 are reserved by the IEEE 802.1Q standard and you cannot create, delete, or modify 
them. These VLANs are not displayed.

You cannot create a VLAN in the extended range when the reduced MAC address feature is disabled.

You cannot disable the reduced MAC address feature while a user-configured VLAN in the extended 
range is configured. 

The vlan database mode does not support extended VLAN configuration.