Hi,
The following information applies to VLAN ranges:
•Layer 3 LAN ports, WAN interfaces and subinterfaces, and some software features use internal VLANs in the extended range. You cannot use an extended range VLAN that has been allocated for internal use.
•With Release 12.1(13)E and later releases, to display the VLANs used internally, enter the show vlan internal usage command. With earlier releases, enter the show vlan internal usage and show cwan vlans commands.
•With Release 12.1(13)E and later releases, you can configure ascending internal VLAN allocation (from 1006 and up) or descending internal VLAN allocation (from 4094 and down). In previous 12.1EX releases that support 4096 VLANs, internal VLANs are allocated from 1006 and up.
•Switches running the Catalyst operating system do not support configuration of VLANs 1006-1024. If you configure VLANs 1006-1024, ensure that the VLANs do not extend to any switches running Catalyst software.
•You must enable the extended system ID to use extended range VLANs.
and check out the below link reagrding extended vlan range support in cisco
http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.1E/native/configuration/guide/vlans.html
Hope that helps out your query !!
Regards
Ganesh.H
