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Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
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Chapter 9 Configuring VLANs
Understanding How VLANs Work
VLAN Ranges
Note You must enable the extended system ID to use 4096 VLANs (see the “Understanding the Bridge ID”
section on page 15-3).
With Release 12.1(13)E and later releases, Catalyst 6500 series switches support 4096 VLANs in
accordance with the IEEE 802.1Q standard. These VLANs are organized into several ranges; you use
each range slightly differently. Some of these VLANs are propagated to other switches in the network
when you use the VLAN Trunking Protocol (VTP). The extended-range VLANs are not propagated, so
you must configure extended-range VLANs manually on each network device.
Table 9-1 describes the VLAN ranges.
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 (see the “Understanding the
Bridge ID” section on page 15-3).
Table 9-1 VLAN Ranges
VLANs Range Usage
Propagated
by VTP
0, 4095 Reserved For system use only. You cannot see or use these VLANs.
1 Normal Cisco default. You can use this VLAN but you cannot delete it. Yes
2–1001 Normal For Ethernet VLANs; you can create, use, and delete these
VLANs.
Yes
1002–1005 Normal Cisco defaults for FDDI and Token Ring. You cannot delete
VLANs 1002–1005.
Yes
1006–4094 Extended For Ethernet VLANs only. No