Chapter 9 Configuring Vlan; Vlan Ranges - Cisco 7609 Configuration Manual

Understanding How VLANs Work

VLAN Ranges

Note You must enable the extended system ID to use 4096 VLANs (see the
section on page
With Release 12.1(13)E and later releases, Cisco 7600 series routers 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
Table 9-1
VLANs
0, 4095
1
2–1001
1002–1005 Normal
1006–4094 Extended
The following information applies to VLAN ranges:
•
•
•
•
•
Cisco 7600 Series Router Cisco IOS Software Configuration Guide—12.1E
9-2
15-3).
describes the VLAN ranges.
VLAN Ranges
Range Usage
Reserved For system use only. You cannot see or use these VLANs.
Normal Cisco default. You can use this VLAN but you cannot delete it. Yes
Normal For Ethernet VLANs; you can create, use, and delete these
VLANs.
Cisco defaults for FDDI and Token Ring. You cannot delete
VLANs 1002–1005.
For Ethernet VLANs only.
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
Bridge ID" section on page 15-3).
Chapter 9 Configuring VLANs
"Understanding the Bridge ID"
Propagated
by VTP
—
Yes
Yes
No
"Understanding the
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