show vlan internal

Unanswered Question
smothuku Wed, 09/19/2007 - 21:02

Hi ,

It display information about the internal VLAN allocation.

Usage Guidelines

In some cases, the output displays the following:

workaround vlan

A workaround VLAN is used to enable the PFC-based policing on the PWAN1 main interface. Without the workaround VLAN, the packets hit the PFC policer twice for PWAN1 because the same VLAN is used when packets traverse the local bus before and after PXF processing.

Usage Guidelines

Entering the show vlan internal usage command displays the OSM interfaces and subinterfaces in addition to the regular Ethernet interfaces.

To display the associated subinterfaces, enter the show cwan vlan command. The show cwan vlan command displays the mapping between the WAN subinterface and the internal VLANs in use.


This example shows how to display the current internal VLAN allocation:

Router# show vlan internal usage

VLAN Usage

---- --------------------

1025 -

1026 -

1027 -

1028 -

1029 Port-channel6

1030 GigabitEthernet1/2

1032 FastEthernet3/20

1033 FastEthernet3/21

1129 -

This example shows how to display the internal VLAN allocation for a specific VLAN:

Router# show vlan id 1030 internal usage

VLAN Usage

---- --------------------

1030 GigabitEthernet1/2



smothuku Wed, 09/19/2007 - 22:08

Hi ,

The new internal VLAN allocation feature simplifies VLAN management by providing greater flexibility in assigning both "internal" and "customer" VLANs. Traditionally, internal VLANs have been allocated for WAN interfaces, routed interfaces, and certain other features starting from VLAN 1006 (by default); when allocated, these internal VLANs are not available for customer VLAN assignment. The new internal VLAN allocation feature allows internal VLAN allocation to be assigned in descending order, beginning with VLAN ID 4096 rather than ascending from VLAN ID 1006. This allows customers to assign VLAN IDs in an ascending fashion without internal VLAN ID restrictions in the middle of the ID range.

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.

?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.

?You can configure ascending internal VLAN allocation (from 1006 and up) or descending internal VLAN allocation (from 4094 and down).

?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).

Cheers :)



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