sh vlan int usage?

[dvtestguy]

I'm looking to implement Q-in-Q from a 4948 (supports Q-in-Q) to a 6506 (which doesn't support Q-in-Q).

I've used VLAN ranges 1-999, and looking to use 1000-1099 for Q-in-Q.

When I type in "sh vlan bri" I can clearly see VLANs 1-999 Active, however, when I happened to type in "sh vlan int usage" it shows the output below.

Any idea what the outputs means? Thanks...

Cisco6500IOS#sh vlan int usage

VLAN Usage
---- --------------------
1006 online diag vlan0
1007 online diag vlan1
1008 online diag vlan2
1009 online diag vlan3
1010 online diag vlan4
1011 online diag vlan5
1012 PM vlan process (trunk tagging)
1013 L3 multicast partial shortcuts
1014 FastEthernet4/1
1016 FastEthernet4/10
1025 FastEthernet4/16
1027 FastEthernet4/7
1028 FastEthernet4/9

 

[ADB100]

These are VLAN's you can't use....

Internally the Catalyst allocates VLAN id's for it's own use. I am not too sure about the 'online diag', 'PM vlan process' or 'L3 multicast' but the ones assigned to the FastEthernet ports are because these are routed ports (no switchport).
It seems the catalyst (and all the L3 IOS Catalysts do this) needs to assign VLAN id's to ports even though they are not actually a VLAN, if you get my meaning.

If you attempt to use these VLAN's the CLI will reject it and tell you they are allocated internally. You can however change whether it uses VLAN's 1006 and up or 4094 and down with the global command:

vlan internal allocation policy [ascending, descending]

HTH

Andy

 

[dvtestguy]

Thanks Andy, this is a great help!