Cisco 6500 with Sup-2T & MET Reserved VLAN

Cisco recently launched IOS 15 for Cisco Catalyst 6500 series switches with SUP-2T. This version of IOS had reserved few VLANs for MET (Multicast Expansion Table). These VLANs are called Internal Use VLANs

In case you are intrested in some hands-on, you can try the below suggested procedure

switch(config)#vlan 3990
VLAN id: 3990 is an internal vlan id - cannot use it to create a VTP VLAN.

Reserved VLANs can be checked with the command “sh vlan internal usage”:
 
switch #sh vlan internal 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)
3968 MET reserved VLAN
3969 MET reserved VLAN
3970 MET reserved VLAN
3971 MET reserved VLAN
...
4030 MET reserved VLAN
4031 MET reserved VLAN

Due some code being backported from NX-OS to IOS 15, VLANs from 3968 to 4031 are now reserved for MET usage. However, if you are deploying these switches on working environments you may have the need to use some of these VLANs. If this is the case, you can change the VLAN range with the following command:
 
switch (config)#vlan internal reserved met vlan 3904
The new MET VLAN will take effect after reload.
Please reload, or no change will be made
Configuration MET VLAN value is 3904
Operation MET VLAN value is 3968

After you reload the switch the new VLAN range will be applied:

switch #sh vlan internal usage
...
3904 MET reserved VLAN
3905 MET reserved VLAN
3906 MET reserved VLAN
...
3965 MET reserved VLAN
3966 MET reserved VLAN
3967 MET reserved VLAN
 
More information about MET (Multicast Expansion Table) can be found here.

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