A few weeks ago, we deployed some new Cisco Catalyst 6513 with Sup2T supervisor engines as access switches. During the initial configuration, we realized that Cisco had introduced some new reserved VLANs on IOS15 for internal usage:
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
LINKS
More information about MET (Multicast Expansion Table) – see PDF page 31
About David Barroso
