[c-nsp] L3 VLAN showing up but no physical interface bound or physical interface down.

[jason.plank at comcast.net]

Drew,

Did you look at spanning-tree and confirm that the vlan was no longer in spanning-tree? The switch will not turn the vlan interface down if the vlan is still in use in spanning-tree.

--
Regards,

Jason Plank
CCIE #16560
e: jason.plank at comcast.net

 -------------- Original message ----------------------
From: Drew Weaver <drew.weaver at thenap.com>
>                 Hi there. We have seen this issue on two separate Catalyst 6500s 
> in the past two weeks or so, we've noticed that on occasion either with a Layer 
> 3 VLAN with no FastEthernet/GigabitEthernet port attached to it, or with one 
> attached to it which is either down or administratively shutdown that the Layer 
> 3 VLAN refuses to notice that it should in fact "give it a rest" as they say. 
> Has anyone seen anything similar to this in the past. We aren't running VTP or 
> any multi-switch/campus wide VLANs. All of our VLANs are contained intra-switch. 
> Both switches are running the same version of code. The only remedy we've found 
> for solving this issue is to simply blow away the VLAN (which is usually what 
> we're trying to do when we notice this anyway), but we are a little concerned by 
> what could be the cause.
> 
> Thanks.
> -Drew
> 
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