[c-nsp] 3550 VLAN interfaces

[Volodymyr Yakovenko]

On Thu, Aug 26, 2004 at 12:34:00PM -0400, Dan Armstrong wrote:
>Can anyone think of a functional difference on a 3550 between creating a vlan 
>interface, and assigning a switchport (switchport mode access) to that VLAN, 
>versus just putting an IP address on an interface (no switchport)?

There is at least one issue - if you are using IGP and redundant topology, 
'no switchport' makes it much quicker to inform IGP process that interface 
went down and IGP topology should be recalculated.

Same behaviour could be achieved if you are using separate VLAN per 
'switchport' _and_ this 'switchport' is the only one, which belong to
that VLAN - if there are no any operational ports (access or trunk) which
uses some VLAN, that VLAN will be placed by IOS in operational down state.

Unfortunately there is no easy way to insctruct IOS to use some VLAN on that,
and only that interface. If you are using trunks you should manualy disable
that VLAN on all trunk ports.

>Operationally to keep things consistent, it would be easier to make vlan 
>interfaces and assign ports to VLANs, but I don't want to take a "hit" in 
>performance somehow....
>
>Thanks,
>Dan.
>
>
>
>_______________________________________________
>cisco-nsp mailing list  cisco-nsp at puck.nether.net
>https://puck.nether.net/mailman/listinfo/cisco-nsp
>archive at http://puck.nether.net/pipermail/cisco-nsp/

-- 
Regards,
Volodymyr.