[nsp] "multi vlan"

[Spencer Garrett]

On Tue, 1 Jul 2003, Brian Wallingford wrote:

> Scenario:
> 
> Cisco 7206vxr -> Cisco 3524XL -> dumb l2 switch
> 
> We've been running a bunch of simple (read, a single vlan on the 3524
> trunked to a subif on the 7206)  vlans flawlessly for a number of years.
> 
> Now, I need to use the same "dumb" l2 switch for two different vlans, from
> two different subif's on the 7200.  Currently, I've got two crossconnects
> from the 3500 to the dumb switch (one for each vlan), which is causing
> annoying, though not service-affecting problems (Jul  1 22:44:44
> edt: %RTD-1-ADDR_FLAP: FastEthernet0/6 relearning 5 addrs per min
> Jul  1 22:45:44 edt: %RTD-1-ADDR_FLAP: FastEthernet0/6 relearning 6 addrs
> per min
> Jul  1 22:50:14 edt: %RTD-1-ADDR_FLAP: FastEthernet0/6 relearning 5 addrs
> per min).
> 
> Though performance is fine, this strikes me as sloppy.  I've tried using a
> single crossconnect from the 3500 to the dumb switch, and "switchport
> multi vlan [vlan1] [vlan2], but connectivity is lost.
> 
> I'm probably missing something blatantly obvious.  A cluebat upside my
> head would be most appreciated.

This can't be done without cooperation from the dumb l2 switch.  Instead
you should use one vlan and put a secondary address on the 7206
subinterface.  Two networks - one vlan.  The other solution would be to
buy a second dumb l2 switch.

Spencer