[c-nsp] 3550 learning state

[Pelle]

Hi.

>  What's happening is that when an ethernet interface is connected or disconnected 5 of the ports on the switch move back to a learning state.
>
>  The ports that are changing to a learning state are both trunk & access ports.

Are you running MST on the uplink ports, i.e is there a MST listener
upstream? If not, this is the expected result. All ports "external" to
an MST-region will go through the port state transitions whenever a
topology change occurs. It looks like your upstream ports are indeed
"external".

You can check this with the command "show spanning-tree mst". Here is
one example:

3550-24T#sh spanning-tree mst

##### MST0    vlans mapped:   none

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/15           Desg FWD 200000    128.15   P2p Bound(PVST)
Gi0/1            Desg FWD 20000     128.25   P2p
Gi0/2            Root FWD 20000     128.26   P2p

Gi0/1 and Gi0/2 are the upstream ports running MST and Fa0/15 is
connected to an switch outside the MST-region (an "external" port).

>  spanning-tree mst configuration
>   instance 10 vlan 50, 69-70, 92-96, 98-99, 291, 350, 498-509, 550, 603
>   instance 10 vlan 605-606, 701, 703, 750, 761, 800-802
>   instance 15 vlan 1-49, 51-68, 71-91, 97, 100-290, 292-349, 351-497, 510-549
>   instance 15 vlan 551-602, 604, 607-700, 702, 704-749, 751-760, 762-799
>   instance 15 vlan 803-4094

I would not recommend having this very complex MST instance mapping
(if possible). Keep it simple is the mantra (here too).

-- 
Pelle