Go CCIE Go!! - A Cisco Certified Internetwork Expert

Gents, I found the issue. there were 2 issues indeed. First I forgot to set the dot1q-tunnel ( :-S ) .. Second. And that I didn’t know… the end switches were running ISL trunks. When I changed that to Dot1q trunks, I got it working fine…. I thought i’d work evenif it was ISL…. on the Edge routers…anyway… it’s working now..

———- Forwarded message ———- From: Daniel Valle Date: Mon, Mar 31, 2008 at 5:53 PM Subject: MSTP and dot1q-tunnel To: groupstudy
Hi GS,
does MultipleSTP and do1q tunnels compatible ? I made a trunk between SW1 and SW3 via SW4, and configured SW4 with do1q tunnel. All 6 interfaces between them have the following config: (SW4) interface FastEthernet0/X switchport access vlan 100 switchport mode access l2protocol-tunnel cdp l2protocol-tunnel stp l2protocol-tunnel vtp l2protocol-tunnel point-to-point pagp l2protocol-tunnel point-to-point lacp l2protocol-tunnel point-to-point udld no cdp enable !
Sw1 is the Root and SW3 should reach SW1 via PO14 ( po from SW3 , through dot1q-tunnel in SW4 and then reaching SW1) .No matter what I do , the PO14 in SW3 keeps in Designated port. if I make the same config beween the direct links between SW1 and SW3 they work fine,
Rack3SW3#show spanning-tree mst 2
##### MST2 vlans mapped: 2-100 Bridge address 0019.aab4.fe00 priority 32770 (32768 sysid 2) Root address 0019.aa6f.4f00 priority 24578 (24576 sysid 2) port Po23 cost 68660 rem hops 18
Interface Role Sts Cost Prio.Nbr Type —————- —- — ——— ——– ——————————– Po14 Desg FWD 1 128.176 P2p Po23 Root FWD 66660 128.248 P2p ! this is the config for SW1 and SW3
SW3 ! interface Port-channel14 switchport trunk encapsulation isl switchport mode trunk spanning-tree mst 1 cost 1 spanning-tree mst 2 cost 1 end ! ! SW1 ! ! interface Port-channel14 switchport trunk encapsulation isl switchport mode trunk spanning-tree mst 1-2 port-priority 0 !
Any Ideas are welcome!