[c-nsp] Spanning-tree stupidity - MST not obeying cost / priority?

[Rolf Mendelsohn]

Hi Guys,

I have the follow topology:


		SW1 (Root)------------------------SW3------------------SW5
		|     |						     |
		|     |						     |
		SW1------------------|		     |
		      -------------------SW4------------

The topology is messy because of the fact that the switches are all over town 
running with different wireless links due to Radio/Geographical issues.

I have MST instance 0 serving vlan's 1-1005.

spanning-tree extend system-id
spanning-tree mst configuration
spanning-tree mst hello-time 1
spanning-tree mst forward-time 6
spanning-tree mst max-age 8
spanning-tree mst max-hops 8

SW1/SW2 = 3550
SW3         = WS-3560
SW4/SW5 = C2400ME

SW1 bridge id 4096
SW2 bridge id 8192
SW4 bridge id 16384

NO matter how high i set the cost and port-priority settings on the link from 
SW1 --- SW3, I cannot force the traffic to go via SW4----> SW1 (which is the 
way I would like it to go by default).

Any idea's / hints would be much appreciated.

This is from SW3

MST0
  Spanning tree enabled protocol mstp
  Root ID    Priority    4096
             Address     0014.6a12.8c00
             Cost        0
             Port        12 (FastEthernet0/10)
             Hello Time   1 sec  Max Age  8 sec  Forward Delay  6 sec

  Bridge ID  Priority    32768  (priority 32768 sys-id-ext 0)
             Address     001a.2f06.6f00
             Hello Time   1 sec  Max Age  8 sec  Forward Delay  6 sec

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/1            Desg FWD 100         0.3    P2p				---Connected to SW4
Fa0/3            Desg FWD 200000    128.5    P2p
Fa0/4            Desg FWD 200000    128.6    P2p
Fa0/6            Desg FWD 200000     64.8    P2p
Fa0/7            Desg FWD 200000    128.9    Edge P2p
Fa0/8            Desg FWD 2000000   128.10   Shr
Fa0/10           Root FWD 20000000  240.12   P2p			---Connected to SW1
Fa0/11           Desg FWD 200000    128.13   P2p
Fa0/12           Desg FWD 200000    128.14   Edge P2p

cheers
/rolf