A B C D
A connected to B fa 0/1 fa 0/2 and D on fa 20/21
B is conected to C fa 0/1 fa0/2
C is conedted to D fa0/1 fa0/2
B is also conedted to D fa 20 fa21
D is conedted to A as well fa 20 and fa21
its a full redundant topolgy
i have 6 vlans swicth A is server and the rest is client
Vlan 234567
i have config mst (on all swicthes)
instance 1 234
instance 2 567
swicth A is root for instance 1
swicth D is root for instance 2
when i do sh spanning tree mst on switch on A
all ports are blocked expept fa0/1 which is connected to switch B
now i tried to config instance 1 on fa 20 and instance 2 on fa 21 (which is connedted to switch D)
i put the comand spanning tree mst 1 port-priority 200 on fa20 and same except instance 2 on fa21
after that when i do sh priority is been changed but the port is still in blocking mode why is that i even try to put cost but still port is in blocking mode