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3750 switch stack, wierd output of show spanning-tree

Hello there,

So I have five 3750 switches in a stack. Show version, show switch, show switch stack-ports all show that they work properly. However when I do show spanning-tree then it has a port named "St5". On some vlans it's FWR and others BLK... Does anybody know what it's? Thanks!!

Interface Role Sts Cost Prio.Nbr Type

---------------- ---- --- --------- -------- --------------------------------

Po1 Desg FWD 3 128.488 P2p

Po2 Desg FWD 3 128.496 P2p

Po3 Desg FWD 3 128.504 P2p

St5 Back BLK 100 128.876 P2p

1 ACCEPTED SOLUTION

Accepted Solutions

Re: 3750 switch stack, wierd output of show spanning-tree

This is the stack port, which is used to sync STP information between members of the stack. The state is irrelevant here (don't worry about the BLK state). It should be hidden from the user. You can only see it because you have "debug spanning-tree event" enabled.

Regards,

Francois

2 REPLIES

Re: 3750 switch stack, wierd output of show spanning-tree

This is the stack port, which is used to sync STP information between members of the stack. The state is irrelevant here (don't worry about the BLK state). It should be hidden from the user. You can only see it because you have "debug spanning-tree event" enabled.

Regards,

Francois

New Member

Re: 3750 switch stack, wierd output of show spanning-tree

k so it won't cause any issues? Cool Thanks!

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