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STP port costs on 3560

asgerbert
Level 1
Level 1

Let me start by saying that I appreciate everyones help with my past posts.

While studying for my BCMSN I log on to our switches here at work. On one of our access switches CS3560 when you do a sho spanning-tree you get this...

Interface Role Sts Cost Prio.Nbr Type

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

Gi0/1 Root FWD 3004 128.1 P2p

Gi0/2 Altn BLK 3004 128.2 P2p

Why is the port cost 3004 (because none of the links add up to anything near that #) , or will I learn about this later?

Thanks.

1 Reply 1

Francois Tallet
Level 7
Level 7

You are probably running uplinfast. Uplinfast increases the bridge priority and the portcost in order to maximize the chance of having this bridge blocking a port (uplinkfast only makes sense on a bridge having alternate ports).

Regards,

Francois

Review Cisco Networking products for a $25 gift card