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+--- Thread: Question NA348 (/thread-206.html)
Question NA348 - ryanf - 08-20-2009
Just wondering if the answer should be "Switch4, port fa0/11"?
Re: Question NA348 - kbates - 12-14-2009
Same here. If switch 4 is receiving lower BPDUs on Fa0/2 from switch 3 on port Fa0/1 (lower port index), wouldn't that put Fa0/11 on switch 4 in the blocking state?
Re: Question NA348 - jakesteramma - 12-14-2009
I agree with you guys. According to the following literature I found online, the port with the "Lowest Sending Port ID" is elected ROOT!! Therefore, Port Fa0/11 on Switch 4 should assume the discarding role.
The following criteria are used by each spanning tree node to select a path to the root bridge:
1. Lowest root bridge ID - Determines the root bridge
2. Lowest cost to the root bridge - Favors the upstream switch with the least cost to root
3. Lowest sender bridge ID - Serves as a tie breaker if multiple upstream switches have equal cost to root
4. Lowest sender port ID - Serves as a tie breaker if a switch has multiple (non-Etherchannel) links to a single upstream switch