I read that every time a BPDU is forwarded by a switch, the message age is incremented by 1.

Also the switch will wait "max age" - "message age" for a new BPDU.

I'd like to know what happens if a BPDU is going through some many switches that the message age becomes greater than the configured max age?

My guess is that the timer waiting from another BPDU will be set to 0 and stop as soon as it is started. It will then start a root election process.

Is that it?

1 Answer 1


Check IEEE 802.1D Clause 17.9: When message age reaches max age the BPDU is discarded. This ensures that no outdated information keeps circulating.

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