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STP Root Bridge Calculator

Compare two bridges to see which wins the STP root election.

Bridge A

Bridge B

A effective priority32769
B effective priority28673
WinnerBridge B wins (lower effective priority).

Election order: lowest effective priority first, then lowest MAC.

How to read the result

Election order: lowest bridge ID wins. Bridge ID = effective priority (config priority + VLAN) first, then lowest MAC on ties.

Example

32768 vs 28672 → Bridge B wins on lower priority

FAQ

Valid priorities?

Multiples of 4096 from 0 to 61440, e.g. 0, 4096, 24576, 32768.

What breaks ties?

If effective priorities match, the bridge with the lowest MAC address wins.