Question about Spanning Tree (2 switches, 2 segments between them)

Vask3nVask3n Posts: 517Member
This diagram basically describes the topology I am looking at:

So obviously in this case we would follow the STP process but I have a question in regard to tiebreakers when cost is the same.

1. Elect the root switch based on lowest bridge ID, Look at priority first then MAC
2. All ports on the root switch are forwarding ports
3. For every non-root switch, choose a path to the root switch that is the lowest cost path and that path is the root port
In this case, if both paths in the diagram are equal cost links, is the tiebreaker the lowest interface ID??
4. The port in step 3 becomes a DESIGNATED PORT (DP). The other end of this designated port becomes a blocking port (discarding in RSTP)

Can someone please spot check me on this process?
Working on MS-ISA at Western Governor's University


  • JeanMJeanM Posts: 1,117Member

    1) Lowest cost path to the root switch (from the switch that will get the
    root port).
    2) Lowest upstream (towards the root switch) Bridge ID.
    3) Lowest upstream (towards the root switch) port priority.
    4) Lowest upstream (towards the root switch) port ID.
    2015 goals - ccna voice / vmware vcp.
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