Example Of Determining The Root Path - Hirschmann RS20 User Manual

Spanning Tree
5.3 Example of determining the
root path
You can use the network plan
fig. 31) for determining the root path. The administrator has specified another
priority in the bridge identification for each bridge. The bridge with the
smallest numerical value for the bridge identification takes on the role of the
root bridge, in this case, bridge 1. In the example all the sub-paths have the
same path costs. The protocol blocks the path between bridge 2 and bridge 3
as a connection from bridge 3 via bridge 2 to the root bridge would result in
higher path costs.
The path from bridge 6 to the root bridge is interesting:
 The path via bridge 5 and bridge 3 creates the same root path costs as
the path via bridge 4 and bridge 2.
 The bridges select the path via bridge 4 because the value 28,672 for the
priority in the bridge identifier is smaller than value 32,768.

There are also 2 paths between bridge 6 and bridge 4. The port identifier
is decisive here.
UM Redundancy Configuration L2E
Release 7.1 12/2011
5.3 Example of determining the root
(see fig. 32) to follow the flow chart
path
(see
67