Example: Determination Of Root Paths - Hirschmann PowerMICE User Manual

Rapid Spanning Tree

1.1.4 Example: determination of root paths

Using the network diagram
flow chart (see Fig. 4)
fined a different priority in the bridge identification for each bridge. The bridge
with the numerically smallest bridge identification (in this case, bridge 1) is
selected as the root bridge. In this example the partial paths all have the
same path costs. The path between bridge 2 and bridge 3 is removed becau-
se a connection from bridge 3 to the root bridge via bridge 2 would result in
twice the path costs.
The path from bridge 6 to the root bridge is interesting:
D
The path via bridges 5 and 3 generates the same root path costs as the
path via bridges 4 and 2.
D
The path via bridge 4 is selected because the numerical value 28 672 for
the priority in the bridge identifier is less than the numerical value 32 768.
D
There are however two paths between bridge 6 and bridge 4. In this case,
the larger port priority is decisive.
20
(see Fig. 5), it is possible to follow the logic in the
for determining the root path. The Administrator de-
1.1 The Spanning Tree Protocol
Redundancy L3P
Release 3.0 01/07