Spanning Tree
44
3.3 Examples
UM RedundConfig RSPL
Release 2.0 02/2013
3.3.3 Example of manipulating the tree structure
The Management Administrator soon discovers that this configuration with
bridge 1 as the root bridge
(see on page 40 “Example of determining the root
is invalid. On the paths from bridge 1 to bridge 2 and bridge 1 to bridge
3, the control packets which the root bridge sends to all other bridges add up.
If the Management Administrator configures bridge 2 as the root bridge, the
burden of the control packets on the subnetworks is distributed much more
evenly. The result is the configuration shown here
(see fig. 24)
. The path
costs for most of the bridges to the root bridge have decreased.
Figure 24: Example of manipulating the tree structure
5
P-BID = 32 768
7
P-BID = 32 768
P-BID = 32 768
3
P-BID = 32 768
1
P-BID = 32 768
2
P-BID = 16 384
P-BID = 32 768
6
4
Port 1
Port 2
Root-Bridge
MAC 00:01:02:03:04:06
MAC 00:01:02:03:04:05
Root path
Interrupted path
P-BID
Priority of the bridge identifikation (BID)
= BID without MAC Address