User manual

FL SWITCH MM HS
5-22
PHOENIX CONTACT 6874_en_09
5.2.5.6 Flowchart for Specifying the Root Path
Figure 5-16 Flowchart for specifying the root path
5.2.5.7 Extended Configuration
It may be useful to actively specify the topology that is formed due to the Spanning Tree
Protocol and to not leave it to the random MAC addresses of the switches involved.
Non-blocking/blocking data paths can thus be influenced and a load distribution specified.
It may also be useful to explicitly disable the Spanning Tree Protocol at ports that do not
participate in Spanning Tree so as to benefit from the fast forwarding function.
The Spanning Tree Protocol must also be disabled at individual ports if two different
network segments - both using Spanning Tree - are to be coupled via these ports without
the two tree structures merging into a large Spanning Tree.
Determine path to root switch
Same path costs?
Same priority for switches
(bridge identification)?
Same priority for
individual ports?
Lowest path costs
Root path
Highest priority for switch
Root path
Highest priority for
port Root path
Lowest port number
Root path
Path to root switch is determined
Yes
Yes
Yes
No
No
No