Siemens SCALANCE W786-xPRO Operating Instructions Manual page 141

If necessary, modify the following parameters to specify how the (rapid) spanning tree
algorithm operates:
● Enable (R)STP check box
● Version drop-down list box
● Bridge Priority input box
● Max Age input box
SCALANCE W786-xPRO
Operating Instructions, Release 08/2007, C79000-G8976-C221-02
Select the Enable Spanning Tree check box if you want to use the (rapid) spanning tree
algorithm. If the check mark is not set, all ports are automatically in the 'Forwarding'
status.
The version decides whether the Rapid Spanning Tree protocol (RSTP) is used or
whether the device is operated in compatibility mode of the Spanning Tree protocol
(STP).
The identification of the most efficient connection is always related to the root bridge, a
network component that can be considered as a root element of a tree-like network
structure. With the "Bridge Priority" parameter you can influence the selection of the root
bridge.
The bridge with the highest priority (in other words, with the lowest value for this
parameter) becomes the root bridge. If several network components in a network have
the same priority, the station whose MAC address has the lowest numeric value will
become the root bridge. Both parameters, bridge priority and MAC address together form
the Bridge Identifier. Since the root bridge manages all path changes, it should be located
as centrally as possible due to the propagation time of the frames. The value for the
bridge priority is a whole multiple of 4096 with a range of values from 0 through 61440.
Max Age is the time that a bridge waits for a configuration frame (BPDU). When this time
Configuration / project engineering
5.6 Configuration with Web Based Management
141