The Spanning Tree Protocol; The Tasks Of The Stp - Hirschmann RS20 User Manual

Spanning Tree

5.1 The Spanning Tree Protocol

Because RSTP is a further development of the STP, all the following
descriptions of the STP also apply to the RSTP.
5.1.1

The tasks of the STP

The Spanning Tree Algorithm reduces network topologies built with bridges
and containing ring structures due to redundant links to a tree structure. In
doing so, STP opens ring structures according to preset rules by deactivating
redundant paths. If a path is interrupted because a network component
becomes inoperable, STP reactivates the previously deactivated path again.
This allows redundant links to increase the availabiliy of communication.
STP determines a bridge that represents the STP tree structure's base. This
bridge is called root bridge.
Features of the STP algorithm:
 automatic reconfiguration of the tree structure in the case of a bridge
becoming inoperable or the interruption of a data path

the tree structure is stabilized up to the maximum network size (up to
39 hops, depending on the setting for Max Age,
 stabilization of the topology within a short time period

topology can be specified and reproduced by the administrator

transparency for the terminal devices
 low network load relative to the available transmission capacity due to the
tree structure created
UM Redundancy Configuration L2E
Release 7.1 12/2011
5.1 The Spanning Tree Protocol
(see table 13)
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