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

Rapid Spanning Tree

1.1 The Spanning Tree Protocol

Because RSTP is a further development of the STP, all the following descrip-
tions of the STP also apply to the RSTP.

1.1.1 The Tasks of the STP

The Spanning Tree Algorithm reduces network topologies that are set up
using bridges, and that have ring structures with redundant connections, to a
tree structure. In doing this, STP divides up the ring structures on the basis
of specified rules by deactivating redundant paths. If a path is interrupted by
mistake, the STP activates the path just deactivated. This enables redundant
connections for increased data safety.
In forming the tree structure, the STP determines what is known as a root
bridge. This forms the basis of the STP tree structure.
Features of the STP algorithm:
D
it reconfigures automatically the tree structure in case of a bridge failure
or break in a data path,
D
It stabilizes the tree structure up to the maximum network size (up to 39
hops, depending on the setting for "Max. Age"),
D
It stabilizes within a short, known time,
D
It produces a reproducible topology that can be pre-defined by manage-
ment,
D
It is transparent to the terminal equipment,
D
by creating a tree structure it results in a low network load compared to
the available transmission capacity.
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1.1 The Spanning Tree Protocol
Redundancy L3P
Release 3.0 01/07