Rapid Spanning Tree Protocol; Rapid Spanning Tree Protocol (Rstp) - 3Com SuperStack 3 3812 Implementation Manual

40 C 4: U
HAPTER SING
Rapid Spanning
Tree Protocol
Rapid Spanning Tree
Protocol (RSTP)
R F
ESILIENCE EATURES
The Rapid Spanning Tree Protocol makes your network more resilient to
link failure and also provides a protection from loops — one of the major
causes of broadcast storms. RSTP is enabled by default on your Switch.
To be fully effective, RSTP or STP must be enabled on all Switches in your
network.
RSTP provides the same functionality as STP. For details on how the two
systems differ, see
The following sections explain more about STP and the protocol features
supported by your Switch. They cover the following topics:
What is STP?
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How STP Works
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Using STP on a Network with Multiple VLANs
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The protocol is a part of the IEEE Std 802.1w-2001, bridge specification.
To explain RSTP more effectively, your Switch will be referred to as a
bridge.
The Rapid Spanning Tree (RSTP) is an enhanced Spanning Tree feature.
RSTP implements the Spanning Tree Algorithm and Protocol, as defined in
the IEEE Std 802.1w-2001.
Some of the benefits of RSTP are:
Faster determination of the Active Spanning Tree topology throughout
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a bridged network.
Support for bridges with more than 256 ports.
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Support for the Fast-Forwarding configuration of edge ports provided
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by the 'Fast Start' feature. Fast Start allows a port that is connected to
an endstation to begin forwarding traffic after only 4 seconds. During
this 4 seconds RSTP (or STP) will detect any misconfiguration that may
cause a temporary loop and react accordingly.
Easy deployment throughout a legacy network, through backward
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compatibility:
it will default to sending 802.1D style BPDU's on a port if it receives
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packets of this format.
"How RSTP Differs to STP" on page 45.