Rapid Spanning Tree Protocol (Rstp) - 3Com 3C17300-US Implementation Manual

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HAPTER SING
Rapid Spanning Tree
Protocol (RSTP)
R F
ESILIENCE EATURES
The protocol is a part of the IEEE 802.1D bridge specification. To explain
STP 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 802.1w standard. RSTP is enabled by default.
3Com recommends that you use the Rapid Spanning Tree Protocol
feature (enabled by default) to provide optimum performance for your
network and ease of use.
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 Fast-Forwarding configuration of edge ports provided by
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the 'Fast Start' feature. Fast Start allows a port that is connected to an
endstation to begin forwarding traffic after only four seconds; this
"Auto" setting is default for front panel ports. During these four
seconds RSTP (or STP) will detect any misconfiguration that may cause
a temporary loop and react accordingly.
If you have Fast Start disabled on a port, the Switch will wait for 30
seconds before RSTP (or STP) lets the port forward traffic. If you set
Fast Start to "Enable" mode, ports enter the forwarding mode
immediately after becoming active. This mode should be used for
ports connected to edge devices in an AppleTalk network.
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.
it is possible for some ports on a Switch to operate in RSTP
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(802.1w) mode, and other ports, for example those connected to a
legacy Switch, to operate in STP (802.1D) mode.
you have an option to force your Switch to use the legacy 802.1D
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version of Spanning Tree, if required.