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Transition Networks
SISGM
–CHAS L2/L3 Switch User Guide
33625 Rev. B
Page
37
of
234
4.4 STP/RSTP/MSTP
4.4.1 STP/RSTP
STP (Spanning Tree Protocol), and its advanced versions RSTP (Rapid Spanning Tree Protocol)
and MSTP (Multiple Spanning Tree Protocol), are designed to prevent network loops and provide
network redundancy. Network loops occur frequently in large networks as when two or more paths
run to the same destination, broadcast packets may get in to an infinite loop and hence causing
congestion in the network. STP can identify the best path to the destination, and block all other
paths. The blocked links will stay connected but inactive. When the best path fails, the blocked
links will be activated. Compared to STP which recovers a link in 30 to 50 seconds, RSTP can
shorten the time to 5 to 6 seconds.
STP Bridge Status
This page shows the status for all STP bridge instances.
The STP Bridges parameters are described below.
Label
Description
MSTI
The bridge instance; also links to the STP detailed bridge status.
Bridge ID
The bridge ID of this bridge instance.
Root ID
The bridge ID of the currently selected root bridge.
Root Port
The switch port currently assigned the root port role.
Root Cost
Root path cost. For a root bridge, this is zero. For other bridges, it is
the sum of port path costs on the least cost path to the Root Bridge.
Topology Flag
The current state of the Topology Change Flag for the bridge instance.
Topology
Change Last
The time since last Topology Change occurred.
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