Intel ER8100STUS - Express 8100 Router, Reference Manual

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Reference.bok : Chapter10 111 Wed Apr 22 10:58:08 1998
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Spanning Tree Algorithm
WAN Bridging Services
Network extension
If the network is extended, the Spanning Tree Algorithm must be capable of
adapting automatically to the new topology.
Spanning Tree in the Intel Express 8100 Router
Bridges and links
Each bridge is identified by a Bridge ID, and each link on a bridge is identified
by a Port ID.
Bridge links can be either disabled or enabled. links which are enabled can be in
one of the following states:
Listening
The initial state for a bridge, in which the bridges send messages to one another
to establish the network topology and the optimal paths to the different segments
of the network. Normal data is not transmitted.
Blocking
The bridge enters the Blocking State if a path with higher priority is found to exist
during the Listening State. Normal data is not transmitted.
Learning
The bridge enters the Learning State if no path with a higher priority is found dur-
ing the Listening State. Learned entries are entered in the Unicast Destination
Forwarding Table. Normal data is not transmitted.
Forwarding
The bridge enters the Forwarding State after having been in the Learning State
for a predefined time period. Normal data is transmitted.
Bridge A
Dropout
Bridge C
Bridge D
Bridge B
Blocked
by Bridge B
#1
#3
#2
Matchbox Router
Matchbox Router
Matchbox Router
Matchbox Router
Matchbox Router
Matchbox Router
Matchbox Router
Matchbox Router
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