Spanning Tree Protocol Parameters
Spanning Tree Concepts A-5
A.3.5 Handling Duplicate Paths
When the active topology of the network is determined, all packets between any two nodes in the
network use only one path. Where a duplicate path exists, the non-designated port is put into a
blocking state.
A.3.6 Remapping Network Topology
If there is a change in the network topology due to a failure or the removal or addition of any active
components, the active topology also changes. This may trigger a change in the state of some
blocked ports.
The following describes the five (5) states of the ports when using spanning tree:
•Blocking: A port in this state does not participate in the transmission of frames, thus preventing
duplication arising through multiple paths existing in the active topology of the bridged LAN.
•Listening: A port in this state is preparing to participate in the transmission of frames. The
transmission of frames is temporarily disabled in order to prevent temporary loops, which may
occur in a bridged LAN during the lifetime of this state as the active topology of the bridged
LAN changes.
•Learning: A port in this state is preparing to participate in the transmission of frames.
•Forwarding: A port in this state is participating in the transmission of frames.
•Disabled: A port in this state does not participate in the transmission of frames or the operation
of the spanning tree process.