Listening State; Learning State; Forwarding State; Disabled State - Cisco ONS 15454 Software Feature And Configuration Manual

Chapter 6 Configuring STP and RSTP

Listening State

The listening state is the first state a Layer 2 interface enters after the blocking state. The interface enters
this state when the spanning tree determines that the interface should participate in frame forwarding.
An interface in the listening state performs as follows:
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Learning State

A Layer 2 interface in the learning state prepares to participate in frame forwarding. The interface enters
the learning state from the listening state.
An interface in the learning state performs as follows:
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Forwarding State

A Layer 2 interface in the forwarding state forwards frames. The interface enters the forwarding state
from the learning state.
An interface in the forwarding state performs as follows:
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Disabled State

A Layer 2 interface in the disabled state does not participate in frame forwarding or in the spanning tree.
An interface in the disabled state is nonoperational.
A disabled interface performs as follows:
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Cisco ONS 15454 SONET/SDH ML-Series Multilayer Ethernet Card Software Feature and Configuration Guide, R4.0
January 2004
Discards frames received on the port
Discards frames switched from another interface for forwarding
Does not learn addresses
Receives BPDUs
Discards frames received on the port
Discards frames switched from another interface for forwarding
Learns addresses
Receives BPDUs
Receives and forwards frames received on the port
Forwards frames switched from another port
Learns addresses
Receives BPDUs
Forwards frames switched from another interface for forwarding
Learns addresses
Does not receive BPDUs
Spanning-Tree Interface States
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