Listening State; Learning State; Forwarding State; Disabled State - Cisco Catalyst 3750-X Software Configuration Manual

Chapter 20 Configuring STP
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Listening State

The listening state is the first state a Layer 2 inte rface enters after the blocking state. Theinterface enters
this state when the spanning tree decides that the interface should participate in frame forwarding.
An interface in the listening state performs these functions:
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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 these functions:
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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 these functions:
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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 these functions:
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OL-21521-01
Does not learn addresses
Receives BPDUs
Discards frames received on the interface
Discards frames switched from another interface for forwarding
Does not learn addresses
Receives BPDUs
Discards frames received on the interface
Discards frames switched from another interface for forwarding
Learns addresses
Receives BPDUs
Receives and forwards frames received on the interface
Forwards frames switched from another interface
Learns addresses
Receives BPDUs
Discards frames received on the interface
Discards frames switched from another interface for forwarding
Does not learn addresses
Does not receive BPDUs
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
Understanding Spanning-Tree Features
20-7