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Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
OL-8978-04
Chapter 7 Configuring Spanning Tree
Understanding How Spanning Tree Protocols Work
Learning State
A port in the learning state prepares to participate in frame forwarding. The port enters the learning state
from the listening state.
Figure 7-5
shows a port in the learning state.
A port in the learning state performs as follows:
•
Discards frames that are received from the attached segment.
•
Discards frames that are switched from another port for forwarding.
•
Incorporates station location into its address database.
•
Receives BPDUs and directs them to the system module.
•
Receives, processes, and transmits BPDUs that are received from the system module.
•
Receives and responds to network management messages.
Figure 7-5
Port 2 in Learning State
Filtering
database
Frame
forwarding
System
module
Port 1
BPDUs
All segment
frames
BPDU and network
management frames
All segment
frames
Forwarding
Learning
BPDUs
Station
addresses
Network
management
and data frames
Port 2
S5694
Network
management
frames
Station
addresses
Data
frames
