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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
Figure 7-4
Port 2 in Listening State
A port in the listening state performs as follows:
•
Discards frames that are received from the attached segment.
•
Discards frames that are switched from another port for forwarding.
•
Does not incorporate station location into its address database. (There is no learning at this point, so
there is no address database update.)
•
Receives BPDUs and directs them to the system module.
•
Processes BPDUs that are received from the system module.
•
Receives and responds to network management messages.
Filtering
database
Frame
forwarding
System
module
Port 1
BPDUs
All segment
frames
BPDU and network
management frames
All segment
frames
Forwarding
Listening
Station
addresses
Network
management
and data frames
Port 2
S5693
Network
management
frames
Data
frames
BPDUs