Cisco Systems EA6500 Manual De Usuario
15-11
Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
78-14099-04
Chapter 15 Configuring STP and IEEE 802.1s MST
Understanding How STP Works
Forwarding State
A Layer 2 LAN port in the forwarding state forwards frames, as shown in
. The Layer 2 LAN
port enters the forwarding state from the learning state.
Figure 15-6 Interface 2 in Forwarding State
A Layer 2 LAN port in the forwarding state performs as follows:
•
Forwards frames received from the attached segment.
•
Forwards frames switched from another port for forwarding.
•
Incorporates end station location information into its address database.
•
Receives BPDUs and directs them to the system module.
•
Processes BPDUs received from the system module.
•
Receives and responds to network management messages.
Filtering
database
Frame
forwarding
System
module
module
Port 1
BPDUs
All segment
frames
frames
All segment
frames
frames
Forwarding
Forwarding
BPDUs
Station
addresses
Network
management
and data frames
Port 2
S5695
Network
management
and data frames
Station
addresses