Cisco Systems EA6500 Manual De Usuario
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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
Learning State
A Layer 2 LAN port in the learning state prepares to participate in frame forwarding. The Layer 2 LAN
port enters the learning state from the listening state.
port enters the learning state from the listening state.
shows a Layer 2 LAN port in the
learning state.
Figure 15-5 Interface 2 in Learning State
A Layer 2 LAN port in the learning state performs as follows:
•
Discards frames received from the attached segment.
•
Discards frames switched from another port for forwarding.
•
Incorporates end station location into its address database.
•
Receives BPDUs and directs them to the system module.
•
Receives, processes, and transmits 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
BPDU and network
management frames
All segment
frames
frames
Forwarding
Learning
BPDUs
Station
addresses
Network
management
and data frames
Port 2
S5694
Network
management
frames
Station
addresses
Data
frames