Cisco 7609 User Manual

15-10
Cisco 7600 Series Router Cisco IOS Software Configuration Guide—12.1E
78-14064-04
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. Figure 15-5 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
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

Cisco 7609 Specifications

General

Chassis Slots	9
Switch Fabric Capacity	720 Gbps
Power Supply Options	AC or DC
Product Type	Router
Form Factor	Rack-mountable
Supported Line Cards	Various Cisco 7600 Series line cards
Operating System	Cisco IOS
Management	CLI, SNMP
Forwarding Performance	400 Mpps
Maximum Power Consumption	4000 Watts
Redundancy	Yes
Interfaces/Ports	Various, depending on line cards installed