Juniper JUNOS - NETWORK OPERATION GUIDE REV1 User Manual

Understanding Key Router Components ! 95
Chapter 12: Monitoring Key Router Components
Data Flow Through the M7i Router Packet Forwarding Engine
Data flows through the M7i router Packet Forwarding Engine in the following
sequence shown in Figure 14. Use of ASICs promotes efficient movement of data
packets through the system.
Figure 14: M7i Router Packet Forwarding Engine Components and Data Flow
1. Packets arrive at an incoming networking interface.
2. The networking interface passes the packets to the CFEB, where the integrated
ASIC processes the packet headers, divides the packets into 64-byte data cells,
and distributes the data cells throughout the memory buffer.
3. The integrated ASIC on the CFEB performs a route lookup for each packet and
decides how to forward it.
a. If services are configured for the packet, the integrated ASIC reassembles
the packet and passes it to the services interface.
b. The services interface passes the packet to the CFEB, where the integrated
ASIC processes the packet, divides the packet into 64-byte cells, and
distributes the data cells throughout the memory buffer.
c. The integrated ASIC performs a second route lookup for each packet and
decides how to forward it.
4. The integrated ASIC notifies the outbound networking interface.
5. The integrated ASIC reassembles data cells stored in shared memory into data
packets as they are ready for transmission and passes them to the outbound
networking interface.
6. The outbound networking interface transmits the data packets.
g003225
Routing
Engine
Midplane
Controller
ASIC
Controller
ASIC
Packet
out
Packet
in
CFEB
Services
Interface
Controller
ASIC
Networking
Interface
Networking
Interface
Integrated
ASIC
Memory
Buffer

Juniper JUNOS - NETWORK OPERATION GUIDE REV1 Specifications

General

Brand	Juniper
Model	JUNOS - NETWORK OPERATION GUIDE REV1
Category	Software
Language	English