System Architecture Overview; Packet Forwarding Engine Architecture - Juniper M10 Hardware Manual

Chapter 4

System Architecture Overview

Figure 12: System Architecture

Packet Forwarding Engine Architecture

The router architecture consists of two major components:
•
Packet Forwarding Engine—Performs Layer 2 and Layer 3 packet switching, route
lookups, and packet forwarding.
•
Routing Engine—Provides Layer 3 routing services and network management.
The Packet Forwarding Engine and the Routing Engine perform independently but
communicate constantly through a 100-Mbps internal link. This arrangement provides
streamlined forwarding and routing control and the ability to run Internet-scale networks at
high speeds. Figure 12 illustrates the relationship between the Packet Forwarding Engine
and the Routing Engine.
For a discussion of the architectural components, see the following sections:
•
Packet Forwarding Engine Architecture on page 29
•
Routing Engine Architecture on page 31
The Packet Forwarding Engine performs Layer 2 and Layer 3 packet switching. It can forward
up to 40 for all packet sizes. The aggregate throughput for the router is 6.4 gigabits per second
(Gbps), full duplex. The Packet Forwarding Engine is implemented in application-specific
integrated circuits (ASICs). It uses a centralized route lookup engine and shared memory.
The Packet Forwarding Engine architecture includes the following components:
Routing Engine
100-Mbps link
Packets
Packet Forwarding
in
Engine
System Architecture Overview
Packets
out
29