The router architecture consists of two major components:
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 20 illustrates the relationship between the Packet Forwarding Engine and the Routing Engine.
Figure 20: System Architecture
For a discussion of the architectural components, see the following sections: