T640 System Architecture Description

The router architecture cleanly separates control operations from packet forwarding operations. This design eliminates processing and traffic bottlenecks, permitting the router to achieve high performance. Control operations in the router are performed by the host subsystem, which runs Junos OS to handle routing protocols, traffic engineering, policy, policing, monitoring, and configuration management. Forwarding operations in the router are performed by the Packet Forwarding Engines, which consist of hardware, including ASICs, designed by Juniper Networks.

The T640 Core Router has two main architectural components:

• Routing Engine—This component provides Layer 3 routing services and network management.
• Packet Forwarding Engines—These high-performance, ASIC-based components provide Layer 2 and Layer 3 packet switching, route lookups, and packet forwarding.

The Routing Engine and the Packet Forwarding Engines perform their primary tasks independently, although they constantly communicate through multiple 100-Mbps links. This arrangement streamlines forwarding and routing control and runs Internet-scale backbone networks at high speeds. Figure 1 shows the relationship between the Routing Engine and the Packet Forwarding Engines.

Figure 1: Router Architecture