Switch/Router Architectures

7Architectures with Bus-Based Switch Fabrics: Case Study—Cisco Catalyst 6000 Series Switches

7.1 Introduction

The Cisco Catalyst 6000 family of switch/routers consists of the Catalyst 6000 and 6500 Series that are designed to deliver high-speed Layer 2 and 3 forwarding solutions for service provider and enterprise networks. This chapter describes the different Catalyst 6000 series switch/router architectures [CISCCAT6000, MENJUS2003]. The Catalyst 6000 series supports several architectural options in terms of Layer 3 routing and forwarding capabilities.

Layer 3 routing and forwarding capabilities in the Catalyst 6000 and 6500 switches are handled by two important components: the Multilayer Switching Feature Card (MSFC) and the Policy Feature Card (PFC). These two key components, along with other functions required for system configuration and operation, are implemented on a specialized module in the Catalyst 6000/6500 called the Supervisor Engine.

The PFC provides the hardware-based forwarding engine functions required to perform in the Catalyst 6000/6500, Layer 2 and 3 forwarding, quality of service (QoS) classification, policing, shaping, priority queuing, and QoS and security access control list (ACL) processing. For Layer 3 forwarding, the PFC requires the services of a routing engine (or route processor) in the chassis to generate the necessary routing information needed for the flow/route cache or forwarding tables used by the Layer 3 forwarding engine.

The MSFC provides ...