Switch/Router Architectures

10Architectures with Shared-Memory-Based Switch Fabrics: Case Study—Cisco Catalyst 8500 CSR Series

10.1 Introduction

The Catalyst 8500 campus switch/routers (CSRs) are modular networking devices that provide wire speed Layer 2 and Layer 3 packet forwarding and services [CISCCAT8500]. The Catalyst 8500 family of devices comprises the Catalyst 8510 and 8540 switch/routers. This family of high-speed switch/routers is targeted for campus or enterprise backbones.

The Catalyst 8500 family of devices support both IP and IPX routing standards but the focus of this chapter will be on the IP routing features. The IPX protocol has been deprecated and is no more in use. Based on architecture categories described in Chapter 3, the architectures discussed here fall under “architectures with shared-memory-based switch fabrics and distributed forwarding engines” (see Figure 10.1).

Figure 10.1 Architectures with shared-memory-based switch fabrics and distributed forwarding engines.

10.2 Main Architectural Features of the Catalyst 8500 Series

The key features of the Catalyst 8500 CSR include wire-speed Layer 3 IP unicast and multicast forwarding over 10/100 Mb/s Ethernet and Gigabit Ethernet (GbE) interfaces. The switch/router supports the configuration of virtual LANs (VLANs) between switches via the IEEE 802.1Q standard and Cisco Inter-Switch Link (ISL) trunking protocol (a Cisco proprietary ...