Cisco Catalyst LAN Switching
Chapter 18. Layer 3 Switching and the Catalyst 6000/6500s
This chapter covers the following key topics:
Catalyst 6000 Layer 2 Characteristics Discusses the base Catalyst 6000 and 6500 configuration.
MSM Layer 3 Switching The Multilayer Switch Module (MSM) is a router-on-a-stick configuration that provides ASIC-based routing for IP, IPX, and multicast traffic. This section discusses how to configure, use, and deploy these devices.
MSFC Hybrid Mode Layer 3 Switching The Multilayer Switch Feature Card (MSFC) Hybrid Mode is an implementation of Multilayer Switching (MLS) on the Catalyst 6000 platform. It is very similar to using MLS with a Route Switch Module (RSM) on a Catalyst 5000 (only much faster). This section looks at how to configure and implement this technology.
MSFC Native IOS Mode Layer 3 Switching The MSFC Native IOS Mode brings the effectiveness of Cisco's IOS in Layer 2/switched networks to new heights. By allowing the Catalyst 6000 to run a full copy of Cisco's traditional router software for both Layer 3 and Layer2 processing, this represents an exciting and powerful tool for campus designs and implementations.
Note
The term MSFC is used in this chapter to refer to both the MSFC and the Policy Feature Card (PFC). Note that currently the MSFC cannot be purchased without an accompanying PFC. On the other hand, a PFC can be purchased and used without an MSFC. This configuration supports QoS and access list functionality (but not Layer 3 switching).
The Catalyst 6000 family represents a significant step forward in switching technology while retaining a strong foundation in existing and proven Cisco designs. As this chapter discusses, the Catalyst 6000s and 6500s can act as faster versions of Layer 2 Catalyst 5000s. For shops starved for Gigabit Ethernet bandwidth and port density, this can be extremely useful. However, it is the Layer 3 switching capabilities of the Catalyst 6000s that set them apart from other switches and is the primary focus of this chapter.
Because of these powerful new features, the Catalyst 6000s are intentionally discussed in the last chapter of this book. In essence, the 6000s draw on material learned in virtually every prior chapter of this book but also add exciting new capabilities. For example, Chapter 4, "Configuring the Catalyst," discussed the XDI/CatOS Catalyst user interface of set, clear, and show commands. In one configuration, Catalyst 6000s use all of these commands and concepts. However, by taking advantage of the Catalyst 6000 Native IOS Mode, you can instantly convert your box into a full-fledged Cisco router (an entirely new, but familiar, user interface)! Similarly, the Catalyst 6000 can be used to implement most of the Layer 3 switching designs discussed in Chapter 11, "Layer 3 Switching." However, it goes beyond these features by offering a completely new approach to Layer 3 switch configuration and management the previously mentioned Native IOS Mode. The Native IOS mode builds on the material discussed in Chapter 14, "Campus Design Models," and Chapter 15, "Campus Design Implementation," by supporting more flexible Layer 3 switching designs.