Inside Cisco IOS Software Architecture

Chapter 3. Shared Memory Routers

This chapter covers the following key topics:

• Hardware Architecture for Shared Memory Routers

• Packet Buffers for Shared Memory Routers

• Packet Switching on a Shared Memory Router

In the previous two chapters, we covered IOS’ basic architecture and switching methods in the abstract. To understand how IOS actually works, though, it’s helpful to see how it operates on a real router. Because IOS is so closely coupled to the hardware on which it runs, each implementation has its own platform-specific features.

This chapter examines a very basic IOS implementation—the one for a group of routers known collectively as shared memory routers. Shared memory routers consist of several products, including the Cisco ...