Large-Scale IP Network Solutions (CCIE Professional Development)

Router Architecture

In Chapter 1, “Evolution of Data Networks,” you learned about the evolution of router technology within the early Internet. Essentially two approaches were presented:

• A single computer/central-processor approach, such as the original NSFNET “fuzzball” routers

• The parallel switching/multi-processor nodal switching subsystems (the successor)

Each approach is discussed in more detail in the following sections.

Note

A router isolates the link-layer broadcast domains of subnetworks, forwards IP packets between the domains, decrements the TTL, and sometimes performs media translation and fragmentation. To make a forwarding decision, the router exchanges topological information about the network with other routers.

Single CPU Designs ...