Chapter 3. Static Routing

• The Route Table

• Configuring Static Routes

  Case Study: Simple Static Routes

  Case Study: Summary Routes

  Case Study: Alternative Routes

  Case Study: Static Floating Routes

  Case Study: Load Sharing

  Case Study: Recursive Table Lookups

• Troubleshooting Static Routes

  Case Study: Tracing a Failed Route

  Case Study: A Protocol Conflict

An important observation from Chapter 2, "TCP/IP Review," is that the data link/physical layers and the transport/network layers, as defined by the OSI model, perform very similar duties : They provide the means for conveying data from a source to a destination across some path. The difference is that the data link/physical layers provide communications across a physical path , whereas the transport/network layers provide communications across a logical or virtual path made up of a series of data links.

Further, Chapter 2 showed that for communications to take place across a physical path, certain information about data link identifiers and encapsulations must be acquired and stored in a database such as the ARP cache. Similarly, information that the transport/network layers require to do their job must also be acquired and stored. This information is stored in the route table , also known as the forwarding database .

This chapter examines what sort of information is required to route a packet, how that information is stored in the route table, how to enter the information into the database, and some techniques for building a routed internetwork by entering the proper information into the proper routers' route tables.