TCP/IP First-Step [Electronic resources] نسخه متنی

Chapter 11. How Do I Get There from Here?

What You Will Learn

After reading this chapter, you should be able to answer the following questions:

What is a router?

What are a router's six primary functions?

What are two approaches to calculating best paths?

Which portion of an IP address does a router use to route?

What is a routing protocol?

What does a routing protocol do?

At what layer(s) of the OSI reference model does a router separate different networks?

At what layer(s) of the OSI reference model does a router interconnect networks?

What is a hop and why is it significant in routing?

What is a distance vector?

A whole other set of protocols exists that isn't exactly part of the TCP/IP suite, but is absolutely indispensable to an IP network. These routing protocols determine how to get your IP packets from your machine to where they need to go.

Routing protocols provide the critical functions that enable two or more networks to communicate by sharing information about machines connected to each network, compare notes about different ways to reach any given destination machine, and pick the best path to those destinations. Without trying to cause a philosophical debate regarding what "the best" actually means, suffice it to say lots of valid ways can solve the same problemusually with different "correct" answers! This chapter shows you some of the different options for routing between networks and kicks around their benefits and weaknesses.