This chapter covers an overview of routing, including how to set up static routes and how dynamic routing protocols—distance vector, link state, and hybrid protocols— function. Chapter 10 covers the configuration of two distance vector routing protocols, and Chapter 11 covers the configuration of a link state routing protocol and a hybrid routing protocol. | CCNA CISCO CERTIFIED NETWORK ASSOCIATE 9 Routing Introduction Problems with Distance Vector Protocols Two-Minute Drill Self Test 2 Chapter 9 Routing Introduction FTI. . he last two chapters focused on products and protocols that function at layer-2. This chapter moves up one layer in the OSI Reference Model to discuss layer-3 the network layer. Layer-3 devices are generically called routers. Routers basically have two functions 1. To find a layer-3 path to a destination network 2. To move packets from one interface to another to get a packet to its destination In order to accomplish the first function a router will need to Learn about routers it is connected to in order to learn the networks that they know about Find locations of destination network numbers Choose a best path to each destination Maintain the most up-to-date routing information about how to reach destination networks In order to accomplish its second function the router will need to examine the destination IP address in an incoming IP packet determine the network number of the destination look in its routing table and switch the packet to an outgoing interface. As you will see in this chapter the routing table contains a list of destination network numbers the status of these networks which interface the router should use to reach the destination and which neighboring router the router should use if the destination is more than one hop away. This chapter covers an overview of routing including how to set up static routes and how dynamic routing protocols distance vector link state and hybrid protocols function. Chapter 10 covers the configuration of two distance vector routing protocols and Chapter 11 covers the configuration of a link state routing protocol and a hybrid routing protocol. Types of Routes A router can learn a route via one of two methods static and dynamic. A static route is a route that is manually configured on the router. There are actually two ways that a router can learn a .
