17 Dynamic routing

This chapter covers

  • The advantages of dynamic routing over static routing
  • The types of dynamic routing protocols
  • How a router decides which routes to enter in its routing table
  • Activating dynamic routing protocols with the network command

After focusing on Layer 2 concepts for the previous several chapters, in this chapter, we return to the topic of routing—how routers forward packets between networks. In chapter 9, we learned about static routing, in which an administrator manually configures routes to build a router’s routing table. When using dynamic routing, the topic of this chapter, routers communicate with each other and build their routing tables automatically. Although static routing has its uses, dynamic routing provides several advantages that we will examine in this chapter. We will cover elements of the following exam topics:

  • 3.1 Interpret the components of routing table
  • 3.2 Determine how a router makes a forwarding decision by default
  • 3.3 Configure and verify IPv4 and IPv6 static routing
  • 3.4 Configure and verify OSPFv2

17.1 Dynamic routing vs. static routing

17.1.1 Adaptability

17.1.2 Scalability

17.2 Types of routing protocols

17.2.1 Interior gateway protocols

17.2.2 Exterior gateway protocols

17.3 Route selection

17.3.1 The metric parameter

17.3.2 The administrative distance parameter

17.3.3 Route selection examples

17.4 The network command

Summary