Internet service providers (ISPs) use routers and routing protocols to connect pieces of the Internet together. This part explores IGPs such as RIP, OSPF, and IS-IS, and also BGP. It includes a look at multicast routing protocols and MPLS, a method of IP switching. ■ Chapter 13—Routing and Peering ■ Chapter 14—IGPs: RIP, OSPF, and IS–IS ■ Chapter 15—BGP ■ Chapter 16—Multicast ■ Chapter 17—IP Switching and Convergence Routing and Routing Protocols PART III . rules ϭ Gig Ethernet Note: All links use 10.0.x.y addressing only the last two octets are shown. FIGURE 13.1 The hosts on the LANs have routing tables as well as the routers. The ISPs on the Illustrated. on the hosts on the LANs, as shown in Figure 13.1. But we’ll also discuss, for the fi rst time, how the two ISPs on the network (called Ace ISP and Best ISP) relate to each other and how their. what they do. We’ll investigate the differences between interior and exterior routing protocols as the terms apply to an ISP. We’ll also talk about routing policies and the role they play on the