The Illustrated Network- P36:In this chapter, you will learn about the protocol stack used on the global public Internet and how these protocols have been evolving in today’s world. We’ll review some key basic defi nitions and see the network used to illustrate all of the examples in this book, as well as the packet content, the role that hosts and routers play on the network, and how graphic user and command line interfaces (GUI and CLI, respectively) both are used to interact with devices. | PART Routing and Routing Protocols III 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 CHAPTER Routing and Peering 13 What You Will Learn In this chapter you will learn about how routing differs from switching the other network layer technology. We ll compare connectionless and connection-oriented networking characteristics and see how quality of service QoS can be supported on both. You will learn what a routing protocol is and 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 modern Internet. In Chapter 9 we introduced the concept of forwarding packets hop by hop across a network of interconnected routers and LANs. This process is loosely called routing and that chapter comprised a first look at routing tables and the associated forwarding tables . In this chapter we ll discuss how ISPs manipulate their routing tables with routing policies to influence the flow of traffic on the Internet. This chapter will focus more closely on the routing tables on hosts. In Chapters 14 and 15 we discuss in more detail the routing tables and routing policies on the network routers. This chapter will look at the routing tables on the hosts on the LANs as shown in Figure . But we ll also discuss for the first time how the two ISPs on the network called Ace ISP and Best ISP relate to each other and how their routing tables ensure that traffic flows most efficiently between LAN1 and LAN2. For example it s obviously more effective to send LAN1-LAN2 traffic over the link between P4 and P2 .
