ABSTRACT
Having read the preceding chapters in this book, one is now aware that routing on a TCP/IP network occurs based on the IP address contained in a datagram. One is also aware of the fact that when entering a host address into an application program, that address must be translated into an IP address because routing occurs based on the destination IP address and not on the host name. Chapter 6 discussed how the address translation process occurs and the role of the domain name system (DNS) and the entries in the domain name servers that form the DNS. What has not been discussed heretofore is the manner by which a router learns where to forward a datagram based on its destination IP address. Thus, the focus of this chapter is on routing and routing protocols that enable datagrams to flow over a TCP/IP network or between separate networks so that they can reach their destination.
