Karthik Ramasamy - Network Routing(2018)[Mehdi Ramasamy][9780128007372]

Lawrence Landweber Past John P. Morgridge Chair and Past Department Chairman, Computer Science Department, University of WisconsinMadison, Fellow, Association for Computing Machinery, Recipient of IEEE Award on International Communication, Former President and Chair of the Board of Trustees, Internet Society

My involvement with computer networking started with TheoryNet (1977), an email system for theoretical computer scientists. Later (1981) I helped lead the CSNET (computer science network) project which eventually connected most academic and many industrial computer research groups. In those early days, our efforts were primarily focused on providing connectivity and being able to use applications such as email , ftp , and telnet . However, even in the simple (by today's standards) environment of the 1970s and early 1980s (Arpanet, CSNET, other experimental Internet networks), getting routing right turned out to be quite challenging.

I was fortunate to be part of the NSFNET regional/backbone model development. This is when I began to fully understand the significance of routing in a large-scale multi-domain network and, in particular, the central role of policy issues in such a decentralized environment. As the Internet has become global in scale and ubiquitous over the past decade, routing has become ever more important. Packets must be forwarded efficiently from one end of the world to the other with minimal perception of delay. This has required tremendous efforts on many fronts: how to evolve routing protocols for large-scale loosely-coupled networking environments, how to engineer a network for efficient routing from an operational point of view, how to do efficient packet processing at routers, and how to effectively take into account the complexity of policy issues in the determination of routes. And while over the past two decades there have been many exciting advances, much work remains to be done.

In parallel, we have seen tremendous advances in traditional telephony. The underlying telecommunication system has changed from analog to digital and has incorporated the latest advances in optical technologies and, more recently, voice over IP. Throughout these revolutionary changes, routing has continued to play a critical role.

We are now at a crossroad. Various efforts are underway to determine a framework for next generation networks that allows seamless convergence of services and a platform to more easily create new services. Among other things, this requires a fresh look at routing. To be successful, it is important that we understand what has worked to date. To better understand the issues and complexities we should look at this broadly, considering a variety of