Abstract-While it is technically pleasing to believe that IP will dominate all forms of communication, our delight in its elegance is making us overlook its shortcomings. IP is an excellent means to exchange data, which explains its success. It remains ill-suited as a means to provide many other types of service; and is too crude to form the transport infrastructure in its own right. To allow the continued success of IP, we must be open-minded to it living alongside, and merging with, other techniques (such as circuit switching) and protocols that are optimized to different needs.
I. INTRODUCTIONWhatever the initial goals of the Internet, there are two main characteristics that seem to account for its success: Reachability and Heterogeneity. IP provides a simple, single, global address to reach every host, enables unfettered access between all hosts, and adapts the topology to restore reachability when links and routers fail. IP hides heterogeneity in the sense that it provides a single, simple service abstraction that is largely independent of the physical links over which it runs. As a result, IP provides service to a huge variety of applications and operates over extremely diverse link technologies.The growth and success of IP has given rise to some widely held assumptions amongst researchers, the networking industry and the public at large. One common assumption is that it is only a matter of time before IP becomes the sole global communication infrastructure, dwarfing and eventually displacing existing communication infrastructures such as telephone, cable and TV networks. IP is already universally used for data networking in wired networks, and is being rapidly adopted for data communications in wireless and mobile networks. IP is increasingly used for both local and long-distance voice communications, and it is technically feasible for packetswitched IP to replace SONET/SDH.A related assumption is that IP Routers (based on packet-switching and datagram routing) will become the most important, or perhaps only, type of switching device inside the network. This is based on our collective belief that packet-switching is inherently superior to circuit switching because of the efficiencies of statistical multiplexing, and the ability of IP to route around failures. It is widely assumed that IP is simpler than circuit switching, and should be more economical to deploy and manage. And with continued advances in the underlying technology, we will no doubt see faster and faster links and routers throughout the Internet infrastructure. It is also widely assumed that IP will become the common convergence layer for all communication infrastructures. All communication services will be built on top of IP technology. In addition to information retrieval, we will stream video and audio, place phone calls, hold video-conferences, teach classes, and perform surgery.On the face of it, these assumptions are quite reasonable. Technically, IP is flexible enough to support all communication needs, from best-effort to real-time. ...