The Internet Protocol (IP) is rapidly reaching the end of its useful life as a global internetwork protocol. Fundamentally, the IP address space is too small to indefinitely satisfy current Internet growth rates. A related problem with IP is the poor scaling of internet routing.

To find a longer-term solution to these problems, an effort has been initiated to develop the next generation IP (IPng), a replacement protocol for IP. IPng is required to solve the address depletion and scaling problems of IP. In addition, IPng will add new features to IP.

The Simple Internet Protocol Plus (SIPP), a proposed next-generation IP analyzed in this paper, solves these problems with larger internet layer addresses. In addition, SIPP provides a number of advanced routing and addressing capabilities, including mobility, extended variable-length addressing, provider selection, and certain forms of multicast. These capabilities are all achieved through a single mechanism, a generalization of the IP loose source routing. The paper describes the methods used to achieve advanced routing and addressing functions in SIPP.

The paper is worth reading because SIPP will probably be adopted as the basis for IPng. It is written for networking people; a certain amount of knowledge of current IP problems and routing methods is necessary to appreciate and understand the arguments.