SIP is a candidate for IPng. The purpose of the working group
   is to finalize the SIP family of protocols, and to foster the early
   development and experimentation of this protocol.

   There are two major characteristics of the SIP proposal: it is very
   much a continuation of IP, and it aims at maximum simplicity. A
   short hand definition of SIP could be ``64-bit IP with useless
   overhead removed.''

   Following the IP model, SIP uses globally-unique addresses,
   hierarchically structured for efficient routing. SIP addresses are
   64 bits long, which is believed to be adequate to scale the Internet up
   to,  say, thousands of internet-addressable devices in every office,
   every residence, and every vehicle in the world.

   The quest of simplicity in SIP has been described as parallel to the
   RISC philosophy. The minimal SIP header contains only those fields
   which are necessary to achieve our goal: routing packets efficiently
   in a very large internet. As a result of this design philosophy, the
   SIP header is much simpler than the IP header. Simplicity
   facilitates high-performance implementation and increases the
   likelihood of correct implementation.

   Contrary to several other IPng candidates, the SIP effort is
   focused mostly on the description of the final state, not on the
   description of the transition. This is due to a coordination with
   the IPAE Working Group, which has already engaged an intensive study
   of transition problems, with SIP in mind as a final state.