RFC 1622 (rfc1622) - Page 2 of 16

Pip Header Processing

RFC 1622                 Pip Header Processing                  May 1994


Conventions

   All functions in this specification are mandatory.

1.  Introduction

   Pip is an internet protocol intended as the replacement for IP
   version 4.  Pip is a general purpose internet protocol, designed to
   handle all forseeable internet protocol requirements.  This
   specification defines the Pip header processing for Routers and
   Hosts.

   The design of Pip is fundamentally different from that of previous
   internetwork protocols.  Pip is designed to be as general as
   possible, but without significantly compromising performance.
   Because of Pip's generality, it can handle forseeable routing and
   addressing requirements.  It is hoped that it will be able to handle
   most if not all future routing and addressing requirements.

   There are many detailed aspects of Pip that provide this generality
   that are not discussed here.  It is useful, however, to mention one
   general aspect.  That is, Pip strives to remove as much "functional
   semantics" from the base specification as possible.  Pip defines a
   packet header and forwarding rules that can include many different
   functional semantics (that is, routing, addressing, and flow
   paradigms).  Therefore, the reader may often find him or herself
   asking "But how do you do foo with Pip?" The answer to this sort of
   question belongs in companion documents to the basic Pip spec.

   Pip can be thought of as a mechanism for triggering actions in hosts
   and routers, just as a machine language can be thought of as a
   mechanism for triggering actions in CPUs.  The machine language has
   no functional semantics outside of the specific actions it triggers
   (move this register, write that memory location, etc.).  But, the
   machine language is a very powerful tool upon which functional
   semantics are built.  Likewise, Pip is a powerful tool upon which
   routing, addressing, and flow functions can be built.














Francis