RFC 2004 (rfc2004) - Page 1 of 6

Minimal Encapsulation within IP

Network Working Group                                         C. Perkins
Request for Comments: 2004                                           IBM
Category: Standards Track                                   October 1996


                    Minimal Encapsulation within IP

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Abstract

   This document specifies a method by which an IP datagram may be
   encapsulated (carried as payload) within an IP datagram, with less
   overhead than "conventional" IP encapsulation that adds a second IP
   header to each encapsulated datagram.  Encapsulation is suggested as
   a means to alter the normal IP routing for datagrams, by delivering
   them to an intermediate destination that would otherwise not be
   selected by the (network part of the) IP Destination Address field in
   the original IP header.  Encapsulation may be serve a variety of
   purposes, such as delivery of a datagram to a mobile node using
   Mobile IP.

1. Introduction

   This document specifies a method by which an IP datagram may be
   encapsulated (carried as payload) within an IP datagram, with less
   overhead than "conventional" IP encapsulation [4] that adds a second
   IP header to each encapsulated datagram.  Encapsulation is suggested
   as a means to alter the normal IP routing for datagrams, by
   delivering them to an intermediate destination that would otherwise
   not be selected by the (network part of the) IP Destination Address
   field in the original IP header.  The process of encapsulation and
   decapsulation of a datagram is frequently referred to as "tunneling"
   the datagram, and the encapsulator and decapsulator are then
   considered to be the the "endpoints" of the tunnel; the encapsulator
   node is refered to as the "entry point" of the tunnel, and the
   decapsulator node is refered to as the "exit point" of the tunnel.








Perkins                     Standards Track