RFC 1873 (rfc1873) - Page 1 of 4
Message/External-Body Content-ID Access Type
Alternative Format: Original Text Document
Network Working Group E. Levinson
Request for Comments: 1873 Accurate Information Systems, Inc.
Category: Experimental J. Clark
December 1995
Message/External-Body Content-ID Access Type
Status of this Memo
This memo defines an Experimental Protocol for the Internet
community. This memo does not specify an Internet standard of any
kind. Discussion and suggestions for improvement are requested.
Distribution of this memo is unlimited.
Abstract
When using MIME [MIME] to encapsulate a structured object that
consist of many elements, for example an SGML [SGML] document, a
single element may occur several times. An encapsulation normally
maps each of the structured objects elements to a MIME entity. It is
useful to include elements that occur multiple time exactly once. To
accomplish that and to preserve the object structure it is desirable
to unambiguously refer to another body part of the same message.
The existing MIME Content-Type Message/External-Body access-types
allow a MIME entity (body-part) to refer to an object that is not in
the message by specifying how to access that object. The Content-ID
access method described in this document provides the capability to
refer to an object within the message.
1. Introduction
Consider a MIME multipart entity several of whose body parts contain
the same data (body) but different parameters or Content-* headers.
Representing those body parts without duplicating the data in each
one promotes efficient use of resources (bandwidth and storage
space). To achieve these benefits an access-type is defined that
permits one message part to refer to another one in the same message.
Levinson & Clark Experimental