OSI connectionless transport services on top of UDP: Version 1 (RFC1240)
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2000-Sep-12
Internet Society Requests For Comment (RFCs)
C. Shue: AUTHOR [+3]
Status of this Memo
Network Working Group C. Shue
Request for Comments: 1240 Open Software Foundation
Wang Laboratories, Inc.
Cabletron Systems, Inc.
OSI Connectionless Transport Services on top of UDP
Status of this Memo
This document describes a protocol for running OSI Connectionless
service on UDP. This RFC specifies an IAB standards track protocol
for the Internet community, and requests discussion and suggestions
for improvements. Please refer to the current edition of the "IAB
Official Protocol Standards" for the standardization state and status
of this protocol. Distribution of this memo is unlimited.
1. Introduction and Philosophy
The Internet community has a well-developed, mature set of layered
transport and network protocols, which are quite successful in
offering both connection-oriented (TCP) and connectionless (UDP)
transport services over connectionless network services (IP) to end-
users. Many popular network applications have been built directly on
top of the TCP and UDP over the past decade. These have helped the
Internet services and protocols to become widely-spread de facto
standards. In the past few years, the ISO and CCITT have defined a
well-architected set of upper layer standards which include
connection-oriented and connectionless session, presentation, and
application layer services and protocols. These OSI upper layer
standards offer valuable services to application developers (e.g.,
dialogue control, transfer syntax, peer authentication, directory
services, etc.) which are not currently offered by the TCP/IP
As indicated in RFC 1006, it is desirable to offer the OSI upper
layer services directly in the Internet without disrupting existing
facilities. This permits a more graceful convergence and transition
strategy from IP-based networks to OSI-based networks in the future.
Using the approach of RFC 1006, this memo specifies how to offer OSI
connectionless transport service using the User Datagram Protocol
(UDP) [RFC768] of the TCP/IP suite.
We will define a Transport Service Access Point (TSAP) which appears
to be identical to the services and interfaces defined in ISO 8072
and its Addendum 1, but we will in fact implement the ISO T-UNIT-DATA
protocol on top of UDP. By this means, OSI TPDU's can be delivered
across the Internet network, and OSI connectionless upper layers can
operate fully without knowledge of the fact that they are running on
top of UDP/IP. In essence, the OSI T-UNIT-DATA service will use UDP
as its connectionl...