Transport Provider Interface (TPI), Version 2
Copyright © 2000 The Open Group


Open Group Technical Standard
Transport Provider Interface (TPI), Version 2
Document Number: C810
ISBN: 1-85912-246-9

©January 2000, The Open Group All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the copyright owners.

Any comments relating to the material contained in this document may be submitted to The Open Group at:

The Open Group
Apex Plaza
Forbury Road
Berkshire, RG1 1AX
United Kingdom
or by electronic mail to:


The Open Group

The Open Group is a vendor and technology-neutral consortium which ensures that multi-vendor information technology matches the demands and needs of customers. It develops and deploys frameworks, policies, best practices, standards, and conformance programs to pursue its vision: the concept of making all technology as open and accessible as using a telephone.

The mission of The Open Group is to deliver assurance of conformance to open systems standards through the testing and certification of suppliers' products.

The Open group is committed to delivering greater business efficiency and lowering the cost and risks associated with integrating new technology across the enterprise by bringing together buyers and suppliers of information systems.

Membership of The Open Group is distributed across the world, and it includes some of the world's largest IT buyers and vendors representing both government and commercial enterprises.

More information is available on The Open Group Web Site at

Open Group Publications

The Open Group publishes a wide range of technical documentation, the main part of which is focused on development of Technical and Product Standards and Guides, but which also includes white papers, technical studies, branding and testing documentation, and business titles. Full details and a catalog are available on The Open Group Web Site at

In addition, The Open Group publishes Product Documentation. This includes product documentation-programmer's guides, user manuals, and so on-relating to the DCE, Motif, and CDE. It also includes the Single UNIX Documentation, designed for use as common product documentation for the whole industry.

Versions and Issues of Specifications

As with all live documents, Technical Standards and Specifications require revision to align with new developments and associated international standards. To distinguish between revised specifications which are fully backwards compatible and those which are not:


Readers should note that Corrigenda may apply to any publication. Corrigenda information is published on The Open Group Web Site at

Ordering Information

Full catalog and ordering information on all Open Group publications is available on The Open Group Web Site at

This Document
The Transport Provider Interface (TPI) defines an interface for drivers that provide transport services. The TPI specifies the set of messages and their formats which the driver must generate or process.

TPI was originally specified by UNIX International (UI). UI intellectual property rights were subsequently acquired by UNIX System Laboratories (USL), who in turn were later acquired by Novell Inc. See also the Acknowledgements page. The Open Group first published its TPI CAE Specification in July 1997 (Document Number C615).

This TPI specification is now revised and published as an Open Group Technical Standard. It supersedes the TPI CAE Specification C615.

Intended Audience
This specification assumes the reader is familiar with OSI Reference Model terminology, OSI transport services and STREAMS.
The structure of this specifications is:
Typographical Conventions
The following typographical conventions are used throughout this document:

Trade Marks

Motif®, OSF/1®, UNIX®, and the "X Device" are registered trademarks and IT DialToneTM; and The Open GroupTM; are trademarks of The Open Group in the U.S. and other countries.


The original TPI Specification was produced by UNIX International (UI). UI intellectual property rights subsequently passed to UNIX System Laboratories (USL), who in turn were acquired by Novell Inc.

The Open Group acknowledges Novell's contribution of their TPI 2.01 specification as the base document from which the February 1997 TPI Specification (C615) was developed.

Referenced Documents

The following documents are referenced in this specification:

ISO/IEC 8072

ISO 8072:1986, Information Processing Systems - Open Systems Interconnection - Transport Service Definition.


UNIX Press (A Prentice Hall Title) book "STREAMS Modules and Drivers", published 1992, ISBN 0-13-066879-6.

XNS, Issue 5

CAE Specification, February 1997, Networking Services, Issue 5 (ISBN: 1-85912-165-9, C523), published by The Open Group.

Why not acquire a nicely bound hard copy?
Click here to return to the publication details or order a copy of this publication.

Contents Next section Index