World Library  
Flag as Inappropriate
Email this Article

Open Systems Interconnection

Article Id: WHEBN0000040244
Reproduction Date:

Title: Open Systems Interconnection  
Author: World Heritage Encyclopedia
Language: English
Subject: Link layer, Remote Operations Service Element protocol, Telecommunications Management Network, X.500, X/Open Transport Interface
Collection: 1977 Introductions, Iso/Iec 7498, Itu-T Recommendations
Publisher: World Heritage Encyclopedia

Open Systems Interconnection

Open Systems Interconnection (OSI) is an effort to standardize ITU-T.[1]


  • History 1
  • Criticism 2
  • See also 3
  • References 4
  • Further reading 5
  • External links 6


Prior to OSI, networking was largely either government-sponsored (ARPANET in the US, CYCLADES in France) or vendor-developed and proprietary standards (such as the System network architecture (SNA) of IBM and DECnet of Digital Equipment Corporation). A Experimental Packet Switched system in the UK circa 1973, also identified the need to define higher level protocols. The NCC (UK) publication 'Why Distributed Computing' which came from considerable research into future configurations for computer systems, resulted in the UK presenting the case for an international standards committee to cover this area at the ISO meeting in Sydney in March 1977. OSI was hence an industry effort, attempting to get industry participants to agree on common network standards to provide multi-vendor interoperability. It was common for large networks to support multiple network protocol suites, with many devices unable to interoperate with other devices because of a lack of common protocols. However, while OSI developed its networking standards, TCP/IP came into widespread use on multivendor networks for internetworking, while on the local network level both Ethernet and token ring gained prominence.

The OSI reference model was a major advance in the teaching of network concepts. It promoted the idea of a consistent model of protocol layers, defining interoperability between network devices and software. The OSI model was defined in raw form in Washington, DC in February 1978 by Hubert Zimmermann of France and the refined standard was published by the ISO in 1984.


The OSI protocol suite that was specified as part of the project was considered by many, such as computer scientist Andrew S. Tanenbaum, to be too complicated and inefficient, and to a large extent unimplementable.[2] Taking the "forklift upgrade" approach to networking, it specified eliminating all existing protocols and replacing them with new ones at all layers of the stack. This made implementation difficult, and was resisted by many vendors and users with significant investments in other network technologies. In addition, the protocols included so many optional features that many vendors' implementations were not interoperable.[2]

Although the OSI model is often still referred to, the Internet's TCP/IP protocol suite is used in lieu of the OSI protocols. TCP/IP's pragmatic approach to computer networking and two independent implementations of simplified protocols made it a practical standard.[2] Some protocols and specifications in the OSI stack remain in use, one example being IS-IS, which was specified for OSI as ISO/IEC 10589:2002 and adapted for Internet use (with TCP/IP) as RFC 1142.

See also


  1. ^ Hubert Zimmermann (April 1980). "OSI Reference Model—The ISO Model of Architecture for Open Systems Interconnection". IEEE Transactions on Communications 28 (4): 425–432.  
  2. ^ a b c Andrew S. Tanenbaum, Computer Networks, § 1.4.4.

Further reading

  • John Day, "Patterns in Network Architecture: A Return to Fundamentals" (Prentice Hall 2007, ISBN 978-0-13-225242-3)
  • Marshall Rose, The Open Book (Prentice-Hall, Englewood Cliffs, 1990)
  • David M. Piscitello, A. Lyman Chapin, Open Systems Networking (Addison-Wesley, Reading, 1993)
  • Andrew S. Tanenbaum, Computer Networks, 4th Edition, (Prentice-Hall, 2002) ISBN 0-13-066102-3
  • Gary Dickson; Alan Lloyd (July 1992). Open Systems Interconnection/Computer Communications Standards and Gossip Explained. Prentice-Hall.  

External links

  • ISO/IEC 7498-1:1994, Information technology—Open Systems Interconnection—Basic Reference Model: The Basic Model
  • ITU-T Recommendation X.200 (11/93) [ISO/IEC 7498-1:1994], Open Systems Interconnection - Basic Reference Model.
  • Open System Interconnection
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.