Coloured Book protocols

The Coloured Book protocols were a set of communication protocols for computer networks developed in the United Kingdom in the 1970s. The name originated with each protocol being identified by the colour of the cover of its specification document. The protocols were in use until the 1990s when the Internet protocol suite came into widespread use.


First defined in 1975,[1] they evolved through experience with the Experimental Packet Switched Service run by Post Office Telecommunications beginning in 1977. They were used on the SERCnet from 1980,[2] which became the JANET academic network from 1984. The protocols gained some acceptance internationally as the first complete X.25 standard,[1][3] and gave the UK "several years lead over other countries".[4]

From late 1991, Internet protocols were adopted on the Janet network instead; they were operated simultaneously for a while, until X.25 support was phased out entirely in August 1997.[5][6]


The standards were defined in documents identified by the colour of the cover:[1][3][7]

The Pink BookEdit

The Pink Book defined protocols for transport over Ethernet. The protocol was basically X.25 level 3 running over LLC2.

The Orange BookEdit

The Orange Book defined protocols for transport over local networks using the Cambridge Ring (computer network).

The Yellow BookEdit

The Yellow Book defined the Yellow Book Transport Service (YBTS) protocol, also known as Network Independent Transport Service (NITS), which was mainly run over X.25. It was developed by the Data Communications Protocols Unit of the Department of Industry in the late 1970s. It could also run over TCP.[8] The Simple Mail Transfer Protocol was extended to allow running over NITS.[9]

The Yellow Book Transport Service was somewhat misnamed, as it does not fulfill the Transport role in the OSI 7-layer model. It really occupies the top of the Network layer, making up for X.25's lack of NSAP addressing at the time, which didn't appear until the X.25 (1980) revision, and wasn't available in implementations for some years afterwards. YBTS used source routing addressing between YBTS nodes—there was no global addressing scheme at that time.

The Green BookEdit

The Green Book defined two protocols to connect terminals across a network: an early version of what became Triple-X PAD running over X.25, and the TS29 protocol modelled on Triple-X PAD, but running over YBTS. It was developed by Post Office Telecommunications. These protocols are similar in functionality to TELNET.

The Fawn BookEdit

The Fawn Book defined the Simple Screen Management Protocol (SSMP)

The Blue BookEdit

The Blue Book defined the Network-Independent File Transfer Protocol (NIFTP), analogous to Internet FTP, running over YBTS. Unlike Internet FTP, NIFTP was intended for batch mode rather than interactive usage.

The Grey BookEdit

The Grey Book defined protocols for e-mail transfer (not file transfer as is sometimes claimed), running over Blue Book FTP.

The Red BookEdit

The Red Book defined the Job Transfer and Manipulation Protocol (JTMP), a mechanism for jobs to be transferred from one computer to another, and for the output to be returned to the originating (or another) computer, running over Blue Book FTP.

Naming schemeEdit

One famous quirk of Coloured Book was that components of hostnames used reverse domain name notation as compared to the Internet standard. For example, an address might be user@UK.AC.HATFIELD.STAR instead of[2][10][11][12]

See alsoEdit


  1. ^ a b c Davies, Howard; Bressan, Beatrice (2010-04-26). A History of International Research Networking: The People who Made it Happen. John Wiley & Sons. pp. 2–3. ISBN 978-3-527-32710-2.
  2. ^ a b "6th UK Network Operators' Forum Meeting Agenda". Retrieved 2020-02-12. See "15:00 Starting the Commercial Internet in the UK (Peter Houlder)"
  3. ^ a b Earnshaw, Rae; Vince, John (2007-09-20). Digital Convergence - Libraries of the Future. Springer Science & Business Media. p. 42. ISBN 978-1-84628-903-3.
  4. ^ "FLAGSHIP". Central Computing Department Newsletter (12). January 1991. Archived from the original on 2020-02-13. Retrieved 2020-02-13.
  5. ^ "FLAGSHIP". Central Computing Department Newsletter (16). September 1991. Archived from the original on 2020-02-13. Retrieved 2020-02-13.
  6. ^ "Janet(UK) Quarterly Report to the Janet Community: July 1997 to September 1997". Janet webarchive. 1997. Archived from the original on February 16, 2012.
  7. ^ Rutter, Dorian (2005). From Diversity to Convergence: British Computer Networks and the Internet, 1970-1995 (PDF) (Computer Science thesis). The University of Warwick.
  8. ^ C. J. Bennett (12 August 1980). "The Yellow Book Transport Service: Principles and Status".
  9. ^ Jon Postel (August 1982). Simple Mail Transfer Protocol. IETF. sec. C. doi:10.17487/RFC0821. RFC 821.
  10. ^ Mansell, Robin; Mansell, Dixons Chair in New Media and the Internet Interdepartmental Programme in Media and Communications Robin (2002). Inside the Communication Revolution: Evolving Patterns of Social and Technical Interaction. Oxford University Press. p. 208. ISBN 978-0-19-829656-0.
  11. ^ Reid, Jim (2007-04-03). "The Good Old Days: Networking in UK Academia ~25 Years Ago" (PDF). UKNOF7. Manchester. Retrieved 2008-04-16.
  12. ^ The "Hidden" Prehistory of European Research Networking. Trafford Publishing. ISBN 978-1-4669-3935-6.


  • A Dictionary of Computing. Oxford University Press, 2004, s.v. "coloured book"

External linksEdit