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External Data Representation: Difference between revisions

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==External links==
==External links==
The XDR standard exists in three different versions in the following RFC's...
The XDR standard exists in three different versions in the following RFC's...
* [http://www.rfc-editor.org/rfc/rfc4506.txt RFC 4506] 2006 Probably the current version.
* [http://www.rfc-editor.org/rfc/rfc4506.txt RFC 4506] 2006 This document makes no technical changes to RFC 1832 and is published for the purposes of noting IANA considerations, augmenting security considerations, and distinguishing normative from informativereferences..
* [http://www.ietf.org/rfc/rfc1832.txt RFC 1832]1995 Probably the more widely implemented version.
* [http://www.ietf.org/rfc/rfc1832.txt RFC 1832] 1995 version.
* [http://www.faqs.org/rfcs/rfc1014.html RFC 1014] 1987 Probably the original version.
* [http://www.faqs.org/rfcs/rfc1014.html RFC 1014] 1987 version.


*[http://lxr.mozilla.org/seamonkey/source/js/src/jsxdrapi.c jsxdrapi.c], the main source file of SpiderMonkey that uses XDR
*[http://lxr.mozilla.org/seamonkey/source/js/src/jsxdrapi.c jsxdrapi.c], the main source file of SpiderMonkey that uses XDR

Revision as of 22:45, 8 September 2008

eXternal Data Representation (XDR) is an IETF standard from 1995 of the presentation layer in the OSI model. XDR allows data to be wrapped in an architecture independent manner so data can be transferred between heterogeneous computer systems. Converting from the local representation to XDR is called encoding. Converting from XDR to the local representation is called decoding. XDR is implemented as a software library of functions that is portable between different operating systems and is also independent of the transport layer.

The XDR data format is in use by many systems, including:

XDR data types

  • boolean
  • char (8 bit integer/character)
  • int (32 bit integer)
  • hyper (64 bit integer)
  • float
  • double
  • enumeration
  • structure
  • string
  • fixed length array
  • variable length array
  • union
  • opaque data
  • Optional data. It is notated similarly to C pointers, but is represented as the data type "pointed to" with a boolean "present or not" flag.

See also

The XDR standard exists in three different versions in the following RFC's...

  • RFC 4506 2006 This document makes no technical changes to RFC 1832 and is published for the purposes of noting IANA considerations, augmenting security considerations, and distinguishing normative from informativereferences..
  • RFC 1832 1995 version.
  • RFC 1014 1987 version.