RFC 2296 (rfc2296) - Page 2 of 13
HTTP Remote Variant Selection Algorithm -- RVSA/1
Alternative Format: Original Text Document
RFC 2296 HTTP RVSA/1.0 March 1998
5 Security and privacy considerations.......................11
6 Acknowledgments...........................................12
7 References................................................12
8 Authors' Addresses........................................12
9 Full Copyright Statement..................................13
1 Introduction
HTTP allows web site authors to put multiple versions (variants) of
the same information under a single URL. Transparent content
negotiation [2] is a mechanism for automatically selecting the best
variant when the URL is accessed. A remote variant selection
algorithm can be used by a HTTP server to choose a best variant on
behalf of a negotiating user agent. The use of a remote algorithm
can speed up the transparent negotiation process by eliminating a
request-response round trip.
This document defines the remote variant selection algorithm with the
version number 1.0. The algorithm computes whether the Accept-
headers in the request contain sufficient information to allow a
choice, and if so, which variant must be chosen.
2 Terminology and notation
This specification uses the terminology and notation of the HTTP
transparent content negotiation specification [2].
3 The remote variant selection algorithm
This section defines the remote variant selection algorithm with the
version number 1.0. To implement this definition, a server MAY run
any algorithm which gives equal results.
Note: According to [2], servers are always free to return a list
response instead of running a remote algorithm. Therefore,
whenever a server may run a remote algorithm, it may also run a
partial implementation of the algorithm, provided that the partial
implementation always returns List_response when it cannot compute
the real result.
3.1 Input
The algorithm is always run for a particular request on a
particular transparently negotiable resource. It takes the
following information as input.
1. The variant list of the resource, as present in the Alternates
header of the resource.
Holtman & Mutz Experimental