The story of content negotiation does not end with the Accept and Content headers, for a couple of reasons:

·         Content negotiation in HTTP incurs some performance limits. Searching through many variants for appropriate content, or trying to "guess" the best match, can be costly. Are there ways to streamline and focus the content-negotiation protocol? RFCs 2295 and 2296 attempt to address this question for transparent HTTP content negotiation.

·         HTTP is not the only protocol that needs to do content negotiation. Streaming media and fax are two other examples where client and server need to discuss the best answer to the client's request. Can a general content-negotiation protocol be developed on top of TCP/IP application protocols? The Content Negotiation Working Group was formed to tackle this question. The group is now closed, but it contributed several RFCs. See the next section for a link to the group's web site.

 


Hypertext Transfer Protocol (HTTP)