WWW6: HyperText Transfer protocol (HTTP) V1.1

jim gettys from Digital Equipment Corporation and member of the W3C's architecture domain presented the status of V1.1 of the HyperText Transfer Protocol. HTTP V1.1, together with Cascading Style Sheets (CSS V1.0) and Portable Network Graphics (PNG) can speed up data transfer up to the factor eight !
performance measurements where done using the Microscape homepage, a combination of Microsoft's and Netscape's homepage. for details, see this note.

first jim explained some of the problems with HTTP V1.0

• it is a quite verbose protocol with many roundtrips. this results in many TCP/IP packets with relatively few information passed back and forth.
• because it is a stateless protocol and passes only one URL at a time, it requires many opens and closes on the server.
• the caching model is poor and unreliable and therefore rarely used.
• browsers started to open multiple connections which may result in self-congestion.

HTTP V1.1 is now a proposed standard. its main goal is to reduce the load on the Internet caused by HTTP. it shall become a "well behaved" protocol. due to the heavy load the Web introduced on the Internet, it was important to come up with a solution as fast as possible. HTTP V1.1 it is as backward compatible with V1.0 as possible.

some of the issues deferred to the future include further improvements in the caching model, compression, multiplexing, transparent content negotiation and protocol extension negotiation (PEP). in the far future, HTTP needs to be replaced with a more efficient protocol. the transition to a new protocol is another open topic.

HTTP V1.1 should help to increase the performance on the Web, to reduce the load on Web servers as well as on the Internet and to improve the reliability of caching applications.
new features include:

• HOST: header now required in any request (this is actually already implemented in most browsers)
• RANGE: header allows a browser to request only part of a document (already implemented in the common browsers, such as MSIE and Netscape).
• more reliable caching and the introduction of an AGE: value to be maintained by the caches along the path to track the age of a document in the cache.
• new methods: DELETE, OPTIONS, PUT, TRACE and UPGRADE.
• persistent connections to provide a major performance gain.

the slides of jim's presentation are available on the Web.

the W3C provides further information about protocols, a performance report about HTTP V1.1 and Jigsaw, an HTTP daemon written in Java which supports HTTP V1.1

to the WWW6 trip report main document