Tech Industry

W3C proposes HTTP overhaul

The World Wide Web Consortium proposes, in four working drafts and one note, an overhaul of the current hypertext transfer protocol, or HTTP.

In an attempt to simplify and speed the flow of information over the Web, the World Wide Web Consortium proposed an overhaul of the current hypertext transfer protocol, or HTTP.

The W3C released four working drafts and one note detailing its proposed protocol, dubbed HTTP-NG (for "next generation"). Begun a little over a year ago, HTTP-NG is the consortium's second proposal of an HTTP 1.0 revision; a draft for HTTP 1.1 cleared the W3C in January 1997 and now is under review by the Internet Engineering Task Force (IETF), which also will review HTTP-NG.

HTTP--familiar to Web users as the opening of most Web addresses--governs aspects of Web information flow from the most basic point-and-click interface design to how client and server computers exchange Web pages and files over the Internet.

The main advance of the HTTP-NG initiative over its predecessors is that it divides the work of HTTP from one comprehensive and complicated architecture into three simpler distinct parts.

One way to imagine the proposed protocol, suggested W3C research engineer Henrik Frystyk Nielsen, is as an information packaging factory composed of three floors. At the top floor, clients select information and perform actions through the point-and-click interface. On the middle floor, that information is put into the packets in which it will travel over the Internet. On the bottom floor, those packets are sent out over the Net, and packets containing client requests are received.

A central task of HTTP, the fundamental Web protocol, is to work in conjunction with TCP/IP, the fundamental Internet protocol. Making HTTP run smoothly on top of TCP/IP is the goal of the HTTP-NG factory's bottom level, which is called SMUX (pronounced "ess-mucks").

Under HTTP 1.0, most times that a user requests a page, file, or action, the client must make a new connection to the server over the Internet via TCP/IP. SMUX, by contrast, would establish a "persistent connection" between client and server for the duration of a user's visit to that Web site, much like a telephone connection lasts uninterrupted for the length of a conversation.

The key to SMUX is a method of information transport called multiplexing, which, to pursue the telephone analogy, lets the conversation flow in both directions simultaneously.

The HTTP 1.1 proposal also provided for persistent connections, but HTTP-NG rectifies a number of deficiencies in that version, according to the W3C.

The middle floor of the HTTP-NG factory runs on the Binary Wire Protocol, which specifies how bytes of information are packetized and prepared for transport over the Net.

The top floor, where the means of user interaction are established, is called the Web Interfaces Specification. This proposed specification lets computers know how to respond not only to basic commands such as clicking on a hyperlink, but also how to manage more complex interactions having to do with buying and selling products, software downloads, home banking, and the like.

A fourth draft put out by the W3C last week is for the Architectural Model Specification. This proposal details the structure of the three-pronged protocol. Lastly, the W3C put out a note describing the aims and contours of the HTTP-NG initiative as a whole.

Nielsen, who is the consortium's HTTP-NG activity leader, said the proposed drafts could go a long way toward unclogging an increasingly congested World Wide Web.

"The purpose of these proposals is to make the Web protocol simpler, to speed up the Web, to make it more robust and reliable," Nielsen said. "If I have a new service to sell lawn mowers on the Web, for example, we want to be able to do things so that all the required applications can deal with the task in an automated way. The goal is to make the protocol simple, efficient, robust, and extensible."

The IETF is expected to consider the HTTP-NG proposals at its August meeting in Chicago.