Note: This information is out-of-date, but is kept for historical and archival reasons.

Areas of Consortium Activity

September 1994

The goal of the World Wide Web Consortium (W3C) will be to ensure the evolution of the World Wide Web (W3) protocols into a true information infrastructure in such a fashion that smooth transitions will be assured both now and in the future.

Toward this goal, the MIT Consortium team will develop, support, test, disseminate W3 protocols and reference implementations of such protocols and be a vendor-neutral convenor of the community developing W3 products. In this latter role, the team will act as a coordinator for W3 development to ensure maximum possible standardization and interoperability.

The W3C Director in consultation with the Advisory Committee will more fully define the priorities and activities of the Consortium. Therefore, the work described herein is a starting point and also what we perceive to be important to the evolution of the Web. The technical part of the work falls into the following broad categories:

Automatability: The ability to replace frequently used manual procedures with automated ones.
Extensibility: The ability for new ideas, concepts, operations and object types to be incorporated into the Web incrementally and with back-compatibility;
Scalability, Efficiency, and Robustness: The properties which maintain the operation of the Web in the face of changes in technology and in dramatic growth in size and usage;
Incorporation of Privacy,: Web mechanisms for employing means for the and Authentication privacy, data integrity and authentication required for commercial or confidential use.

The following gives an overview of the state of the art in these fields and the impact which W3C will have through incorporation of these improvements.

Protocol design areas

In more detail, the work will involve changes to the specifications and conventions which are used or selected by the Web along the following lines:

Network transfer protocols: HyperText Transfer Protocol (HTTP) , including protocols for enhancing the robustness of the Web (proxy servers, caching, replication, optimal request routing, etc.).

Data formats for hypertext, hypermedia, etc.: HyperText Markup Language (HTML), etc.

In most cases W3C will attempt to define W3 specifications in terms of existing standards. This involves an awareness of the state of the art with related developments such as:

The Object Management Group's CORBA proposals

Alternative underlying networks such as ATM, wireless, etc.

Specific work in areas which are not deemed central to the needs of the Web may be done subject to the availability of specific funding.

More details on areas of work in which we or our collaborators are already engaged, as of September 1994 are as follows.

Incorporation of Privacy, and Authentication

(Note: Parts of this document are out of date, having been written in the summer of 1994. A new activity list is available.)

There is a need for W3, and HTTP in particular, to provide the three basic forms of network security: authentication, message integrity, and privacy. There is work already done in this field, most notably by EIT but also at CERN to add security to the HTTP protocol in a manner similar to the PEM enhancements for electronic mail.

We have an informal agreement to work with EIT to ensure that the work results in a common standard for interoperability. Our guiding principles in this area will be:

A choice of encryption levels and technologies should be available to the user, communications between peers taking place using facilities common to the two sides;

A common software interface in the reference code to allow new or different encryption modules to be added or removed. This is particularly necessary given the different laws surrounding the distribution and use of encryption code in different countries. This work will take place in conjunction with the Security area of the Internet Engineering Task Force (IETF) whose GSS task force is working on an callable interface in this area.

Decoupling of the key distribution and certificate verification system from the encryption itself. This is necessary because the key distribution system has social implications on the trust structure in the organizations which use it. We propose to implement a decentralized certificate system using the Web as a certificate repository: however, other systems could also be used.

We expect to provide at least one combination of facilities which will allow international communication, using technology which is available in some form both in the US and the EU. The basic forms of security, privacy and authentication will be adequate for transactions which involve payment, but further investigation will be necessary in order to determine the most appropriate approaches that will allow easy payment for information and for goods and services.

Enhanced document description languages

There is a need for more sophisticated document description languages than the basic HTML which is the lingua franca of the Web today. The basic Web architecture provides a method for negotiating formats, but some work to select or provide common standards in this are is necessary. The areas which are currently under development are:

Enhancements to HTML to allow more sophisticated documents, while preserving the principle of a format-independent transfer language. The details of this are available in the discussion notes of the HTML working group of the IETF and the www-html mailing list and in the repository of background materials. The features being prototyped and defined include tables, figures, and mathematical formulas.

A language for defining style, for mapping format-independent documents onto specific renderings;

The selection or definition of completely presentation-oriented languages such as Adobe Inc.'s "PDF" language, and the hyper-TeX and hyper-DVI languages;

Languages for 2, 3 and 4 dimensional compositional graphics, leading to distributed virtual reality. There are a number of contenders for such languages, but there is clearly some design work to be done before we have what we need here, as we are talking about merging the time and structure-based compositional features of HyTime with for example 3D graphics which has its own set of conventional notations. Current priorities are pushing HTML enhancements. For instance, there is a requirement from industry to define the current HTML more precisely. Future HTML enhancements are then organized in a series of levels.

Web semantics

The longer term goal is a much richer semantic web for automatability via agents. In the short term there is a requirement for the specification and demonstration of a number of features which may be implemented cleanly using HTML and HTTP's link typing capabilities. This will permit definition of large structured documents, and relationships between versions and translations of documents to be specified by servers in a way that will allow clients to give simple user access to these properties, using for example toolbars and graphical maps.

Some link relationships have been specified for a while, but few have been in widespread use. The consortium will prototype the use of more link types, whose adoption as common practice will lead to a more readable web.

A second area in which semantics can be included is in the design of semantically rich formats for alternative representations of objects. This work is in the research stage, and involves elaboration of any extensions or generalizations to be made to the W3 hypertext model.

Protocol support for interaction

Work is in progress at CERN to provide support for user interaction with the Web, such as direct editing and creation of new resources. This is needed to allow easier updates of the Web by people with the authority and knowledge to effect such changes.

Hypertext electronic mail, news and Notes-like collaborative services will need support editing facilities for HTTP. We will attempt to develop a common model so such protocols will be useful along a spectrum of such services. This in turn gives us a base for the use of the Web as a collaborative tool rather than a medium for centralized dissemination.

The HTTP protocol needs extensions for the update and creation of objects, so that for example an HTTP proxy can perform mail and news functions as an intermediary between for example an NNTP server and an HTTP client.

Scalability

There is a clear need for more sophisticated protocol features than HTTP currently provides to enable intelligent replication of information which is in wide demand. Features to control caching include the exchange of sufficient usage information to allow an efficient adaptive caching strategy, and also the exchange of logging, charging and intellectual property rights information to allow distribution through the network of caches to have the same capabilities as a simple client-server system.

A particular task is to incrementally add features to HTTP to allow caching features to be extended, along with modeling and algorithms work to provide a theoretical basis for the longer term.

Protocol Support

W3C will produce basic software which may be used as a reference implementation of the protocols. The following features are some example target developments of the protocol support code. The wish lists for the distributed reference implementations are constantly changing, as ideas move from conception to implementation in the code. The current state is kept on the Web. Much of the work of the consortium is expected to involve the folding into these products of contributions from members or from collaborating institutes.

The three basic reference implementations which the W3 Consortium will provide are the libwww common library, and a reference client and server implementation.

Common code library

The "libwww" code library contains code for the parsing and generation of all web-common data formats, and for the handling of the client side of all web-common protocols. It is structured in a very modular fashion, so that it may be used in whole or in part. Written for portability in a form of C which will compile under traditional K&R C compilers or under ANSI C, it nevertheless uses an object-oriented design style.

The library was designed for use in any application requiring access to the Web. It has been used not only in many clients, but also in servers which provide gateway web access. The libwww software released by the consortium will be a continuation of the releases which have been sourced from and evolved by CERN since the birth of the Web.

A planned work item will introduce a multi-threaded event driven code architecture. This will allow client implementations which can perform many network operations at once (even within the same thread or process), and easier porting between platforms. It will allow a good match with event-driven environments, such as Mac, Widows and X.

Reference server

The HTTP Daemon (HTTPD) server supports Unix- and VMS-based W3 hypermedia databases. It has allowed the W3 development team to experiment with new protocol features, and allowed many information providers to get information on-line rapidly and easily. Despite the fact that many servers have been produced for specific application needs, or platforms, the HTTPD server code will continue to be an important Web reference.

Prototype client

The consortium will produce one or more reference clients which may be used to prototype new libwww and protocol features.

A possible task in this area is to break out the HTML display widget as a common piece of code, taking the boundary of the common code up a level from its previous interface.

The consortium will work toward fully interactive clients, with wysiwyg editing facilities.

Test suites

Regression testing, and the generation of automatic test suites from protocol definition files will be done wherever possible. The extent to which these techniques can be used will have to be learned from experience and will depend on the cleanliness of the specifications. Test material and test programs will be made available as a reference code of the consortium.

Development Coordination

An activity inseparable from the protocol specification is the coordination among groups developing the Web. As interworking is essential to the concept of the Web, any aspects of client or server software which have implement protocols must have compatible or unique implementations. Competitive commercial software products require and assume common protocols. This project will help coordinate industrial and academic development activities so as to make greater use of resources, and reach higher functionality. Examples of this activity include:

The management of mailing lists for those interested in particular fields, and the classification of announcements;

The organization will conduct meetings as necessary.

The project will attempt to make exemplary use of the Web itself for these purposes, requiring development of extended functionality where needed.

Dissemination, promotion, and User support

While knowledge of the existence of W3 is becoming ubiquitous, a reference point is essential to ensure that misunderstandings do not arise, and to allow those in all sectors to keep abreast of developments. The project will seek to maintain:

Pointers to methods for getting access to the Web;

On the Web, a certain amount of non-technical information including answers to frequently asked questions;

Details of software and documentation available from the project, and pointers to the registry of software and services (below).

Registration and coordination of services

In order to provide a realistic picture of the deployment of the Web, W3C will maintain registries of:

Facilities offered on the Web by subject area

Suppliers of services and products for Web user

The administration of this information is in most cases delegated hierarchically. This information is not designed to compete with commercial catalogues, but will attempt to be as definitive as possible.

TimBL, Sept94, Mar95