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Team Comment on the Tentative Hold Protocol Submission

W3C is pleased to receive the Tentative Hold Protocol Submission from Intel.

As Web services emerge, there is a need for aggregating several services and interacting with different businesses. The Tentative Hold Protocol defines an architecture that allows tentative, non-blocking holds or reservations in order to facilitate coordination of multi-business transactions.

The protocol consists of a set of operations (hold request by the client, hold cancellation by the client or the resource provider, etc), in order to place reservations prior to commitment (e.g. purchase of a vacation package) on a set of needed resources. By using this mechanism, clients can have a global knowledge of all the resources available to them before making a decision, while providers can provide non-blocking reservations to several clients, keeping control of their resources.

The protocol is described by a white paper and by a technical specification; the protocol is described with a WSDL 1.1 definition and a set of examples, and the specification also lists a set of requirements for implementations.

Tentative Hold Protocol relates to the following W3C Activities and events:

XML Schema

The structure of the resource specific information carried by the protocol (e.g. product identifier, description, quantity, ...) as well as protocol headers are described and validated using XML Schema.

XML Protocol

Communications between clients and resource providers are done in the form of messages encoded in XML. The XML Protocol Working Group is developing an XML-based protocol, SOAP Version 1.2, which can be used to carry Tentative Hold Protocol messages. Examples of use of the Tentative Hold Protocol with the SOAP/1.1 protocol, on which the XML Protocol Working Group is basing its work, are given.

Workshop on Web services

Aggregation of Web services is a theme which was discussed at the Web services workshop.

In order to fit plainly in the Web architecture and fulfill its automation role, the Tentative Hold Protocol should mandate use of URIs in order to identify target recipient and resources in its headers; the replyTo element currently allows other kind of identifiers, the holdId element requires UUID which could use the uuid: URI scheme or another type of URI.

One of the requirements of Tentative Hold Protocol implementations is to be able to communicate through firewalls. Although this requirement can only be fulfilled by the underlying protocol used to transfer Tentative Hold Protocol messages (e.g. SOAP Version 1.2 over HTTP), circumventing security mechanisms purposely should be avoided: the choice should be left to network security administrators to filter out particular types of traffic.

This protocol being oriented towards electronic commerce transactions, privacy is a primary concern and its use should probably be joint with the use of P3P.

Next Steps

The submission will be brought to the attention of the XML Protocol Working Group as a use case for the protocol they are designing.

The Semantic Web Activity includes an 'Advanced Development' component (SWAD) created to identify promising directions for Web automation technologies in advance of the consensus process. While the W3C SWAD effort is not currently investigating this area, the Submission will be considered when evaluating further areas for SWAD research.

Feedback on this technology is encouraged on the www-ws mailing list (public archive).

Disclaimer: Placing a Submission on a Working Group/Interest Group agenda does not imply endorsement by either the W3C Staff or the participants of the Working Group/Interest Group, nor does it guarantee that the Working Group/Interest Group will agree to take any specific action on a Submission.