W3C Architecture Domain

XML Binary Characterization Working Group Charter

  1. Scope
  2. Deliverables and Schedule
  3. Relationships with Other Work
  4. Participation, Meetings, and Logistics
  5. W3C Staff Resource Commitment
  6. Patent Disclosures

Note: This charter has been modified on June 15, 2004. The Patent Policy section has been replaced by a Patent Disclosures section.


XML has been enormously successful as a markup language for documents and data; it enjoys wide support and deployment in a variety of programming languages, computing platforms, applications and specifications. In part, this is because it provides a single means of marking up data that isn't specific to any one application domain. This has encouraged the development of a number of generic tools (e.g., parsers, generators, APIs, validators, etc.) and standards (e.g., XPath, XML Schema, XML Query, etc.).

However, XML 1.x may not be the optimal format for all purposes. There are cases where the overhead of generating, parsing, transmitting, storing, or accessing XML-based data may be deemed too great for a particular application. As a result, some use cases' requirements may not be met by XML 1.x. There are a number of existing binary interchange mechanisms and formats that are used to address some or all of these needs.

The XML Binary Characterization Working Group is tasked with gathering information that will help determine the nature of these use cases, characterizing the properties that XML provides as well as those that are required by the use cases, and establishing objective, shared measurements to help judge whether XML 1.x and alternate (binary) encodings provide the required properties.

It is expected that the Working Group's products will be used to inform discussion about alternate encodings of XML 1.x. If the Working Group is able to agree on a set of properties that meets the requirements of those Use Cases deemed in-scope, it may use the Measurements Document to perform characterizations of various candidate technologies to ascertain that creating a serialization of XML with those properties is technically feasible.

The Working Group may be unable to agree upon a common set of properties that meets the requirements of those use cases deemed in-scope, or may be unable to identify any candidate technology that meets the stated these requirements. Additionally, the Working Group may determine that the benefits brought by an alternate encoding of XML may not be sufficient to justify the loss of interoperability incurred.

If the Working Group successfully identifies at least one candidate in this manner, it may suggest a charter for further work in this area.

Deliverables and Schedule

The XML Binary Characterization WG has the following deliverables:

Properties Document

The Properties document will determine the relevant properties of XML 1.x to provide a common understanding of the desirable characteristics of an alternate encoding, and the appropriate aspects to measure in candidate solutions. For example, the property of ordered children is often (but not always) significant, so that paragraphs in a transmitted XHTML document must be received in the correct order, but rows in a relational database dump might not have such a constraint, even when represented in XML.

The Properties document is expected to be published as a Working Group Note.

Use Cases Document

The Use Cases document will record relevant use cases to understand how XML 1.x is currently used, and what optimizations over XML 1.x are desirable and necessary. Each use case will be characterized in an agreed-upon format that identifies each of the relevant properties that apply, or may be sacrificed, to satisfy the use case.

The Use Cases document is expected to be published as a Working Group Note.

Measurements Document

The Measurements document will establish shared measurement methods for each property defined in the Properties document to help evaluate aspects of both XML and alternate encodings. It will be accompanied by a test corpus that will provide shared data on which to perform the measurements that it describes. The Measurements document should also include a template that can be used to characterize the measurements of an encoding candidate.

The Measurements document is expected to be published as a Working Group Note.

Characterizations Document

If the Working Group is able to agree upon a common set of properties that meet the requirements of the use cases deemed in-scope, it may record them in the Characterizations document and perform characterizations of candidate technologies submitted to the Working Group.

Charter Proposal

If the Working Group is able to identify at least one technology through characterization of an implementation with the measurements in the Measurements document, it may choose to suggest a charter for further work in this area.


These are subject to revision due to editorial needs and external scheduling issues; updates will be negotiated with the related groups and recorded on the XML Binary Characterization Working Group home page. Meeting dates are mentioned here for planning purposes. In order to keep to a schedule, it should be noted that the Working Group Chair has the authority to rule issues out of scope or to shelve them as necessary,

March 2004
Working Group formation.
May 2004
First Working Group face-to-face meeting.
July 2004
First Working Draft of the Use Cases document.
First Working Draft of the Properties document.
September 2004
First Working Draft of the Measurements document.
March 2005
Working Group ends.

The expected duration of the Working Group is 1 year, through 31 March 2005.

Relationship with Other Work

W3C Groups and Activities

XML and XML-derived activities have become a strategic technology in W3C and elsewhere. Each deliverable of any Working Group must satisfy the dependencies from other W3C Working Groups before it can advance to Candidate Recommendation.

Technical Architecture Group
The TAG is chartered to document and build consensus around principles of Web architecture and to interpret and clarify these principles when necessary. The XML Binary Characterization Working Group consult with the Technical Architecture Group regarding the properties of XML and refer issues to the TAG when necessary. The Working Group is also expected to provide feedback regarding issue binaryXML-30.
XML Activity
The XML Binary Characterization Working Group will interact with each Working Group in the XML Activity to review its deliverables.
Web Services Activity
Several stated use cases for alternate encoding of XML have been in the domain of Web services; it is expected that the Working Group will interact with the Web services activity to gather use cases and properties required by them.
DOM Activity
The DOM Activity represents one of the primary means of accessing and manipulating XML documents, and should be consulted by the Working Group.
QA Activity
The QA Activity is charged with the development of validators, test tools, and harnesses, and therefore should be consulted by the Working Group.
Scalable Vector Graphics Working Group
The SVG community has manifested interest for binary encoding and 3GPP has had liaisons with the SVG WG on this topic. Also, the SVG WG shares the XMLP WG's interest in packaging and binary payloads, two areas which a binary encoding is highly likely to cover.
Timed-Text Working Group
The TT WG has expressed strong interest in the field, and has concerns that are close to those of the broadcasting community which is already a consumer of binary infoset encodings.
Web Accessibility Initiative
The Working Group must cooperate with the Web Accessibility Initiative to ensure that binary infoset encodings requirements do no conflict with W3C accessibility goals.
Device Independence Working Group
The Working Group cooperates with this group to ensure that the requirements for binary infoset encodings meet the requirements for device independent access.
Internationalization Working Group
The Working Group cooperates with this group to ensure that the requirements for binary infoset encodings do not conflict with support for internationalization.

External Groups

The XML Binary Characterization Working Group should liaise with at least the following groups outside W3C:

3GPP has explicitly asked the W3C about binary formats, and has researched them itself.
Web3D has explicitly asked the W3C about binary formats, and has researched them itself.
MPEG-7 has an ISO standard binary infoset serialisation, BiM, and is currently working on a second version.
MPEG-4 is currently re-evaluating its BIFS encoding, and may be interested in providing input notably regarding efficient decoding on small devices.
A Joint Working Group of ISO and ITU-T is currently examining an alternate encoding of XML, based upon ASN.1.
The CCSDS has explicitly expressed strong interest in binary infoset serialisations.
The Open Mobile Alliance (which has subsumed the older WAP Forum) has done work in this area.

Participation, Meetings, and Logistics


Each participant should expect to spend one day per week on work for this Working Group, although the time commitment for the chair and editors may be higher.

In addition to the time commitment noted above, each participant of the WG may be expected to show evidence to the chairs of active work in the general topic area.

To join the XML Binary Characterization Working Group, please follow the instructions on the Working Group home page.

Group Home Page

The Working Group will have a group home page that records the history of the group, provides access to the archives, meeting minutes, task list and current documents, participants list, and other relevant documents and resources. It will be maintained by W3C Team contact in collaboration with the Chair.

The Working Group also has a public Home Page, maintained by the W3C Team contact in collaboration with the Chair.

Minutes of Working Group meetings shall be made available to members of the Working Group and archived in a location accessible to the W3C membership. The Chair will decide which issues, if any, are not made public.

Face-to-Face Meetings

Face-to-face meetings will be held as needed; it is expected that such meetings will be held about every two to three months.

The working group will use a member-only mailing list for technical communication, supplemented by a public list that may, at the discretion of the chair, be directed to discuss specific topics.


To be successful, we expect the Working Group to have approximately 15 to 20 active participants. A large public review group that will participate in the mailing list discussions is expected.

The XML Binary Characterization Working Group will initially be chaired by Robin Berjon of Expway. The initial W3C Team contacts are Carine Bournez and Liam Quin.

W3C Staff Resource Commitment

The W3C Team is responsible for the mailing lists, for the public Working Group pages, and for liaison with the W3C Communications Team for the publication of working drafts. W3C Team members are expected to adopt the same requirements for meeting attendance, timely response, and information disclosure as are required of W3C Members. This WG is expected to need approximately 35% of the time of one Team member.

Patent Disclosures

The XML Binary Characterization Working Group provides an opportunity to share perspectives on XML Binary Characterization in general. W3C reminds Working Group participants of their obligation to comply with patent disclosure obligations as set out in Section 6 of the W3C Patent Policy. While the Working Group does not produce Recommendation-track documents, when Working Group participants review Recommendation-track specifications from other Working Groups, the patent disclosure obligations do apply.

Liam Quin, W3C XML Activity Lead

Last Modified: $Date: 2004/06/15 17:43:56 $