Charter of the Efficient XML Interchange Working Group
The Efficient XML Interchange Working Group is part of the W3C XML Activity and follows the Working Group
process described in section 6.2
Working Groups and Interest Groups of the W3C Process Document.
Table of Contents
- Mission
- Scope and Goals
- Out of scope
- Success criteria
- Deliverables and duration
- Expected milestones
- Coordination with Other Groups
- Working Group participation
- Meetings
- Communication
- Confidentiality
- Patent Policy
Mission
The main objective of the Efficient XML Interchange (EXI) Working Group is to develop a
format that allows efficient interchange of the XML Information Set, based on
the conclusions of
the XML Binary Characterization Working Group.
Scope and Goals
XML has been enormously successful as a markup language for documents and
data, but is not an optimal format for all purposes. The XML Binary
Characterization Working Group established a set of use cases for which XML
employment may be problematic. The Efficient XML Interchange Working Group is
chartered to define an alternative encoding of the XML Information
Set that addresses at least the minimum
requirements identified by the XML Binary Characterization Working
Group. The Working Group shall also consider properties that shouldn't
be prevented, as listed in the second list of the decision tree.
Such support will be considered as extensions to the XML Information
Set or extensions introduced in the XML Schema 1.0
Post–Schema–Validation Infoset and in the XQuery 1.0
and XPath 2.0 data model.
The goals of this Working Group are:
- Fulfill the design
goals of XML with the following exceptions:
- The interchange format must be compatible with the XML Information
Set instead of being “compatible with SGML” (XML goal
3);
- For performance reasons, the format is not required to be
“human–legible and reasonably clear” (XML goal
6);
- Terseness in efficient interchange is important (XML Goal 10).
- Address all requirements
and use cases from the
XML Binary Characterization Working Group;
- Maintaining the existing interoperability between XML applications, as
well as XML specifications;
- Establish sufficient confidence in the proposed format, in particular
establishing confidence that the performance gains are significant, and the
potential for disruption to existing processors is small;
The Working Group will start by considering existing solutions and will
evaluate each in terms of implementability and performance against the
requirements and use cases documents produced by the XML Binary
Characterization Working Group.
Out of scope
This Working Group is not chartered to:
- Introduce a new data model for XML;
- Develop an application specific format. Like XML itself, the new format
must support a wide variety of applications.
Success criteria
Two of the entrance criteria used for the Last Call phase were:
- the Working Group Note on the impact of the new format on existing XML
technologies;
- the Working Group Note analyzing the performance gains of the new format,
based on the criteria included in the measurement methodologies
document. For example, in the case of compactness,
the information compression is expected to be at most 20% larger than its
equivalent ASN.1 PER, when a schema optimization is in use. Some of the
analysis require to have an implementation and will be done during the
Candidate Recommendation phase, such as processing efficiency.
Two of the entrance criteria used for the Proposed Recommendation phase will
be:
- demonstrate the performance gains of the new format, based on the prior
analysis done as an entrance criteria of the Last Call phase. In addition,
an analysis regarding the properties that need an implementation to be
evaluated, such as processing efficiency, will be conducted.
- demonstrate at least two interoperable implementations supporting all the
features provided in the specification. One of the implementations must be
available for public use.
The Working Group may at any stage recommend the use of an already published
format, provided that it satisfies the above criteria, instead of providing a
W3C Recommendation.
Deliverables and duration
Deliverables
The Working Group is expected to produce:
- A W3C Working Group Note, providing an analysis of the
performance measurements using the measurement methodologies
document, and performance gains. The analysis should use a wide
range of sizes and complexity in XML input documents, representing at least
each of the use cases.
Favorable performance results will help build community support by
illustrating the advantages that some applications may gain with this
format over ordinary XML text streams.
- A Test Suite and corpus of measurable documents which can demonstrate the
results described in the performance measurements Note.
- A W3C Working Group Note, providing an analysis of the new
format’s impact on existing XML technologies — in
particular XML Canonicalization, XML Signature, and XML Encryption —
and processors.
- A W3C Recommendation for efficient XML interchange.
Duration
The expiration date of this charter is 31 January 2010.
Charter update history:
* On 16 February 2010 this charter was extended until 30 September 2010.
Expected milestones
The following milestones are proposed. As usual, the duration of the review
period must be negotiated with other groups.
- January 2009
- Candidate Recommendation.
- June 2009
- Proposed Recommendation, along with the final analysis of the
performance gains, based on implementation reports.
- September 2009
- Recommendation.
Coordination with Other Groups
W3C Groups
The Working Group should coordinate its efforts with W3C Working Groups, in
particular in the XML Activity as well as the Technical Architecture Group.
External Groups
- BiM, ISO/IEC 23001-1:2006
- Binary MPEG format for XML or BiM, provides a standardized set of
generic technologies for encoding XML documents. It addresses a broad
spectrum of applications and requirements by providing generic methods
for transmitting and compressing XML documents. Recently two amendments
AMD 1:2007 ("Conformance and reference software") and AMD 2:2008
("Conservation of prefixes and extensions on encoding of wild cards")
have been issued.
- ISO/IEC/ITU-T
- Fast Infoset (ITU-T Rec. X.891 (2005) | ISO/IEC 24824-1) is in the
process of being approved within the ISO.
- OMA
- Open Mobile Alliance (OMA) develops standards for mobile device
industry. Specifications such as OMA Device Management use XML and are
designed with sensitivity to implementation foot-print and communication
bandwidth.
- Web3D
- The Web3D Consortium continues to
participate in the EXI working group. Web3D intends to upgrade the
Extensible 3D (X3D) Graphics Specification Compressed Binary Encoding
(CBE) from utilizing Fast Infoset (FI) to EXI, once EXI becomes a W3C
Recommendation.
Working Group participation
Effective participation is expected to consume one workday per week for each
Working Group participant; two days per week for editors. The Chair shall
ensure that the criteria for Good
Standing are understood and followed.
To be successful, we expect the Working Group to have 10 or more active
participants for its duration.
Chair
The initial chairs of this Working Group are Michael Cokus (MITRE
Corporation), and Takuki Kamiya (Fujitsu).
W3C Team resources
The initial W3C Team
contact is Carine Bournez, with Liam Quin as a backup. It is expected that
this Working Group will consume up to 0.35 FTE, including administrative logistics.
Meetings
The Working Group will have distributed meetings, one to two hours every
week, and face–to–face meetings, every three or four months.
Communication
The Working Group will utilize a W3C Member mailing list, member-exi-wg@w3.org.
Confidentiality
The proceedings of this Working Group are Member-only,
subject to exceptions made by the Chair, after consultation with the Working
Group.
Patent Policy
This Working Group operates under the W3C Patent
Policy (5 February 2004 Version). To promote the widest adoption of Web
standards, W3C seeks to issue Recommendations that can be implemented,
according to this policy, on a Royalty–Free basis.
Liam Quin, XML Activity Lead
Carine Bournez, Team contact
Last modified $ Date: 2005/09/29 19:06:49 $