Martin Jones

1
A Standard Vocabulary for Delivery Context

• Martin Jones
• Volantis Systems
• martin.jones_at_volantis.com

2
A Standard Core Vocabulary

• Why do we need one?
• What characteristics should it have?
• What should it cover?
• What does this mean for the DIWG?

3
Observed Issues

• Evolving DI requirements are not being properly
  met by existing device identification techniques
• Disappointingly low usage of new delivery context
  mechanisms
• Chicken egg scenario vis-à-vis user agents and
  origin servers
• Potential for interoperability issues between
  implementations, resulting from vocabulary
  mismatch

4
The Missing Link?

• CC/PP Example

Client (User Agent)
Origin Server
Standard Vocabulary
5
Existing Vocabularies

• Are domain-specific
• e.g. WAP UAProf
• Are not broad enough in scope to facilitate true
  context-aware presentation
• Provide inconsistent levels of detail
• Often weakly specified (too many MAYs)
• Are in danger of proliferating

6
Suggested properties of a standard vocabulary

• Comprehensive enough to cover the majority of
  needs
• Modular to allow irrelevant parts to be omitted
  safely from implementations
• Detailed at multiple levels to allow for simple
  or complex interpretations
• Extensible to allow for additions
• Balanced to provide good coverage in all
  relevant areas

7
Which areas should a standard vocabulary cover?

• User Agent capabilities
• Markup elements, CSS elements, content formats
  (more than just MIME content types), plug-ins
  supported/installed, size limits, security
• Device capabilities
• Input, output, identification, security,
  physical, ergonomic, add-on modules
• Network capabilities
• Bandwidth, latency, QoS, security, caching,
  adaptation
• User preferences
• Language, modality, accessibility, taste,
  speed/richness
• User environment
• Place, position, privacy, mood

8
What does this means for the work of the DIWG?

• Give as much focus to specifying a standard DC
  vocabulary as to the underlying exchange and
  negotiation mechanisms
• Try to reconcile and build on existing
  vocabularies but dont be constrained by them