1. A Standard Vocabulary for Delivery Context
Martin Jones
Volantis Systems

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. Capabilities & Preferences
The Missing Link?
CC/PP Example
Client
(User
Agent)
Origin
Server
Capabilities & Preferences
HTTP
CC/PP Exch.
RDF/XML
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 don’t be constrained by them