Gen2 seeks to provide VISS functionality with the addition of:
- HTTPS transport
- Clearer access restriction model
- Query mechanism with support for basic operations
- VSS improvements
See also open source implementation
- VSS 2.0 as the recommended data model, and used in all spec examples.
- Support for subscribe over the transport WS.
- Support for the following over the transports HTTP and Web Sockets:
- get/set requests
- Service discovery
- Access restriction model based on JWT
- Search via query
- Subscription notification flow control via query
- VSS additions:
- Separation of node type and data type.
- Inclusion of attribute type nodes in the same branches as other node types.
- Instantiation support.
- Access restriction:
- Some details not fully defined: VSS properties, and fields in token.
- VSS versioning:
- A proposal by Gunnar accepted and implemented in VSS. Needed by both VISS and Gen2
- Some details not fully defined: syntax of comparison operators
- could relate to sampling methodologies etc
Topics for a Gen3 or extensions to Gen2
- Dynamic registration:
- A proposal by Ulf available, but no decision yet.
- Push/Pull optimization
- incorporating sampling methodologies in service subscription, eg Curve algorithm, time interval, event driven
- compression, serialization and alternate formats (separate agenda item later this week)
Areas of specifications in need of further attention.
- minor improvements needed. TG and PW reviewed, TG to propose wording before First Public Working Draft
- Data model:
- Dynamic registry chapter basically empty.
- If VSS not to be repeated here, but rather referenced to, no work needed. TG and PW reviewed, TG to propose wording based on VISS and group agreement on supporting alternate taxonomies
- Formal chapters - Conformance, Terminology, References (UB requests review of this chapter), ..:
- Needs work.
- Update needed. TG and PW reviewed, TG to propose wording changes
- Transport common defs:
- Transport protocols: Done by UB
- Only contains example payloads, everything else is missing.
- Formal chapters - Conformance, Terminology, References, ..:
- Needs work.
Out of Scope
Under discussion but not in current scope:
- Clustering, grouping of signals.
- Distributed server. (Mechanism to handle it available in Ulfs dynamic registry proposal)
- Other payload encoding than JSON
- Support for other transport protocols than HTTPS and WSS.