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Subject: Minutes: XDI TC Telecon Friday 2012-12-07
- From: Drummond Reed <drummond.reed@xdi.org>
- To: OASIS - XDI TC <xdi@lists.oasis-open.org>
- Date: Sat, 8 Dec 2012 00:39:01 -0800
Following are the minutes of the unofficial telecon of the XDI TC at:
Date: Friday, 07 December 2012 USA
Time: 9:00AM - 10:30AM Pacific Time (16:00-17:30 UTC)
ATTENDING
Bill Barnhill
Phil Windley
Markus Sabadello
Drummond Reed
Joseph Boyle
GUESTS
Animesh Chowdhury
THE ETHERPAD LINK FOR TODAY IS:
***** NEWS & UPDATES *****
--- PROCESS PROPOSAL FROM BILL
We put this off until next week's call.
***** PRESENTATIONS/DISCUSSIONS *****
--- USING LINK CONTRACTS FOR EVENT CHANNEL AUTHORIZATION
Drummond presented an example of how XDI link contracts can be used to provide authorization and access control for event channels.
Bill suggested that the access control model we should reference is the IETF COPS-PR. In particular, this model should answer the questions:
- What acts as policy decision point?
-
What acts as policy enforcement point?
- What happens when two policies overlap?
Phil explained that what the Kynetx KRE engine needs is the ability to attenuate event signals. In particular, this means how to filter for:
-
Events are allowed by sender
- Events are allowed if it has certain attributes
It was agreed that we should next prepare a set of examples that illustrate how to do this, and then discuss how they can be optimized for performance.
--- USING DISCUSSION PAGES
Markus asked how tightly we should try to stick to the policy we established that discussions of proposals should be captured on the Discussion page for each proposal on the wiki.
Our conclusion was that it is fine if discussion takes place on the mailing list, and we don't have to include all details of each mailing list discussion on the Discussion page of the proposal on the wiki, but we should:
-
Summarize the key relevant points from the discussion on the Discussion page on the wiki, and
- When necessary, put links to the full detailed discussion on the mailing list.
***** DECISION POINTS FOR THIS CALL *****
This week's decision queue is the following set of proposals:
--- EQUIVALENCE LINKS AND $IS RESOLUTION (DRUMMOND & MARKUS)
We reviewed the Discussion page for the proposal.
Bill reminded everyone that a key goal is that we should be semantically precise so that XDI will support semantic reasoning. His concern is that if we add too much complexity to verbs, it won't support semantic reasoning, and we'll have to refactor, and that could be fatal.
The key to avoiding that mistake is to stay simple.
Drummond agreed with Bill and explained his view that since $is and $is! are two separate nodes in the graph, they can have distinct semantics.
Bill explained that the real point is decideability -- we need to make sure that the definitions we create result in a system where reasoning on the graph is decidable.
Drummond asked whether the potential for multiple $is statements to create a loop (a cycle in the graph) is itself a problem. Bill said no. Rather he gave an example of when one class of thiings implies something about a second class of things, and a third class of things implies something about a second class of things, and those two implications conflict.
We then discussed this point Bill made on the disucssion page:
"I think it is important that whenever we define our binary relations/predicates we explicitly say which of the following they are: symmetric, asymmetric (differs from non-symmetric), transitive, reflexive, irreflexive (differs from not necessarily reflexive), functional, inverse functional."
Drummond asked whether the same XDI predicate could have a different meaning at a logical level vs. a graph traversal level. Bill called this the difference between "implication" and "graph traversal".
Phil said it would be best to avoid this if possible.
Markus said that another consideration that helped him in thinking through the behavior of $is arcs for this proposal was the design of XDI Resolution 2.0. Drummond agreed -- its treatment of synonyms and canonical identifiers mirrors this discussion very closely.
We concluded that we all need to think on this, send thoughts to the mailing list, and revisit the proposal next week.
***** DECISION POINT QUEUE REVIEW *****
The decision queue stack is now shown on the following three auto-generated Category pages:
See also this list of proposals that need to be developed:
***** NEXT CALL *****
The next call is next week at the regular time.
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