P2P middleware

Replication

Consistency

Asynchronous

Disconnected work

Telex Advantages

Replication is an essential feature of a distributed system, but updates cause the issue of consistency between replicas. Strong consistency is easy to understand but impossible in peer2peer environment; weaker models are complex. Our Actions-Constraints Framework (ACF) provides a formal model for modelling, comparing, and reasoning about consistency.Developers of distributed collaborative applications in Peer2Peet environment need decentralized P2P replication middleware and consistency protocols.Telex is a Peer2Peer semantic-oriented middleware based on Actions-Constraints Framework. However, it is not intuitive for collaborative-application developers to express application semantics using the ACF. In fact, the application design is ad-hoc and hard to validate.I aim to facilitate Peer2Peer collaborative application design. For that purpose, I propose a generic methodology for more principle designing, an extension of the ACF to facilitate expressing the application semantics, and a use of automatic prover to validate the application design.

Shared Calendar Application

Calendar

CalendarCalendar

Share Calendars Conflict

NonCommuting

Telex Middelware

Actions-Constraints Framework (ACF)Action

Constraint

Methodology:

Any information

Implicit/Explicit

Shared

Consistency

Explicit Telex Object

Ad-hoc design

Non intuitive

Describe application semantics:

Static Constraints

Hard to validate

ACF Extension

Hybridizing ACF and State-Based replication:

Correlate constraints with a state.

Dynamic constraints

Design Tools

Automatic Prover

Actions

Constraints

Invariants

Validation / Count examples

Challenges

Future Challenges

Future Challenges

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Lamia BENMOUFFOK _ Marc SHAPIRO Lip6/INRIA REGAL Team _ Paris 6 University Lamia.Benmouffok@lip6.fr