Update Transport Mechanism Based On Dependency. P2p Network Realization

Collaboration Software is that all person of different role to corporate together in a circumstance and to achieve a common project. Its characteristic is take team-work and project management as its objective, integrate separated resource together to structure a share information system. Implement cooperation through network in order to provide data transmission, data share, data edit and data consult. The precondition of collaboration application is to build a platform of information intercourse which is a logical information delivery platform based on communication, ensure the information be delivered no-faulty, instant and consistent.How to implement the consistency of data update is the core problem of collaboration application. It includes two aspects to achieve update consistency: one is the organization strategy of different data copies among peers and the update propagation, another one is how to deliver the update message according to data consistency when they accepted by the receiving peer.In order to solve the problem , we introduce a update propagation mechanism based on casually relations and we carry out three-step acknowledgement model. Our work include1)Define the semantics of data consistency. Different collaboration application ask for different consistency, we classify the consistency into three standards: local order, casual order, total order. We divide the relation of update message into three kinds: commutative relation, conflicting relation, caused-by relation. Explain the contraction between data consistency and relation of update message.2) Analyze the key technology of how to implement update mechanism, explain the solution of update interaction in collaboration application from three angles which are update initiation, update transmission and update receiving. Analyse the Extraction of Logical Concurrency operation in update initiation stage and the epidemic model of update propagation in details.3) Introduce a update propagation mechanism based on casually relation, according to the analysis of interaction in collaboration application, we implement three-step acknowledgement model and demonstrate its a model based on casually relation. We achieve the prototype of three-step acknowledgement model under peer-to-peer network and point out the improvement methods under WAN.