OCTOPUS: A Hybrid Scheduling Strategy for P2P VoD Services

Peer-to-Peer (P2P) networks have been shown to be a promising approach to provide large-scale Video on Demand (VoD) services over Internet for its potential high scalability. However, for a normal peer, how to efficiently schedule media data to multiple asynchronous peers for VoD services in such networks remains a major challenge. Hereby we propose a hybrid scheduling scheme for data dissemination in P2P VoD system in this paper, called OCTOPUS, which is combined with adaptive scheduling scheme at normal time and special scheduling strategy emergently. Usually each peer is given a value, meaning scheduling bandwidth to represent service capacity, which is an integrated evaluation for peer´s bandwidth and services ability, also including statistical characteristics about historical data transferring. According to the value, one peer can adjust the expectation of each neighbor´s abilities and send scheduling request of media data to all partners. In case of failure scheduling, emergent scheduling scheme will be called and limited data requests will be sent to media servers. OCTOPUS scheme helps to make sufficient utilization of end-peers´ resource, alleviate the load of source server and improve their scalability. Experimental result from a P2P VoD system, GridCast, based on OCTOPUS schemes, shows that OCTOPUS achieves obvious effect.