In this paper, we address the problem of content placement in peer-to-peer systems, with the objective of maximizing the utilization of peers' uplink bandwidth resources. We consider system performance under a many-user asymptotic. We distinguish two scenarios, namely "Distributed Server Networks" (DSN) for which requests are exogenous to the system, and "Pure P2P Networks" (PP2PN) for which requests emanate from the peers themselves. For both scenarios, we consider a loss network model of performance, and determine asymptotically optimal content placement strategies in the case of a limited content catalogue. We then turn to an alternative "large catalogue" scaling where the catalogue size scales with the peer population. Under this scaling, we establish that storage space per peer must necessarily grow unboundedly if bandwidth utilization is to be maximized. Relating the system performance to properties of a specific random graph model, we then identify a content placement strategy and a request acceptance policy which jointly maximize bandwidth utilization, provided storage space per peer grows unboundedly, although arbitrarily slowly, with system size. • Distributed Server Network (DSN): Requests to download contents come only from pure users, and can be regarded as external requests. • Pure P2P Network (PP2PN): There are no pure users in the system, and boxes do generate content requests, which can be regarded as "internal".
In REF , Tan and Massoulié designed the caching strategies in P2P system based on the two scenarios: (1) pure P2P network and (2) distributed server networks.
Optimal content placement for peer-to-peer video-on-demand systems
2011 Proceedings IEEE INFOCOM
2011 Proceedings IEEE INFOCOM
Computer Science Mathematics