Optimal Content Retrieval Latency for Chunk Based Cooperative Content Replication in Delay Tolerant Networks

Abstract

Modern content distribution networks face an increasing multitude of content generators. In order to reach the minimal content retrieval latency in the content distribution networks, content shall be disseminated towards consumers based on its popularity taken from the content distribution networks. This, Combined with dividing media into chunks (heterogeneous valuation of information) and contact duration of the consumers with the access points in delay tolerant networks led us to a novel system for content management in large scale distributed systems. In order to determine where to replicate content we formulated the problem as an integer programming problem. The cost function of this minimization problem is the accumulated weighted communication delay among the content replication servers and also the main content server. Various practical constraints such as limited total budget for content replication in each service provider, limited storage size and downlink bandwidth of the content replication servers are considered. A centralized solution to the problem is derived which gives the performance bound for any decentralized content replication strategy for the presented scenarios