Dominating Set Theory based Semantic Overlay Networks for Efficient and Resilient Content Distribution

Recently overlay networks have emerged as an efficient and flexible method for content distribution. An overlay network is a network running on top of another network, usually the Internet. This network is formed by a subset of underlying physical nodes. The connections between the overlay nodes are provided by overlay links, each of which is usually composed of one or more physical link. These networks are employed in many settings to provide logical communication infrastructure over an existing communication networks. The main objective of the overlay network is to reduce routing path lengths, stretched by the overlay routing process. In the existing solutions developed, a kind of fixed infrastructure in the form of excessive message exchange is necessary to guarantee good overlay properties. The scope of our effort is to construct an overlay network based on Dominating Set Theory to optimize the number of nodes for large data transfer. Fast Replica algorithm is applied to reduce the content transfer time for replicating the content within the semantic network. A dynamic parallel access scheme is introduced to download a file from different peers in parallel from the Semantic Overlay Network (SON), where the end users can access the members of the SON at the same time, fetching different portions of that file from different peers and reassembling them locally. That is, the load is dynamically shared among all the peers. To eliminate the need for retransmission requests from the end users, an enhanced digital fountain with Tornado codes is applied. Decoding algorithm at the receiver will reconstruct the original content. In this no feedback mechanisms are needed to ensure reliable delivery. This paper analyzes the performance of sequential unicast, multiple unicast and fast replica with tornado content distribution strategies in terms of content replication time and delivery ratio. This paper also analyzes the impact of dominating set theory for the construction of semantic overlay networks.