A construction of locality-aware overlay network: mOverlay and its performance

Recently, there are many research interests in the peer-to-peer overlay architectures. Most widely used unstructured peer-to-peer (P2P) networks rely on central directory servers or massive message flooding, clearly not scalable. Distributed hash tables (DHT)-based structured overlay networks are expected to eliminate flooding and central servers, but can require many long haul messages deliveries. Thus, one important aspect of constructing an efficient overlay network is how to exploit network locality in the underlying network. In this paper, we propose a novel mechanism, mOverlay, for constructing an overlay network that takes account of locality of network hosts. The constructed overlay network can significantly decrease the communication cost between end hosts by ensuring that a message reaches its destination with small overhead and highly efficient forwarding. To construct the locality-aware overlay network, dynamic landmark technology is introduced. In this paper, we first present an effective locating algorithm for a new host joining the overlay network. Furthermore, we present theoretical analysis and simulation results to evaluate the network performance. Our analysis shows that the overhead of our locating algorithm is O(log N), where N is the number of hosts in the overlay network. Our simulation results show that the average distance between a pair of hosts in the constructed overlay network is only about 11% of the one in a traditional, randomly connected overlay network. Network design guidelines are also provided in the paper. Many large-scale network applications, such as media streaming, application-level multicasting, and media distribution can leverage our. proposed locatity-aware overlay, mOverlay, to enhance their performance.