Cooperative Caching for Multimedia Streaming in Overlay Networks

Traditional data caching, such as web caching, only focuses on how to boost the hit rate of requested objects in caches, and therefore, how to reduce the initial delay for object retrieval. However, for multimedia objects, not only reducing the delay of object retrieval, but also provisioning reasonably stable network bandwidth to clients, while the fetching of the cached objects goes on, is important as well. In this paper, we propose our cooperative caching scheme for a multimedia delivery scenario, supporting a large number of peers over peer-to-peer overlay networks. In order to facilitate multimedia streaming and downloading service from servers, our caching scheme (1) determines the appropriate availability of cached stream segments in a cache community, (2) determines the appropriate peer for cache replacement, and (3) performs bandwidth-aware and availability-aware cache replacement. By doing so, it achieves (1) small delay of stream retrieval, (2) stable bandwidth provisioning during retrieval session, and (3) load balancing of clients' requests among peers

On the Topology Maintenance of Dynamic P2P Overlays through Self-Healing Local Interactions

This paper deals with the use of self-organizing protocols to improve the reliability of dynamic Peer-to-Peer (P2P) overlay networks. We present two approaches, that employ local knowledge of the 2nd neighborhood of nodes. The first scheme is a simple protocol requiring interactions among nodes and their direct neighbors. The second scheme extends this approach by resorting to the Edge Clustering Coefficient (ECC), a local measure that allows to identify those edges that connect different clusters in an overlay. A simulation assessment is presented, which evaluates these protocols over uniform networks, clustered networks and scale-free networks. Different failure modes are considered. Results demonstrate the viability of the proposal.Comment: A revised version of the paper appears in Proc. of the IFIP Networking 2014 Conference, IEEE, Trondheim, (Norway), June 201

Self-Healing Protocols for Connectivity Maintenance in Unstructured Overlays

In this paper, we discuss on the use of self-organizing protocols to improve the reliability of dynamic Peer-to-Peer (P2P) overlay networks. Two similar approaches are studied, which are based on local knowledge of the nodes' 2nd neighborhood. The first scheme is a simple protocol requiring interactions among nodes and their direct neighbors. The second scheme adds a check on the Edge Clustering Coefficient (ECC), a local measure that allows determining edges connecting different clusters in the network. The performed simulation assessment evaluates these protocols over uniform networks, clustered networks and scale-free networks. Different failure modes are considered. Results demonstrate the effectiveness of the proposal.Comment: The paper has been accepted to the journal Peer-to-Peer Networking and Applications. The final publication is available at Springer via http://dx.doi.org/10.1007/s12083-015-0384-

A Framework for Mobile Applications based on a structured P2P Overlay

P2P applications are increasingly popular. Unlike traditional client-server applications they do not require central server resources. This makes them less costly to host and maintain. While there have been a large number of P2P applications been developed for PC based systems, there are only very few for mobile appliances, such as mobile phones or networked PDAs, and even fewer which operate successfully on the public mobile data network (GPRS, 3G), rather than WiFi. This is largely due to the difficulties posed by the restrictive data access to mobile devices (NATs, Firewalls by the network operators) and traditionally high charges for data communications. Recently, the latter point has been virtually removed by the introduction of flat-rate data packages by the operators. This paper (and demo) present a framework and applications based on a structured P2P overlay network which can successfully operate on the public data network

Message Passing in Semantic Peer-to-Peer Overlay Networks

Peer-to-Peer (P2P) systems rely on machine-to-machine ad-hoc communications to offer services to a community. Contrary to the classical client-server architecture, P2P systems consider all peers, i.e., all nodes participating in the network, as being equal. Hence, peers can at the same time act as clients consuming resources from the system, and as servers providing resources to the community. P2P applications function on top of existing routing infrastructures, typically on top of the IP network, and organize peers into logical and decentralized structures called overlay networks. In this column, we discuss exploratory research related to data management in P2P overlay networks. First, we discuss the notions of unstructured and structured P2P overlay networks. Then, we discuss data management in such networks by introducing an additional layer to handle semantic heterogeneity and data integration. Finally, we present a method based on sum-product message passing to detect inconsistent information in this setting