2 P2P or Not 2 P2P?

In the hope of stimulating discussion, we present a heuristic decision tree that designers can use to judge the likely suitability of a P2P architecture for their applications. It is based on the characteristics of a wide range of P2P systems from the literature, both proposed and deployed.Comment: 6 pages, 1 figur

A Candour-based Trust and Reputation Management System for Mobile Ad Hoc Networks

The decentralized administrative controlled-nature of mobile ad hoc networks (MANETs) presents security vulnerabilities which can lead to attacks such as malicious modification of packets. To enhance security in MANETs, Trust and Reputation Management systems (TRM) have been developed to serve as measures in mitigating threats arising from unusual behaviours of nodes. In this paper we propose a candour-based trust and reputation system which measures and models reputation and trust propagation in MANETs. In the proposed model Dirichlet Probability Distribution is employed in modelling the individual reputation of nodes and the trust of each node is computed based on the node’s actual network performance and the quality of the recommendations it gives about other nodes. Cooperative nodes in our model will be rewarded for expanding their energy in forwarding packets for other nodes or for disseminating genuine recommenda-tions. Uncooperative nodes are isolated and denied the available network resources. We employed the Ruffle algorithm which will ensure that cooperative nodes are allowed to activate sleep mode when their service is not required in forwarding packets for its neighbouring trustworthy nodes. The proposed TRM system enshrines fairness in its mode of operation as well as creating an enabling environment free from bias. It will also ensure a connected and capacity preserving network of trustworthy node

Observation-based Cooperation Enforcement in Ad Hoc Networks

Ad hoc networks rely on the cooperation of the nodes participating in the network to forward packets for each other. A node may decide not to cooperate to save its resources while still using the network to relay its traffic. If too many nodes exhibit this behavior, network performance degrades and cooperating nodes may find themselves unfairly loaded. Most previous efforts to counter this behavior have relied on further cooperation between nodes to exchange reputation information about other nodes. If a node observes another node not participating correctly, it reports this observation to other nodes who then take action to avoid being affected and potentially punish the bad node by refusing to forward its traffic. Unfortunately, such second-hand reputation information is subject to false accusations and requires maintaining trust relationships with other nodes. The objective of OCEAN is to avoid this trust-management machinery and see how far we can get simply by using direct first-hand observations of other nodes' behavior. We find that, in many scenarios, OCEAN can do as well as, or even better than, schemes requiring second-hand reputation exchanges. This encouraging result could possibly help obviate solutions requiring trust-management for some contexts.Comment: 10 pages, 7 figure

Incentives in peer-to-peer and grid networking

Today, most peer-to-peer networks are based on the assumptionthat the participating nodes are cooperative. Thisworks if the nodes are indifferent or ignorant about the resourcesthey offer, but limits the usability of peer-to-peernetworks to very few scenarios. It specifically excludes theirusage in any non-cooperative peer-to-peer environment, beit Grid networks or mobile ad-hoc networks. By introducingsoft incentives to offer resources to other nodes, we seean overall performance gain in traditional file-sharing networks.We also see soft incentives promoting the convergenceof peer-to-peer and Grid networks, as they increasethe predictability of the participating nodes, and thereforethe reliability of the services provided by the system as awhole. Reliability is what is required by Grid networks, butmissing in peer-to-peer networks