Study of the Topology Mismatch Problem in Peer-to-Peer Networks

The advantages of peer-to-peer (P2P) technology are innumerable when compared to other systems like Distributed Messaging System, Client-Server model, Cloud based systems. The vital advantages are not limited to high scalability and low cost. On the other hand the p2p system suffers from a bottle-neck problem caused by topology mismatch. Topology mismatch occurs in an unstructured peer-to-peer (P2P) network when the peers participating in the communication choose their neighbors in random fashion, such that the resultant P2P network mismatches its underlying physical network, resulting in a lengthy communication between the peers and redundant network traffics generated in the underlying network[1] However, most P2P system performance suffers from the mismatch between the overlays topology and the underlying physical network topology, causing a large volume of redundant traffic in the Internet slowing the performance. This paper surveys the P2P topology mismatch problems and the solutions adapted for different applications

Testing Peers' Volatility

International audiencePeer-to-peer (P2P) is becoming a key technology for software development, but still lacks integrated solutions to build trust in the final software, in terms of correctness and security. Testing such systems is difficult because of the high numbers of nodes which can be volatile. In this paper, we present a framework for testing volatility of P2P systems. The framework is based on the individual control of peers, allowing test cases to precisely control the volatility of peers during execution. We validated our framework through implementation and experimentation on two open-source P2P systems. Through experimentation, we analyze the behavior of both systems on different conditions of volatility and show how the framework is able to detect implementation problems

A New Authentication Model Based on CL-PKC in Resource limited P2P Systems

This paper proposes a new authentication model based on CL-PKC technology (Certificate less public key cryptography) in peer-to-peer systems. With the progress in peer-to-peer technology, lots of things related to the security problems of peer-to-peer systems have been exposing. To solve these security problems, authentication must be settled firstly. So this paper develops an authentication method based on CL-PKC technology, considering the dynamic properties of hybrid peer-to-peer systems. This method simplifies the procedure of getting public keys and authentication procedure, so the efficiency is increased, and the mount of bandwidth required is lower. This method is very fit to the systems with limited resources

Localized Multistreams for P2P Streaming

Streaming video over the Internet, including cellular networks, has now become a commonplace. Network operators typically use multicasting or variants of multiple unicasting to deliver streams to the user terminal in a controlled fashion. P2P streaming is an emerging alternative, which is theoretically more scalable but suffers from other issues arising from the dynamic nature of the system. Users' terminals become streaming nodes but they are not constantly connected. Another issue is that they are based on logical overlays, which are not optimized for the physical underlay infrastructure. An important proposition is to find effective ways to increase the resilience of the overlay whilst at the same time not conflicting with the network. In this article we look at the combination of two techniques, redundant streaming and locality awareness, in the context of both live and video-on-demand streaming. We introduce a new technique and assess it via a comparative, simulation-based study. We find that redundancy affects network utilization only marginally if traffic is kept at the edges via localization techniques

Characterization of P2P Systems

Understanding existing systems and devising new P2P techniques relies on having access to representative models derived from empirical observations of existing systems. However, the large and dynamic nature of P2P systems makes capturing accurate measurements challenging. Because there is no central repository, data must b

Random graphs as models of hierarchical peer-to-peer networks

Abstract This paper proposes the development and application of random graphs-based performance evaluation techniques to understand design trade-offs for hierarchical unstructured peer-to-peer networks. In particular, the connections between lower and higher level peers (that are known as leaves and ultra-peers in the Gnutella jargon) are modeled as a bipartite random graph while the overlay network used by ultra-peers to forward queries is modeled as a generalized random graph. Both the random graph models consider peers of either level as partitioned into classes; this feature is included in the model description to consider the mismatch between the logical topology of the application and the physical deployment of peers throughout the Internet. To assign realistic values to the input model parameters and to validate the model predictions we obtained snapshots of the Gnutella application topology at both levels and conducted simulation experiments on these snapshots. The paper highlights a few exploitations of the modeling technique with a particular focus on the evaluation of the impact of locality awareness on user and network performance measures