Graduate School and Research Center In communication systems

Seminar: Managing the topology of unstructured overlay networks.

Joao Leitao - INESC-ID, Portugal

Digital Security

Date: October 2, 2012

The peer-to-peer (P2P) paradigm has emerged more than 10 years ago as a viable alternative to overcome limitations of the client-server model namely, in terms of scalability, fault-tolerance, and even operational costs. This paradigm has gained significant popularity with its successful application in the context of file sharing applications. The success of these applications is illustrated by systems such as Napster, Emule, Gnutella, and recently, BitTorrent. In order to ensure the scalability of these solutions many P2P services operate on top of unstructured overlay networks, which are logical networks deployed at the application level. Unstructured overlay networks establish random neighboring associations among participants of the system. Although the random nature of these overlays is desirable by many P2P services, the resulting topology may present sub-optimal characteristics, for instance from the point of view of link latency. This may have a significant impact of the performance of P2P services executed over these overlays. This talk will discuss several techniques that can be employed to manage the topology of unstructured overlay networks, allowing to imbue some form of relaxed topology over them in a decentralized fashion. By manipulating the topology of these overlay one can improve the operation of several P2P services and applications, which is illustrated through particular case-study examples.

Managing the topology of unstructured overlay networks.