Date Added: Sep 2009
In decentralized networks such as Peer-to-Peer (P2P), challenged networks (e.g. DTNs) or Wireless Mesh networks (WMN) nodes have to rely on the service provided by other participating nodes. From a node's perspective it could be desirable to utilize the other nodes' services without contributing its own resources in return. Examples of such behavior are non-forwarding of messages in WMNs/DTNs and refusal to upload in P2P networks. This constant consumption of network resources without reciprocity is often referred to as free-riding. Free-riders significantly decrease the overall performance of the network. Consequently, ways to identify and punish them are subject to extensive research.