Vincent Roca

A survey of proposals for an alternative group communication service

As expectations for the Internet to support multimedia applications grow, new services need to be deployed. One of them is the group communication service for one-to-many or many-to-many data delivery. After more than a decade of important research and development efforts, the deployment of multicast routing in the Internet is far behind expectations. Therefore, a first motivation for an alternative group communication service is to bypass the lack of native IP multicast routing. Although less efficient and scalable than native multicast routing, such alternative services are generally suitable for the purpose. A second possible motivation is to go beyond the limitations of classic multicast routing for very specific working environments. We identify, classify, and discuss some of these alternative approaches.

Impact of simple cheating in application-level multicast

We study the impact of cheating nodes in application-level multicast overlay trees. We focus on selfish nodes acting independently, cheating about their distance measurements during the control phase building or maintaining the tree. More precisely, we study, through simulations, the impact of simple cheating strategies in four protocols, representatives of different application-level multicast protocol families: HBM (a protocol based on a centralized approach), TBCP (a distributed, tree first protocol), NICE (a distributed, tree first protocol based on clustering) and NARADA (a mesh first protocol). We evaluate the impact of cheats on the performance of the overlay trees as perceived by their nodes and the underlying network.