Abstract—Distributed interactive applications have become increasingly popular, making it important to address their communication needs, where one of the needs is group communication. In this paper, we consider the applications in which it is at any given time possible to divide its users into groups. The group membership changes over time, and the group division is unrelated to the physical proximity. As a way of enabling the group communication in distributed interactive applications, we choose application layer multicast. We use simulation to evaluate several dynamic algorithms for managing overlay multicast trees. They are compared with respect to four metrics that can be relevant for a distributed interactive application. These are total tree cost, diameter, reconfiguration time and stability. We demonstrate algorithms that perform well for these metrics although they do not consider all users during reconfiguration. I.

Abstract — Communication in highly interactive distributed applications, such as massive multiplayer online games, can often be performed efficiently using multicast, i.e., application level multicast. However, in applications with a very dynamic group management, the multicast tree will have frequent changes, and in applications that have stringent latency requirement, this operation needs to be fast. Current multicast approaches either have no notion of reconfiguration, they do not care about tree reconstruction latency or wrongly assume that this is a fast, atomic operation. In this paper, we have focused on dynamic reconfiguration and have tested different ways for a node to join a tree. Our results show that this is an important issue for the class of highly interactive distributed applications. I.

In past years, researchers have proposed the Core Based Tree (CBT) and Protocol Independent Multicast (PIM) protocols to route multicast data on the Internet. Such protocols need to locate the Core of a group to achieve efficient multicast routing. In this paper, we propose a scalable distributed protocol that can be used to move the Core to near-optimal location in the dynamic multicast tree, and that allows the Core to migrate efficiently when the multicast tree is expanded or shrunk. Our protocol does not require knowledge of the complete network topology, and information of all the members is distributed among local Agents; the Core only maintains the information of Agents of the group. Also, only the Agents participate in Core selection. Therefore, the proposed protocol reduces the runtime overhead and message complexity while performing Core migration.

Abstract — Communication in highly interactive distributed applications, such as massive multiplayer online games, can often be performed efficiently using multicast, i.e., application level multicast. However, in applications with a very dynamic group management, the multicast tree will have frequent changes, and in applications that have stringent latency requirement, this operation needs to be fast. Current multicast approaches either have no notion of reconfiguration, they do not care about tree reconstruction latency or wrongly assume that this is a fast, atomic operation. In this paper, we have focused on dynamic reconfiguration and have tested different ways for a node to join a tree. Our results show that this is an important issue for the class of highly interactive distributed applications. I.

Abstract—Distributed interactive applications have become increasingly popular, making it important to address their communication needs, where one of the needs is group communication. In this paper, we consider the applications in which it is at any given time possible to divide its users into groups. The group membership changes over time, and the group division is unrelated to the physical proximity. As a way of enabling the group communication in distributed interactive applications, we choose application layer multicast. We use simulation to evaluate several dynamic algorithms for managing overlay multicast trees. They are compared with respect to four metrics that can be relevant for a distributed interactive application. These are total tree cost, diameter, reconfiguration time and stability. We demonstrate algorithms that perform well for these metrics although they do not consider all users during reconfiguration. Fig. 1. Location in the real world, and area of interest in the virtual world. I.