In this paper, to investigate the processing requirements at each node and offered network load of receiver-based and router-based protocols, we analyze the number of packet transmissions on each link until all receivers receive a packet for an arbitrary multicast-tree topology and packet loss probability considering the correlation between loss events of a packet for different receivers. In order to show the effectiveness of the analytical results, we demonstrate the numerical examples for various conditions. The numerical results show that local recovery protocols, especially router-based protocol can reduce the offered network load due to data packets and their acknowledgements, and can decentralize processing requirement of sending nodes effectively. Further, we reveal the influence of the locations of group senders on the performance of both protocols.

In reliable multicast communications, retransmission control plays an important role from the viewpoint of scalability. Previous works show that the implosion of control packets, e.g. ACKs or NAKs, degrades the total performance of reliable multicast communications. Local recovery which enables receivers receiving a packet successfully to initiate recovering a lost packet may have the possibility to solve this scalability problem. This paper presents the performance evaluation of local recovery caused by grouping receiving nodes in reliable multicast communication. There seems to be many features dominating the performance of local recovery, the number of nodes in a group, the shared loss occurring simultaneously at multiple receivers and so on. When the number of receivers in a group increases, the geographical expansion of a group will degrade the delay performance of the receivers. In a configuration where most nodes in a local-recovery group suffer from shared loss, the failure of local recovery degrades the total performance. Our simulation results under a hierarchical network topology like the real Internet show that a local-recovery group configuration with two-adjacent MANs grouping performs well.