A two-tiered reliable application layer multicast

This paper presents a two-tiered reliable application layer multicast (ALM) solution, called HRALM, to provide lossless ALM services. HRALM builds a domain-based multicast tree, and divides the members into two transport planes (i.e., Plane 1 and Plane 2) in terms of the tree. In any domain, the distance between each member and the domain header is below a given threshold, which improves the capability of topology-awareness. According to the loss detected by members in different planes, HRALM adopts different but correlated recovery solutions. In HRALM, a member duplicates and forwards the received recovery packet to each of its children if it has not received the data unit carried by the recovery packet before receiving the recovery packet, which can actively recover the loss at the downstream nodes. The simulation experiments show that HRALM has desirable transport and recovery performance.