In this paper, an analytical bandwidth evaluation of generic tree-based reliable multicast protocols is presented. Our analysis is based on a realistic system model, including data packet and control packet loss, asynchronous local clocks and imperfect scope-limited local groups. Two of the four considered protocol classes use aggregated acknowledgments (AAKs). With AAKs they are able to provide reliability even in case of node failures. All tree-based protocols provide good scalability for large receiver groups. Relating to protocols with aggregated acknowledgments, the analysis shows only little additional bandwidth overhead and therefore high throughput rates. Finally, we have analyzed the influence of the branching factor on a protocol's performance. Our results show that the optimal branching factor depends mainly on the probability for receiving messages from other local groups. If local groups are assigned to a separate multicast address, the optimal branching factor is 2. On the other hand, if TTL scoping is used as in RMTP or TMTP and therefore the probability for receiving messages from other local groups is greater than zero, larger local groups provide better performance.