9406007 Estrin The proposal begins with a brief review of the evolution of multicast routing and identification of the scaling issues raised by the introduction of multicast services in a global-scale internet. We then present criteria for evaluating different solutions to the scaling issues. Given these evaluation criteria we outline our proposed solution, called PIM. PIM could significantly improve the scaling properties of multicast routing and is capable of providing better service quality than alternative scalable multicast schemes such as Core Based Trees. We present preliminary simulation results comparing the performance of different distribution trees. However, fully characterizing the performance of multicast routing schemes in very large, heterogeneous, internetworks is not trivial; and ``learning through experience'' in operational networks that are of the size of our target environment (i.e., the global internet), is not feasible . Characterizing multicast protocols is not only challenging because of the scale of the target internet, but also because of the complexity and flexibility built into the protocols themselves. Moreover, a single multicast protocol such as PIM, may be used (or configured) in a variety of ways that directly impact performance. Therefore, to characterize our proposed multicast approach, and to evaluate it relative to alternatives, we propose extensive simulation studies. The proposed research is composed of three parts: 1) an extensive simulation study to characterize the scaling properties and tradeoffs presented by the proposed mechanisms, 2) an investigation of alternative aggregation mechanisms to further extend scalability (using our constructed simulation tools for their evaluation), and, 3) a prototype implementation of the proposed scheme for testing in laboratory and testbed networks. ***
