SAM Overlay Protocol
The previously proposed Hybrid Overlay Multicast Framework uses a structured peer-to-peer overlay to connect peers in different types of multicast regions of the Internet. We use AMT (Automatic IP Multicast Without Explicit Tunnels) to connect peers in ALM (Application Layer Multicast) regions with peers in native multicast regions. Here we define the overlay messaging needed to support the multicast tree operations. One goal of this approach is to ensure that the SAM framework is compatible with the P2P-SIP overlay, which is still being defined. Another goal is to be overlay agnostic so that different overlay algorithms can interoperate in a single SAM (Scalable Adaptive Multicast) session.