MANET multicast with multiple gateways

A current challenge in interconnecting mobile ad hoc networks (MANETs) with backbone legacy networks is the lack of compatibility between different multicast routing protocols when using multiple gateways, due to differences in both forwarding semantics and implementations of the different protocols. We present designs and experimental results involving the interconnection of the simplified multicast forwarding (SMF) MANET protocol with the protocol independent multicast (PIM) protocols, both dense- and sparse-mode. We illustrate the types of interconnections and multicast forwarding configurations, evaluate performance issues of existing approaches, and propose solutions to them. We describe techniques for allowing multiple gateways to dynamically detect one another and coordinate the forwarding behavior. We also highlight how the open source implementations of these protocols can be combined. We show that SMF can be connected to both PIM-SM and PIMDM variants, and that policies at the gateways can control the fine-grained forwarding behavior on a per-group basis.