ETM - An Optimized Routing Protocol for Mobile SSM Sources

Mobility is considered a key technology of the next generation Internet and has been standardized within the IETF. Rapidly emerging multimedia group applications such as IPTV, MMORPGs and video conferencing increase the demand for mobile group communication, but a standard design of mobile multicast is still awaited. The traditional Internet approach of Any Source Multicast (ASM) routing remains hesitant to spread beyond walled gardens, while the simpler and more selective Source Specific Multicast (SSM) is expected to globally disseminate to many users and services. However, mobility support for Source Specific Multicast is still known to be a major open problem. In this paper we introduce the Enhanced Tree Morphing (ETM), an optimized multicast routing protocol for transforming (morphing) source specific distribution trees into optimal trees rooted at a relocated source. Following up on previous results for the initial Tree Morphing, we present enhancements that lead to a simpler protocol with significantly optimized performance values in both, forwarding performance and protocol robustness. Extensive evaluations based on real-world topology data are part of this work.