Multicast network services advantageously complement multimedia information and communication technologies, as they open up the realm for highly scalable multicustomer applications. Mobile environments providing shared limited bandwidth to a growing number of users will emphasize the need for multicast support even further. The traditional Internet approach of Any Source Multicast (ASM) routing, though, remains hesitant to spread beyond limited, controlled environments. It is widely believed that simpler and more selective mechanisms for group distribution in Source Specific Multicast (SSM) will globally disseminate to many users of multicast infrastructure and services. However, mobility support for Source Specific Multicast is still known to be a major open problem.

This paper presents a light-weight, secure implementation of the Tree Morphing protocol on the IPv6 network layer. This distributed routing algorithm allows for a continuous adaptation of multicast shortest path trees to source mobility. The approach introduced here is built upon standardized mobility signaling and includes strong authentication by means of cryptographically generated addresses. It neither requires definition of new protocol elements nor significant changes to the forwarding plane.