SSM extensions: network layer support for multiple senders in SSM

Source specific multicast (SSM) provides native support for single sender multicast applications. Current proposals for supporting multiple sender applications on top of SSM includes using multiple SSM channels or using an application layer relay mechanism on top of SSM. These approaches have potential scalability or single point of failure problems, respectively. In this paper, we propose network layer extensions to SSM. Our extensions provide a convenient mechanism for SSM group owners to include additional senders in their multicast applications. We present our SSM extensions model and provide a detailed discussion on the protocol operation under various scenarios. We also examine the protocol performance by comparing it to alternative approaches on several performance metrics. With SSM Extensions, we introduce a small number of changes into the existing infrastructure and in return, provide an effective and efficient mechanism to support multiple-sender applications on top of SSM.