Single connection emulation (SCE): an architecture for providing a reliable multicast transport service

We present a novel architecture for providing a reliable multicast transport service over existing protocol stacks. These protocol stacks ordinarily support reliable unicast transport layer connections over a network layer which is capable of providing an unreliable multicasting service. We propose the addition of a new single connection emulation (SCE) sublayer between the unicast transport layer and the multicast network layer. This added layer mimics the single destination network layer interface to the transport layer and interfaces with the multicast network layer to provide the necessary multicast functionality. The new architecture also enables interactions between applications and the SCE, thus allowing the applications to control the semantics of the reliable multicast connection. We discuss the design issues that need to be considered when such a sublayer is to be introduced. We also discuss an implementation of this new approach using the TCP/IP protocol stack and present some preliminary experimental results