Towards MPI progression layer elimination with TCP and SCTP

MPI middleware glues together the components necessary for execution. Almost all implementations have a communication component also called a message progression layer that progresses outstanding messages and maintains their state. The goal of this work is to thin or eliminate this communication component by pushing the functionality down onto the standard IP stack in order to take advantage of potential advances in commodity networking. We introduce a TCP-based design that successfully eliminates the communication component. We discuss how this eliminated TCP-based design doesn't scale and show a more scalable design based on the stream control transmission protocol (SCTP) that has a thinned communication component. We compare the designs showing why SCTP one-to-many sockets in their current form can only thin the communication component. We show what additional features would be required of SCTP to enable a practical design with a fully eliminated communication component