Poster: The Congestion Path Multiplicity Problem in RDMA Multicast Congestion Control

In multicast RDMA, the sender overestimates congestion signals when multiple paths are congested. This congestion path multiplicity problem is hard to be resolved because RDMA sender cannot identify the sender of congestion signals due to RDMA protocol regulation. In this paper, we propose a new approach that the branching switch filters congestion signals from the worst congested interface. Our evaluation results show that our proposed method can adequately resolve the congestion path multiplicity problem.