Design and Implementation of Software-Based Dynamically Connected Transport

Abstract

Most RDMA applications are based on either RC QP(Reliable Connected Queue Pair) or UD QP(Unreliable Datagram Queue Pair). RC QP has advantages on usability but disadvantages on scalability while UD QP is scalable but hard to use. Dynamically Connected (DC) transport has been introduced to address the limitations when using one of the existing QPs. However, DC transport is only available with hardware support. In this paper, we design and implement a totally software-based DCT prototype to eliminate hardware dependency. Our experimental results show that although our prototype adds a first-time connection overhead it could provide the advantages of both RC QP and UD QP. We also write and evaluate a DC QP-based application to prove its effectiveness compared to RC QP-based one.