DMTCP: Deadline-aware multipath TCP

Abstract

Multipath TCP(MPTCP) is an experimental protocol under standardization in the IETF. It enables hosts to send data over several interfaces or paths and has use cases on smartphones, datacenters or dual-stack hosts. It has proven to increase bandwidth in these cases while remaining compatible with the existing network infrastructure and applications. However, with the popularity of Online Data-Intensive applications which is under soft real-time constraints (e.g., 200ms), finishing jobs with tight deadlines is more important than bandwidth. In this paper, we propose DMTCP, an MPTCP extension that is deadline-aware and remains high throughput. DMTCP can establish subflows for deadline sensitive flows as soon as possible, and provides guaranteed transmission rates for deadline sensitive flows. It does not need to establish subflows one by one as regular MPTCP does and can establish multiple subflows simultaneously at the beginning of the three-way handshake begins. In addition, when the flow is near deadline, DMTCP will switch to utilize “the quick start” mechanism, and it will send SYN packets carrying data to further reduce flow completion time for deadline sensitive flows. Motivated by existing deadline-aware protocols, we also design a congestion control algorithm dedicated to ensuring deadline sensitive flows' completion. The algorithm can provide guaranteed transmission rates for deadline sensitive flows. When congestion happens, the deadline-aware congestion control algorithm can hold a larger congestion window for a flow with a tighter deadline. Our preliminary results show that DMTCP holds great promise in terms of deadline miss rate and goodput.