MDTCP: Practical Latency-Aware Multipath Con- gestion Control for Datacenter Networks

• Datacenter applications generate a mix of short and long flows, which have often contrasting network performance requirements. While short flows are typically sensitive to their completion time, long flows are more or less deadline agnostic but demand high throughput. Despite the availability of multiple, parallel high-capacity paths inside a datacenter network, the achievable transport-layer performance for both latency-sensitive and capacity-demanding applications is far from optimal. The reason is partly due to the inefficiency of transport protocols deployed inside datacenters. Existing transport protocols are either not capable of utilizing multiple paths offered by datacenter topologies, e.g., Datacenter TCP (DCTCP) or unsuitable for latency-sensitive applications, e.g., Multipath TCP (MPTCP), due to the employed congestion detection schemes. To address this problem, we have designed a coupled multipath congestion control algorithm called Multipath Datacenter TCP (MDTCP). MDTCP builds upon MPTCP and uses Explicit Congestion Notification (ECN) signals to detect and react to congestion before queues overflow as in DCTCP, offering both reduced latency and higher network utilization. The MDTCP congestion control has been implemented in the Linux kernel and in a packet- level network simulator. We evaluate MDTCP’s performance extensively both in a programmable datacenter network testbed andin large-scale simulations. The obtained results show that MDTCP outperforms DCTCP by reducing the average Flow Completion Time (FCT) by more than 1.6× at high load, and achieves similar performance as DCTCP at moderate network load. Moreover, it outperforms MPTCP by always achieving a lower average FCT. MDTCP also improves network utilization by 7% and 12% compared to MPTCP and DCTCP, respectively.

Ämnesord

NATURVETENSKAP  -- Data- och informationsvetenskap -- Datavetenskap (hsv//swe)

NATURAL SCIENCES  -- Computer and Information Sciences -- Computer Sciences (hsv//eng)

Nyckelord

Computer Science

Datavetenskap

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