Review of "Less is More: Trading a little Bandwidth for Ultra-Low Latency in the Data Center"

18 Nov 2015

Review of "Less is More: Trading a little Bandwidth for Ultra-Low Latency in the Data Center"

Problem: Traditionally network goodness and fairness are expressed in terms of bandwidth. Latency is rarely a primary concern because delivering the highest level of bandwidth essentially entails driving up latency – at the mean and especially at the tail. However, as the real-time requirement of applications becomes more and more critical, latency of networking stack also need to be taken care of.

Key points and trade-offs: This paper proposes HULL witch sacrifices a little bit of bandwidth and get drastically lower average and tail average latencies in data centers. The way it does this is it leaves a "bandwidth headroom" by using Phantom Queues that delivers signals before network links are fully utilized and queues form at switches. It also employs DCTCP to adaptively respond to congestions and to mitigate the bandwidth penalties arise from operating in a buffer-less fashion. Packet pacing is used to counter burstiness caused by Interrupt Coalescing and Large Send Offloading.

Will this paper be influential in 10 years? Maybe. Generally, it's a good improvement of the existing protocol which didn't pay too much attention on the network latency.

Hu2la - Automated UI design