ATP TCP Reducing the Latency-Tail of Short-Lived Flows: Adding Forward Error Correction in Data Centers Klaus-Tycho Foerster, Demian Jaeger, David Stolz, and Roger Wattenhofer ETH Zurich

Time is Money

Datacenter Traffic Time in Datacenter S. Kandula et al., The Nature of Datacenter Traffic. IMC 2009 Time in Datacenter

Overview Problem TCP is sensitive to retransmissions Prior Work Induces latency-tail in congested networks → Goal Prior Work Add forward error correction (FEC) at link layer Wireless networks Add general overhead Reserve capacity Our Approach Adaptive FEC on packet level 1 2 1,2,3 3

ATP: A Protocol with Error Correction 1 2 1,2 3 4 5 3,4,5 6 7 8 9 6,7,8,9 10 11 12

Results Evaluation

Testbed

TCP - Background Traffic

Tail Latency

Conclusion ATP Transport Layer Protocol for data centers Improve latency of small flows by using variable FEC Evaluation Fairness to TCP and other ATP streams Similar to TCP in not congested network 20 Times smaller Tail latency compared to TCP in busy network 1 2 1,2,3 3

ATP TCP Reducing the Latency-Tail of Short-Lived Flows: Adding Forward Error Correction in Data Centers Klaus-Tycho Foerster, Demian Jaeger, David Stolz, and Roger Wattenhofer ETH Zurich

Implementation Sender Receiver 1 2 3 1,2,3 1 2 3 20.11.201820.11.201820.11.2018