1. 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

2. Time is Money

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

4. 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

5. ATP: A Protocol with Error Correction1 2
1,2 3 4 5
3,4,5 6 7 8 9
6,7,8,9 10 11 12

6. Results
Evaluation

7. Testbed

8. TCP - Background Traffic

9. Tail Latency

10. 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

11. 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

12. Implementation Sender Receiver 1 2 3 1,2,3 1 2 3