Evaluation of TCP BBR in Comparison with Other Congestion Avoidance - - PowerPoint PPT Presentation

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Evaluation of TCP BBR in Comparison with Other Congestion Avoidance Algorithms

Benedikt Jaeger

September 13, 2017 Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Contents

TCP BBR Related Work Parameters & Measurements Next Steps

• B. Jaeger

– TCP BBR 2

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Bottleneck-Bandwidth & RTT

Congestion-based Congestion Control

• 1. estimate bandwidth (max-filter)
• 2. measure propagation delay (min-filter)
• 3. compute BDP
• B. Jaeger

– TCP BBR 3

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Bottleneck-Bandwidth & RTT

Congestion-based Congestion Control

• 1. estimate bandwidth (max-filter)
• 2. measure propagation delay (min-filter)
• 3. compute BDP

Goals:

• keep in-flight data = BDP
• send with bottleneck-bandwidth
• B. Jaeger

– TCP BBR 3

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Bottleneck-Bandwidth & RTT

bottleneck

Time Sending Rate

• B. Jaeger

– TCP BBR 4

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Bottleneck-Bandwidth & RTT

bottleneck

Time Sending Rate BBR Reno

• B. Jaeger

– TCP BBR 5

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Bottleneck-Bandwidth & RTT

Wireshark IO Graphs: s1

2 4 6 8 10 12 Time (s) 30000 60000 90000 120000 150000 180000 Bandwidth RTT 10 ms Intervals

Single BBR flow with

• 10 Mbit/s bottleneck-bandwidth
• 40 ms RTT
• B. Jaeger

– TCP BBR 6

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Related Work

Source

• ther

CCAs mixed CCAs different RTTs Number

• f Hosts

BBR,2016

• x

x

• Ma,6.2017

x x

• Hock,8.2017
• ()
• Reproduced Results:

BBR,2016: network changes, fairness to itself Ma,6.2017: RTT unfairness Hock,8.2017: wrong operation point (buffers not empty)

• B. Jaeger

– TCP BBR 7

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Mininet Setup

Sender Receiver Bottleneck Link Different RTTs

• B. Jaeger

– TCP BBR 8

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Parameters & Measurements

Parameters

• Congestion-Control algorithm per flow/host
• bottleneck-bandwidth & TBF parameters
• number of flows & individual RTT

Sender Receiver Bottleneck Link Different RTTs

• B. Jaeger

– TCP BBR 9

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Parameters & Measurements

Measurements

• tcpdump: throughput, RTT, fairness
• BBR values: btl_bw, rt_prop, pacing_gain
• B. Jaeger

– TCP BBR 10

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Next Steps

Find out how BBR works

• Implement Setup in Mininet
• Reproduce previous Results in Mininet
• Develop tool-chain to interpret Results

in progress Find meaningful Test Scenarios in progress Run final Tests Verify Results on Hardware Interpret Results

• B. Jaeger

– TCP BBR 11

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Related Work Sources:

• N. Cardwell, Y. Cheng, C. S. Gunn, S. H. Yeganeh, and V. Jacob-
• son. BBR: Congestion-Based Congestion Control. ACM Queue, 14,

September-October:20 – 53, 2016.

• S. Ma, J. Jiang, W. Wang, and B. Li. Towards RTT Fairness of Congestion-

Based Congestion Control.

• M. Hock, R. Bless, and M. Zitterbart. Evaluation of BBR Congestion

Control.

• B. Jaeger

– TCP BBR 12

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Intra-Protocol Fairness

Wireshark IO Graphs: s1

15 30 45 60 75 90 Time (s) 300000 600000 900000 1.2·10 6 1.5·10 6 1.8·10 6 Bits/100 ms

• 10 Mbit/s bottleneck-bandwidth
• 5 BBR flows each with 40ms RTT starting at intervals of 2s
• B. Jaeger

– TCP BBR 13

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

BBR vs CUBIC

Wireshark IO Graphs: s1

20 40 60 80 100 120 Time (s) 250000 500000 750000 1·10 6 1.25·106 1.5·10 6 Bits/100 ms

• CUBIC, BBR, 30ms RTT, 10Mbit/s
• TBF latency 300ms (large buffer)
• B. Jaeger

– TCP BBR 14

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

BBR vs CUBIC

Wireshark IO Graphs: s1

20 40 60 80 100 120 Time (s) 150000 300000 450000 600000 750000 900000 1.05·106 Bits/100 ms

• CUBIC, BBR, 30ms RTT, 10Mbit/s
• TBF latency 50ms (small buffer)
• B. Jaeger

– TCP BBR 15

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

BBR vs CUBIC

Wireshark IO Graphs: s1

20 40 60 80 100 120 Time (s) 200000 400000 600000 800000 1·10 6 1.2·10 6 Bits/100 ms

• CUBIC 30ms RTT, BBR 80ms RTT, 10Mbit/s
• TBF latency 50ms (small buffer)
• B. Jaeger

– TCP BBR 16