Improving Multipath TCP. PhD Thesis - Christoph Paasch

Transcription

1 Improving Multipath TCP PhD Thesis - Christoph Paasch

2 The Internet is like a map...

3 highly connected

4 Communicating over the Internet A 1 A A 2 A 3 A 4 A 5

5 Multipath communication A 1 A 2 A 3 A 4 A 5 A B B 6 B 7 B 8 B 9 B 10

6 Multipath communication A 1 A 2 A 3 A 4 A 5 A B B 6 B 7 B 8 B 9 B 10

7 Multipath communication A A 7 A 8 6 A 2 1 A 9 A 10 A B B 6 B 7 B 8 B 9 B 10

8 Multipath communication Faster communication (resource pooling) Seamless handover (resilience to failures)

9 Multipath TCP A 1 A 2 A 3 A 4 A 5 A B B 6 B 7 B 8 B 9 B 10

10 Multipath TCP Web-Server IP : A IP: B

11 Multipath TCP Dst: A Seq: 1 Dst: A Seq: 2 Dst: A Seq: 3 IP : A Dst: A Seq: 4 Web-Server Dst: B Seq: 8 IP: B Dst: B Seq: 5 Dst: B Seq: 6 Dst: B Seq: 7

12 Multipath TCP WiFi Dst: A Seq: 1 Dst: A Seq: 2 Dst: A Seq: 3 IP : A Dst: A Seq: 4 Web-Server Internet Dst: B Seq: 8 IP: B 3G/LTE Dst: B Seq: 5 Dst: B Seq: 6 Dst: B Seq: 7

13 Multipath TCP Dst: A Seq: 1 Dst: A Seq: 2 Dst: A Seq: 3 Dst: A Seq: 4 Web-Server Dst: B Seq: 5 Dst: B Seq: 6 Dst: B Seq: 7 Dst: B Seq: 8

14 Multipath TCP handshake Src: A, Dst: S SYN MPTCP: ID - X Src: S, Dst: A SYN + ACK MPTCP: ID - Y

15 Multipath TCP handshake Src: B, Dst: S SYN MP_JOIN: ID - Y Src: S, Dst: B SYN + ACK MP_JOIN

16 Transmit data with Multipath TCP Src: S Dst: A Src: S Dst: A Seq: 1 Seq: 2 write(...); 1 Src: S Dst: B Seq: 3 2 3

17 Multipath TCP Can Multipath TCP be used on the Internet? Performance? Can it be implemented? Could it be designed differently?

18 Improving Multipath TCP

19 Improving Multipath TCP Implementing Multipath TCP Evaluating Transport Protocols Multipath TCP in action"

20 Improving Multipath TCP Implementing Multipath TCP Evaluating Transport Protocols Multipath TCP in action"

21 Implementing Multipath TCP

22 Goals of the implementation 1. Minimize performance impact on regular TCP 2. Reduce complexity within regular TCP 3. Achieve high performance for Multipath TCP

23 Why a Linux Kernel implementation? Tightly integrated into the TCP-stack Best performance Reactive to changes in path characteristics

24 Implementing Multipath TCP and how it fits inside the Linux Kernel (based on a prototype from Sébastien Barré)

25 Architecture of Multipath TCP Application Layer User-Space standard Socket API Transport Layer Kernel-Space Multipath TCP send-queue receive-queue TCP subflow TCP subflow send-queue send-queue Network Layer

26 Data structures of regular TCP Application Layer socket tcp_sock MPTCP-layer subflow-layer Network Layer

27 Data structures of Multipath TCP Application Layer socket tcp_sock meta socket mptcp_tcp_sock MPTCP-layer mptcp_cb tcp_sock TCP subflow mptcp_tcp_sock Network Layer subflow-layer

28 Linux Kernel Multipath TCP and its performance compared to regular TCP

29 MPTCP performance with Apache 100 simultaneous HTTP-Requests, total of Gbps regular TCP 1 Gbps

30 MPTCP performance with Apache 100 simultaneous HTTP-Requests, total of Gbps TCP with linkbonding 1 Gbps

31 MPTCP performance with Apache 100 simultaneous HTTP-Requests, total of Gbps MultiPath TCP 1 Gbps

32 Improving Multipath TCP Implementing Multipath TCP Evaluating Transport Protocols Multipath TCP in action

33 Evaluating Transport Protocols

34 Evaluating Multipath TCP RTT Bufferbloat Capacity

35 Evaluating Multipath TCP RTT Bufferbloat Capacity RTT Bufferbloat Capacity

36 Evaluating Multipath TCP 8Mbps, 20ms Emulated WiFi/3G 2Mbps, 150ms How Hard Can It Be? Designing and Implementing a Deployable Multipath TCP. C. Raiciu, et al. NSDI 12

37 Evaluating Multipath TCP 3G/LTE 3G Access Provider (BE) Internet WiFi Residential Broadband (BE) Exploring Mobile/WiFi Handover with Multipath TCP. C. Paasch, et al. CellNet 12

38 Evaluating Multipath TCP 3G/LTE 3G Access Provider (US) Internet WiFi Residential Broadband (US) A Measurement-based Study of Multipath TCP Performance over Wireless Networks. Y.-C. Chen, et al. IMC 13

39 Evaluating Multipath TCP

40 Evaluating Multipath TCP

41 Experimental Design a scientific approach to evaluation

42 The planned approach to evaluation 1. Define the objective 2. Decide the factors 3. Design the experiment

43 Design the experiment Space-Filling Designs

44 Evaluating Multipath TCP s resource pooling using the Experimental Design approach

45 1. Objective Quantify Multipath TCP s resource pooling capabilities Aggregation Benefit 0 Mb/s -1 Same as best path 0 Perfect aggregation 1 Multipath Aggregation of Heterogeneous Access Networks. D. Kaspar. Phd Thesis. University of Oslo

46 2. Domains of the factors Capacity, RTT, Buffering Capacity, RTT, Buffering Low-BDP High-BDP Capacity 0.1 to 100 Mbps 0.1 to 100 Mbps RTT 0 to 50 ms 0 to 400 ms Buffering 0 to 100 ms 0 to 2000 ms

47 3. Experiment design 6-Dimensional Space ~200 parameter-sets in a space-filling design ~4 hours of experiments

48 Visualizing the output Outliers Lower/Upper Quartile Median

49 Congestion Control Detecting the link s capacity Loss-based (LIA) Delay-based (wvegas)

50 Resource Pooling (LIA) Design, Implementation and Evaluation of Congestion Control for Multipath TCP. D. Wischik, et. al. NSDI 2011

51 Resource Pooling (wvegas) Delay-based congestion control for Multipath TCP. Y. Cao, M. Xu, X. Fu. IEEE ICNP

52 Improving Multipath TCP Implementing Multipath TCP Evaluating Transport Protocols Multipath TCP in action

53 Multipath TCP Supported across a middleboxes Handover traffic from WiFi to 3G Generic Scheduling Infrastructure

54 Supported across middleboxes

55 Multipath TCP Supported across a middleboxes Handover traffic from WiFi to 3G Generic Scheduling Infrastructure

56 Scheduling Dst: A Seq: 1 Dst: A Seq: 2 Low-Delay Web-Server High-Delay Dst: A Seq: 3 Dst: A Seq: 4 Dst: A Seq: 5

57 Handover

58 High Performance Zero-copy support Flow-to-core affinity Hardware offloading supported

59 The fastest TCP connection 10 Gig Links

60 The fastest TCP connection

61 Conclusion

62 Conclusion It is scalable in the Linux Kernel Experimental Design allows to better evaluate transport layer protocols Works in action across the Internet

63 Conclusion Multipath TCP works mostly well in heterogeneous environments Possible design evolution for more flexibility

64 Thank you!