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Presentation of Bluetooth Activities of Aalborg University at BLIP Systems

Presentation of Bluetooth Activities of Aalborg University at BLIP Systems. BLIP Meeting - Agenda. Agenda: Preliminary Results of TCP Performance over Bluetooth (Dennis Dungs, ca. 30 min) Location Information in Bluetooth (Joao Figueiras, ca. 30 min)

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Presentation of Bluetooth Activities of Aalborg University at BLIP Systems

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  1. Presentation of Bluetooth Activities of Aalborg University at BLIP Systems

  2. BLIP Meeting - Agenda • Agenda: • Preliminary Results of TCP Performance over Bluetooth (Dennis Dungs, ca. 30 min) • Location Information in Bluetooth (Joao Figueiras, ca. 30 min) • Scatternet Formation (Istvan Kovacs, ca. 30 min) • Set-up of experimental Bluetooth network at Aalborg University(who??, 10 min) • Bluetooth simulation tools (who??, 10 min)

  3. Implementation and Evaluation of a Performance Enhancing Proxy for Wireless TCP Master Thesis Project (Sep 03 – April 04) Dennis Dungs Technical University Munich, Germany Aalborg University, Denmark March 2004 Supervised by Hans-Peter Schwefel Aalborg University, Denmark

  4. Agenda • Goal and steps of this project • Considered Scenarios in the project • Short Reminder: TCP • Evaluation of Bluetooth Performance • UDP in Single MN AP Scenario • TCP in Single MN AP Scenario • Conclusions

  5. Goal of this project • Goal: • Identify TCP performance lacks in wireless scenarios • Evaluate performance capabilites of a TCP Proxy • Steps • Getting familiar with concepts of TCP • Research about common TCP implementations • Describing wireless scenarios • Analyzing TCP performance and Identifying TCP performance lacks in wireless scenarios • Designing and Implementing a TCP Proxy • Evaluation of Scenarios using the TCP Proxy

  6. Considered Scenarios Wireless supporting Network Proxy Wired Network Mobile Host Server • Definition: „A Scenario consists of a description of the network infrastructure, mobility model and traffic model.“ • Network Infrastructure: • Access Technology • Proxy Location • Sender / Receiver Location • Network configuration • Mobility Model • Fixed position • Handover to same/different subnet • Handover to new access technology • Traffic Model • Size of transmitted data • Used bandwith • Single-/Multi-User • Cross-traffic • Constant / Burst Traffic

  7. Short Reminder - TCP • Goals of TCP: • Connection oriented, full duplex protocol • Multiplexing of IP-datagram service (Ports) • In-order data transfer (Sequence Numbers) • Reliable data transfer (Acknowledgements) • Prevent Receiver from flooding (Receiver Advertised Window) • Prevent intermediate systems from flooding (Congestion Control Algorithm) • Congestion Control • Congestion Window: Number of bytes, that can be send in one RTT without congestion • Dynamically adjusted until congestion indicated via DUPACKs or timeouts • Exponential increase per RTT to reach maximum throughput (slow-start) • Continuous probing of maximum available bandwith via linear increase/ multiplicative decrease per RTT

  8. Evaluation

  9. Evaluation – Measurement Procedure • IPerf • Setup a UDP/TCP connection from sender to receiver • Send data from sender to receiver at maximum bandwidth (TCP) or given bandwidth (UDP) • Ethereal • Trace Ethernet packets at sender and receiver in real-time into a file • Traces arrival times of packets t(n) and contents of Ethernet packets • TCPTrace • Generate TCP Statistics offline • Matlab • Generating UDP Statistics offline • Calculating statistical parameters • GNUPlot • Visualizing TCP Statistics (RTT Graphs, Throughput Graphs)

  10. Evaluation - Metrics • Instantaneous Throughput • Instantaneous Averaged Throughput • Transmission Throughput • Round-Trip-Times (RTT)

  11. Single Connection over Bluetooth - Scenario Delft China Aalborg Shanghai Toronto Network Setup: • Scenario Parameters: • MN: 2.6 GHz-P4 512MB RAM, WinXP, Belkin Class2 BT USB Adapter • AP: BlipNet BlipNode L1 • Supposed Master: AP • Supposed Slave: Mobile Node • Application Profile: PAN • Distance AP->MN: 1m • Server: PPro 166Mhz, 32MB RAM, running Redhat 7.3 • Sending duration: 30sec • UDP payloadsize: 1470 bytes • UDP Bandwith: 700kBit/s (Application Layer Bandwith) • TCP receiver buffer: 8 kBytes 8 MBit/s 8 MBit/s Tokyo 100 MBit/s 100 MBit/s 100 MBit/s 100 MBit/s Server 10.10.3.254 10.10.1.X Downstream Mobile Node Legend: Router Switch BT AP Fixed Host Mobile Host

  12. Single UDP Connection over Bluetooth

  13. Single UDP Connection over Bluetooth

  14. Single TCP Connection over Bluetooth

  15. Single TCP Connection over Bluetooth

  16. Single TCP Connection over Bluetooth • Possible Reasons for throughput jumps • Traffic in low-bandwidth direction (Routers) • Packet Scheduler has to send more data • Adjusting to „more symmetric“ bandwidth • Flow Control on Baseband • Interference • Channel quality driven data rate change (CQDDR)

  17. Additional Results • Upstream (Slave->Master) gains always higher throughput than downstream • Adhoc – Scenario: • Same throughput jumps (UDP & TCP) as in AP-scenario, but less likely • Higher average throughput • No significant differences between WinXP (WidComm-Stack) and Linux (BlueZ-Stack)

  18. Conclusions - Questions • Conclusion: • Many factors could cause the throughput-dropdown • Difficult to analyze TCP performance lacks, if underlying behaviour unclear • To get deeper understandings, packet trace tool for Baseband is needed

  19. References • Project WebSite: http://kom.aau.dk/~dennis/ • IPLab WebSite: http://kom.aau.dk/iplab/ • RFCs : RFC791 (IP), RFC793 (TCP), a.o. http://www.ietf.org/ • Bluetooth Specification http://www.bluetooth.org/ • eMail: dennis@kom.aau.dk

  20. Thanks for listening! Any Questions? Yes, i have some...

  21. Questions • How to figure out, which Bluetooth device is master, which is slave (role switching)? • How to figure out, which packet types are used (DM, DF, AUX) ? • How to figure out, if master/slave uses „Channel quality driven data rate change” and when it affects the channel • How to figure out, how “Flow Control” on baseband level is influencing the throughput? => Is it possible to trace packets at Baseband level?

  22. Backup

  23. Adhoc UDP Connection over Bluetooth • Scenario Parameters • MN 1: 2.6 GHz-P4 512MB RAM, WinXP, Belkin Class2 BT USB Adapter • MN 2: 266MHz-P 64MB RAM, WinXP, Belkin Class2 BT USB Adapter • Supposed Master: MN 1 • Supposed Slave: MN 2 • Application Profile: PAN • Distance MN1->MN2: 1m • Sending duration: 10sec • UDP payload-size: 1470 bytes • UDP Bandwith: 700kBit/s (Application Layer Bandwith) Mobile Node 2 (supposed Slave) Mobile Node 1 (supposed Master) UDP Downstream UDP Upstream

  24. Adhoc UDP Connection over Bluetooth - Downstream

  25. Adhoc UDP Connection over Bluetooth - Upstream

  26. Adhoc UDP Connection over Bluetooth - Comparison

  27. Adhoc TCP Connection over Bluetooth • Scenario Parameters • MN 1: 2.6 GHz-P4 512MB RAM, WinXP, Belkin Class2 BT USB Adapter • MN 2: 266MHz-P 64MB RAM, WinXP, Belkin Class2 BT USB Adapter • Supposed Master: MN 1 • Supposed Slave: MN 2 • Application Profile: PAN • Distance MN1->MN2: 1m • Sending duration: 10sec • Standard WinXP TCP Implementation • TCP Window Size: 8kByte Mobile Node 2 (supposed Slave) Mobile Node 1 (supposed Master) TCP Downstream TCP Upstream

  28. Adhoc TCP Connection over Bluetooth – Comparison US/DS

  29. Adhoc TCP Connection over Bluetooth

  30. Current IPLab network architecture IP LAB: Current Architecture Aalborg Shanghai Internet Toronto 10.10.2.254 Istanbul 10.10.3.254 10.10.4.2 10.10.254.254 10.10.3.1 San Francisco 130.225.51.6 Tokyo Frankfurt Delft GPRS Network 10.10.2.1 10.10.1.1 Toronto Shanghai 10.10.1.254 10.10.1.2 10.10.2.2 Sydney Dhaka

  31. Single TCP Connection over Bluetooth - Scenario Delft China Aalborg Shanghai Toronto Network Setup: • Scenario Parameters: • MN: 2.6 GHz-P4 512MB RAM, SuSE Linux 9.0 (Kernel 2.4.21-166), BlueZ Stack (Lib 2.5, SDP 1.5, PAN 1.1) • AP: BlipNet BlipNode L1 • Master: AP • Slave: Mobile Node • Application Profile: PAN • Distance AP->MN: 1m • Server: PPro 166Mhz, 32MB RAM, running Redhat 7.3 • Sending duration: 30sec • Standard TCP Implementations • TCP Window Size: 8kByte 8 MBit/s 8 MBit/s Tokyo 100 MBit/s 100 MBit/s 100 MBit/s 100 MBit/s Server 10.10.3.254 10.10.1.X Mobile Node Legend: Router Switch BT AP Fixed Host Mobile Host

  32. Single TCP Connection over Bluetooth (Linux)

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