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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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Blip meeting agenda
BLIP Meeting - Agenda at BLIP Systems

  • 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)


Implementation and evaluation of a performance enhancing proxy for wireless tcp

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


Agenda
Agenda Proxy for Wireless TCP

  • 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


Goal of this project
Goal of this project Proxy for Wireless TCP

  • 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


Considered scenarios
Considered Scenarios Proxy for Wireless TCP

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


Short reminder tcp
Short Reminder - TCP Proxy for Wireless 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


Evaluation

Evaluation Proxy for Wireless TCP


Evaluation measurement procedure
Evaluation – Measurement Procedure Proxy for Wireless TCP

  • 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)


Evaluation metrics
Evaluation - Metrics Proxy for Wireless TCP

  • Instantaneous Throughput

  • Instantaneous Averaged Throughput

  • Transmission Throughput

  • Round-Trip-Times (RTT)


Single connection over bluetooth scenario
Single Connection over Bluetooth - Scenario Proxy for Wireless TCP

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


Single udp connection over bluetooth
Single UDP Connection over Bluetooth Proxy for Wireless TCP


Single udp connection over bluetooth1
Single UDP Connection over Bluetooth Proxy for Wireless TCP


Single tcp connection over bluetooth
Single TCP Connection over Bluetooth Proxy for Wireless TCP


Single tcp connection over bluetooth1
Single TCP Connection over Bluetooth Proxy for Wireless TCP


Single tcp connection over bluetooth2
Single TCP Connection over Bluetooth Proxy for Wireless TCP

  • 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)


Additional results
Additional Results Proxy for Wireless TCP

  • 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)


Conclusions questions
Conclusions - Questions Proxy for Wireless TCP

  • 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


References
References Proxy for Wireless TCP

  • 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:

    [email protected]


Thanks for listening! Proxy for Wireless TCP

Any Questions?

Yes, i have some...


Questions
Questions Proxy for Wireless TCP

  • 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?


Backup

Backup Proxy for Wireless TCP


Adhoc udp connection over bluetooth
Adhoc UDP Connection over Bluetooth Proxy for Wireless TCP

  • 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





Adhoc tcp connection over bluetooth
Adhoc TCP Connection over Bluetooth Proxy for Wireless TCP

  • 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



Adhoc tcp connection over bluetooth1
Adhoc TCP Connection over Bluetooth Proxy for Wireless TCP


Current iplab network architecture
Current IPLab network architecture Proxy for Wireless TCP

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


Single tcp connection over bluetooth scenario
Single TCP Connection over Bluetooth - Scenario Proxy for Wireless TCP

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



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