Improving TCP performance over mobile networks

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Improving TCP performance over mobile networks

• ACM Computing Surveys (CSUR),Volume 34 , Issue 3
  (September 2002)

Presenter Tzvi Ben-David I.D. 01300478 January
2003
System Analysis and Design Article Summary
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Introduction

• Mobile users would like to use the same
  applications over the wireless link and with the
  same quality of service (QoS) they are getting
  over a wired link.
• Objective to improve the performance of TCP over
  mobile wireless networks.

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Regular TCP and Mobility

• TCPs main problem is the delay caused by packet
  losses due to congestion.
• Wired links have low bit error rates (BER), as
  opposed to wireless links that suffer from high
  bit error rates.
• If regular TCP is used on a mobile network, it
  can severely degrade performance.

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Wired Link ver. Wireless Link

• The wired link has a bandwidth of 1.5 Mb and a
  delay of 10 ms, while the wireless link has a
  bandwidth of 0.8 Mb and delay of 100 ms.

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Effect of BER on Performance of TCP
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Protocols to Improve the Performance of TCP on
Mobile Networks

• Link Layer Protocols.
• End-to-End Protocols.
• Split-Connection Protocols.

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Summary
The following is a summary table of the problems
handled in the various proposed protocols
mentioned above
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Conclusions

• Avoid erroneously triggering congestion control
  mechanisms on the fixed host.
• Avoid the serial timeout problem on the fixed
  host.
• Be reliable, by solving the problems arising from
  the lossy wireless links and their bursty high
  BER.

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Conclusions (2)

• Can efficiently deal with handoff.
• Can handle frequent and long disconnections of
  the mobile host.
• Take into consideration the limited bandwidth and
  power scarcity of mobile hosts.

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Conclusions (3)

• Use a dynamic packet size depending on the
  dynamic bandwidth available for mobile hosts.
• Provide end-to-end semantics of TCP.
• Preferably provide compatibility that is, do not
  require any software on the fixed hosts.

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Thank you for your attention!