A efficient bandwidth management scheme for realtime Internet applications

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A efficient bandwidth management scheme for
real-time Internet applications

• ??Fugui Wang,Prasant Mohapatra ,Sarit Mukherjee
  ,Dennis Bushmitch
• ??Computer Communications 25 (2002) 1596-1605
• ??????

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Outline

• Introduction
• Pipe
• Implementation of pipe
• Improving pipe utilization through updating
• Conclusion

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Introduction

• With the proliferation of multimedia and
  real-time applications ,it is becoming more
  desirable to provide certain QoS guarantee for
  Internet applications.
• Premium service is an ideal for real-time
  application such as IP telephony and video
  conferencing.

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Introduction

• A completely dynamic SLA could cause the problem
  about BBs scalability.
• BB has to maintain state of each arrive/depart
  flow.
• The SLA for premium service could update
  periodically that we can get better utilization
  than static SLA.

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Pipe

• Concept of a pipe
• It can perform an end-to-end QoS guarantee in
  DiffServ environment .
• It can be used to guarantee ingress-to-egress
  bandwidth availability without the overhead of
  per-flow maintenance.
• BB is involved only when the pipe capacity need
  to update.

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Pipe

• Definition of a pipe

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Pipe

• A pipe is defined as a logic path between two
  ends points.
• The purpose of a pipe is to reduce the signaling
  and computation overhead of BB and to achieve
  efficient bandwidth management.

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Pipe

• Relationship between pipe and SLA
• All traffic between ingress point A and egress
  point B.
• All of pipes configuration are stored in
  domains BB.
• Establishments of pipes
• The initial setup information includes ingress
  router, egress router and initial bandwidth,
  after setup the information is sent to BB of the
  domain from the ingress router.

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An end host want to make a connection to other
end host in domain2
?
BB
BB
OK ?
OK ?
OK !
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?
BB
BB
Ask BB to increase pipe capacity
No OK!
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Implementation of pipe
n0n3 core router Link n0-n1, n1-n2
,n2-n3 With link bandwidth 10M,5M,10Mbps
Simulation Topology
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Implementation of pipe

• This experiment used several queuing discipline
  in edge routers.
• Priority queue (PQ)
• Weighted fair queue (WFQ)
• Pick up one voice stream from the pipe between n0
  and n3 to study the voice packet delays and
  jitters.

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Improving pipe utilization through updating

• Pipe capacity can be set static or dynamic if
  its static, the admission control are done at
  entrance of pipe and we set the capacity as peak
  .
• It makes the utilization very low.
• If its dynamic ,BB received one update
• message upon each call arrive/departure.
• It makes the utilization could be 100
• but it greatly increases updating overhead.

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Improving pipe utilization through updating

• One possible solution is updating the pipe
  capacity periodically.
• So our goal is find a good prediction method to
  update the pipe capacity so that we can have
  both high utilization and acceptable updating
  overhead.

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Improving pipe utilization through updating
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Improving pipe utilization through updating

• Ideal prediction
• Based on updating points so we can precisely
  predict the peak bandwidth of next period.
• In fact, its impossible for real world because
  we are not aware of future events.

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Improving pipe utilization through updating
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Improving pipe utilization through updating

• Threshold-based prediction
• (1)Upon a call arrive , if number of calls reach
  the pipe_capacity , then pipe_capacity is
  increased by d.
• (2)Upon a call departure, if the numbers of calls
  is under pipe_capacity-2d ,then pipe_capacity is
  decreased by d.

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Improving pipe utilization through updating
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Improving pipe utilization through updating
Normalized_updates Number_of_updates ------------
---------------- 2 number_of_call.
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conclusion

• We can not get both 100 utilization and no
  updating overhead so we should choose the most
  adaptive situation among different scheme.