- - PowerPoint PPT Presentation

Architectures de Réseaux de Services

ClaudeChaudet (ENSTPARIS) (INRIA– CITI) Isabelle.GuerinLassous@inrialpes.fr

Context:QoS foradhocnetworks

Adhocnetworks

–

IEEE802.11

–

Mediumoverloaded

• Unpredictableuseofthe

radiomedium

QoS foradhocnetworks

–

Mechanismstoprovide guarantees

–

BRuIT [Chaudet andGuérin Lassous,EW2002]

• BandwidthReservation

underInTerferences

A B C D

Ad hoc network The 3 pairs scenario

BRuIT

• Shareofthemediumwith802.11

–

Carriersensingrange

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Twicethecommunicationrange

• Simulation/experimentation(at

2Mb/s)

• PrinciplesofBRuIT

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Routing+reservation

• Ondemand:AODVlike
• Floodingofarequest
• Admissioncontrol
• Replyonthereversepath+

reservation

–

Admissioncontrol

• Usedbandwidthpernode:allthe

trafficonthe2hopneighborhood

B C A

Communication range Carrier sensing range

A B C D E F G A B C D

Hello(A,B,C,D) Hello(A,B,C,D) Hello(A,B,C,D)

Whytwohops?

• Twohops≠ twicethe

communicationrange

• Howmanynodesareundetected?

–

Randomgeometricgraphs One hop - Max: 70 % Two hops - Max: 50 %

Whynotthreehops?

undetected Max: 48 % “Over-detected” Max: 40%

Evaluationof BRuIT

• Simulation

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NS2version2.27

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Randomgeometricgraphsfrom10to100nodes

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5to30flowsof80kbit/s

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Averageover100simulations

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ComparisonwithAODV

• Impactofadmissioncontrol
• Impactofguarantees
• AdmissionrateofBRuIT

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Between50%and60%comparedtoAODV

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Thedifferenceincreaseswiththenetworkload

• Establishmenttime

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Around100ms

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Between20%and40%slowerthanAODV

Evaluationof BRuIT

• Routelength

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Between50%and100%longerthantheshortestpath(AODV10% longerthantheshortestpath)

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LoadbalancewithBRuIT

• Signalingload

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Comparable

• BRuIT:Hellopackets
• AODV:Routereconstruction

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BRuIT morestable

• Allthecurvesareavailableinthepaper