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Agenda

QoS Support in MANETs: A Modular Architecture Based on the IEEE 802.11e Technology C. T. Calafate , M. P. Malumbres , J. Oliver, J. C. Cano & P. Manzoni presented by Visva Priya Mohanakrishnan Trilok Jain. Agenda. Introduction Related Work Proposed Architecture

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Agenda

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  1. QoS Support in MANETs: A Modular Architecture Based on the IEEE 802.11e TechnologyC. T. Calafate, M. P. Malumbres, J. Oliver, J. C. Cano & P. Manzoni presented byVisvaPriyaMohanakrishnanTrilok Jain

  2. Agenda • Introduction • Related Work • Proposed Architecture • Specifics of the Architecture • Experiments & Results • Conclusion

  3. Introduction • MANET – Mobile ad hoc networks • Collection of wireless mobile nodes • Multihop routing service • Self-reconfiguration • Limitations • Power • Traffic load • Noise and Attenuation (physical layer) • Hidden and exposed node problems (MAC layer) • Network topology changes (network layer) • MANET aware applications (app layer)

  4. Related Work • Set priorities(size of Contention Window) • Select route with sufficient resources • Resource-reservation based routing • MIMO antennas • QAOMDV + ETDMA Proposed Work • IEEE 802.11e technology • Access Categories • Voice, Video, Best Effort and Background • IP TOS to MAC priorities • EDCF

  5. QoS Architecture

  6. DACME

  7. DACME…. • Distributed Access Control Element • QoS measurement module • Assess QoS parameters • Packet filter • Block all unaccepted traffic • Method • Applications register with DACME • QSPEC – BR , DR , JR • Per source information table(destination) • Port State Table(source)

  8. DACME…. • Interaction with Routing Protocols • RREP • Multipath DSR • Interaction with IEEE 802.11e Layer • Probing packets with Video Access Priority • Contention-free bursting turned off

  9. Support for QoS

  10. QoS (BR, DR, JR) Framework of DACME • Bandwidth Probing • Delay Probing • Jitter Probing • Probes are done in this sequence

  11. Bandwidth Probing • Mechanism to determine Available Bandwidth at the destination site • n equal sized packets are sent to Destination • Inter Arrival Time (AIT) = Δt / n – 1 • Bandwidth = 8*packet_size / AIT bits/second • Source decides whether to accept the connection based on Bandwidth reply

  12. Bandwidth Probing (contd.) • Probe Size Tuning - optimum Number of Packets per Probe (n) • More packets means more accuracy but more overhead • Bandwidth Refinement • Correction Processes

  13. Probe Size Tuning • System Constraints • Factors on which Inter Arrival Time depends • End-to-End path congestion (c) • Number of Hops in the path (h) • Number of Packets per probe (n)

  14. Probe Size Tuning (contd.) Experimental Scenario for the Tuning Process

  15. Probe Size Tuning - Results n = 10

  16. Bandwidth Refinement • Done by multiple probes • Each successive probe updates the mean and standard deviation values for the Bandwidth • Bandwidth is refined iteratively

  17. Admission Control • Decision for accepting, maintaining or refusing a connection • After receiving Bi, • Calculate the new Bandwidth Estimator B’ • If B’ > BR -> Accept • If B’ < BR -> Reject ( with 95 % confidence level) Repeat for Nmax times

  18. Delay Probing • Consecutive request_probe/reply_probes needed to access delay • Calculate the average delay (De(0)) • Calculate the predicted delay using • An estimation function (a function of Path Utilization) • De(0)

  19. Delay Probing (contd.) If Bandwidth Constrained/ Blocked Traffic • dmin = D’e(umin) * De(0) • dmax = D’e(umax) * De(0) else • dmin = 0.9 * De(0) • dmax = 1.1 * De(0) Accept if dmax < DR, Reject if dmin > DR Repeat

  20. Jitter Probing • Source sends packets with same size, ToS field, data rate as the application • Destination calculates the standard deviation for jitter and replies • In case, packets from application are flowing, they can be used

  21. Jitter Probing (contd.) If • 2.1 * SD < JR : ACCEPT • 1.9 * SD > JR : REJECT • Duration of Probing Period • Depends on Bandwidth Available • Source Load

  22. Routing in MANETs • Required for Optimum Performance • Highly responsive to Interruptions • Should detect Path Losses • Should be able to find new Paths ASAP • MDSR – Multipath Extension to DSR • Integration of route discovery & assignment • Maximum path disjointness under low additional routing load

  23. MDSR • Consecutive paths used are disjoint most of the time • Additional route requests are propagated if their route lengths <= first route request

  24. Experiments

  25. Segregation of QoS traffic from Best Effort Traffic using IEEE 802.11e

  26. Segregation of QoS traffic from Best Effort Traffic using IEEE 802.11e….

  27. Segregation of QoS traffic from Best Effort Traffic using IEEE 802.11e…….

  28. Reducing the impact of Routing using Multipath Routing

  29. Reducing the impact of Routing using Multipath Routing……

  30. Application level QoS support through Distributed Admission control

  31. Application level QoS support through Distributed Admission control…

  32. Application level QoS support through Distributed Admission control…

  33. Application level QoS support through Distributed Admission control…

  34. Conclusions • The new Architecture overcomes the effects of congestion and mobility in MANETs • Able to quickly respond to topology changes • Is easily deployable • Can maintain a continuously high Video throughput and low delays • Probing packets do not affect the performance of sessions negatively

  35. Thank you !!! 

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