1. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 Department of Information Engineering University of Padova, ITALY On Providing Soft-QoS in Wireless Ad-Hoc Networks {andrea.zanella, daniele.miorandi, silvano.pupolin}@dei.unipd.it Andrea Zanella, Daniele Miorandi, Silvano Pupolin, Paolo Raimondi WPMC 2003, 21-22 October 2003 Special Interest Group on NEtworking & Telecommunications

2. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 Outline of the contents  Motivations & Purposes  Soft-QoS & Call Admission Control  Path creation & maintenance  Results  Conclusions

3. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 What & Why… Motivations & Purposes

4. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 Motivations  Ad-hoc networks are a valuable solution to  Extend in a multi-hop fashion the radio access to wired networks  Interconnect wireless nodes without any fixed network structure  In these contexts, providing QoS is a key issue  audio/video streaming  interactive games  multimedia  Classic QoS support methods involve  QoS-routing  Call-Admission-Control (CAC) mechanisms  MAC-layer Resource Reservation (MRR) strategies

5. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 Aim of the study Soft-QoSlow-profile  Providing basic Soft-QoS support over low-profile ad-hoc wireless networks Soft QoS  No hard QoS guarantees  Soft QoS modified AODV  Simple QoS routing algorithm  modified AODV distributed statistical CAC  Simple CAC mechanism  distributed statistical CAC statistical MRR  No static MRR  statistical MRR

6. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 Introduction to QoS issues Soft QoS & CAC

7. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 Hard & Soft QoS  Widely used in wired networks  Integrated Services: flow based (RSVP)  Differentiated Services: class based  Suitable for wireless networks  Applications may work even if, for short periods of time, QoS requirements are not satisfied  Deal with limited bandwidth and radio channel Hard-QoS Soft-QoS

8. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003  QoS parameters required per link  Minimum peak band: B r  End-to-End Delay: D r Target Satisfaction index  Soft QoS parameter: Target Satisfaction index   r = percentage of pcks expected to satisfy QoS constrains  r = 1  hard QoS  r = 0  pure best-effort  Path Service Levels P = (p 1,…, p N )  Path Peak Bandwidth  Path Delay Soft-QoS parameters

9. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 Call-Admission Control  Path is feasible if  Bandwidth constrained requests  Delay constrained requests  Using Gaussian approx, Bandwidth and Delay statistic is determined by mean and standard deviation  Bandwidth constrained requests  Delay constrained requests

10. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 Statistical Resource Reservation  Bandwidth-constrained  Delay-constrained  Extra-delay margin given to each link along the path is inversely proportional to the mean link delay  Resource bounds  Minimal residual resources that should be guaranteed to preserve QoS levels of accepted connections Actual SatisfactionResource bounds

11. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 Path creation & maintenance  Soft-QoS routing is largely inspired to AODV  Each Route Request (RREQ) packet gathers statistical information on the minimum bandwidth and maximum delay along that portion of the path  RREQ is propagated only whether bandwidth request is satisfied  The destination node back propagates a Route Reply (RREP) packet along the selected path  RREP acquaints intermediate nodes with new resource bounds and updates maximum sustainable traffic rate  Source node is required to respect the maximum sustainable traffic rate limit or to refuse the connection

12. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 Simulation Results Simulation of Soft-QoS routing algorithm

13. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 Simulation Scenario  Bluetooth Scatternet  Round Robin Polling  Gateways spend 50 slots in each piconet  Poisson packets arrival process  Mixed packet formats with average length of 1500 bits  Delay-constrained requests

14. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 Gaussian Approximation  Local slave-to-slave connections in each piconet  Data rate=9.6 Kbit/s  1 hop  6 hops fairly close  Gaussian approx is fairly close to empirical delay CDF  Gap increases for long-distance and high traffic connection

15. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 Simulation setup  Target connection c 1  D r = 50 ms   r = 0.2  r = 20 kbit/s  Target connection c 2  D r = 200 ms   r = 0.9  r = 30 kbit/s  Target connection c 3  D r = 200 ms   r = 0.9  r = 20 kbit/s  Target connection c 4  D r = 50 ms   r = 0.2  r = 60 kbit/s  Transversal connections  Starting after 20 s, last for 10 s  On average 1 request/s  Random source, destination & QoS requests  Rate: 5  20 kbit/s

16. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 Satisfaction & Delay dynamics  Satisfaction  Delay

17. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 Conclusions  We have proposed a basic Soft QoS routing algorithm for low-profile ad hoc networks  Provides Soft-QoS guarantees  Requires basic nodes’ functionalities statistical link state monitoring (mean and standard deviation)  Does not require service differentiation static resource reservation  Drawbacks  Lower resource utilization  Higher rate of connection request rejection

18. WPMC 2003 Yokosuka, Kanagawa (Japan) 21-22 October 2003 Department of Information Engineering University of Padova, ITALY On Providing Soft-QoS in Wireless Ad-Hoc Networks {andrea.zanella, daniele.miorandi, silvano.pupolin}@dei.unipd.it Andrea Zanella, Daniele Miorandi, Silvano Pupolin, Paolo Raimondi WPMC 2003, 21-22 October 2003 Special Interest Group on NEtworking & Telecommunications