2. LYU9903 QoS Schemes in Wireless Networks Ho Pun Mo & Ng Maggie Supervised by Prof. Lyu R.T. Michael 6 December, 1999

3. Outline Introduction Wireless Networks QoS Performance Evaluation QoS in Wireless Networks Application - Video Future Work

4. Introduction Concern about QoS and wireless networks QoS is not as simple as one would think Platform we choose is Linux Focus on:  investigating and analyzing QoS schemes on wireless networks  measuring and comparing performance on wired/wireless networks

5. Wireless Networks Wireless Local Area Networks (Wireless LANs) Wireless Wide Area Networks (Wireless WANs)

6. Wireless LANs Extension to /Alternative for Wired Network IEEE 802.11 standard Using Radio Frequency (RF) connected as infrastructure network

7. Wireless LANs What is Infrastructure Network?

8. Wired vs Wireless Networks different physical & datalink protocols different hardware wireless networks: Roaming different performance

9. Why Wireless? Importance of Wireless LANs:  increasing of mobility Trend of Wireless LANs:  better performance  lower cost

10. Why Wireless? Applications of Wireless LANs:  in hospitals  in campus  in retail stores & restaurants  in warehouses  in old buildings

11. Wireless Devices Access Points: Proxim RangeLAN2 Ethernet & Token Ring Access Point WaveLAN WavePOINT-II Access Point

12. Wireless Devices PC Cards: WaveLAN Turbo(Bronze) PC CardProxim RangeLAN2 7400 PC Card Date Rate: 2-6 Mbps Range: 40-115m (indoor) 120-540m (outdoor) Freq.: 2400-2483.5MHz Date Rate: 1.6 Mbps Range: 152m (indoor) 305m (outdoor) Freq.: 2.4GHz

13. Pros & Cons of Wireless Advantages:  Mobility  Flexibility  Ease of Installation  Cost of Installation  Security  Enough Bandwidth for Office Uses

14. Pros & Cons of Wireless Disadvantages:  Low Bandwidth  High Error Rates & High Delay  Limited Range of Coverage  Large Consumption of Battery  Unwanted Interference

15. What is QoS? There are many QoS’s We concern about QoS in computer networks Some definitions:  the collective effect of service performances which determine the degree of satisfaction of a user of the service  the ability of a network to deliver time-bounded traffic types (e.g. real time video or voice) with predictable latencies  a way to specify an applications network performance requirements, and it is specified by performance parameters

16. What is QoS? What QoS means to us: QoS is the guarantee of delivering network packets punctually and the guarantee of delivering an acceptable numbers of network packets in a compromised time interval, which would not annoy the receivers.

17. Why QoS? Statistic from Cisco shows that multimedia applications become more and more popular

18. Why QoS? Which one do you prefer? NormalLong DelayLost Frame

19. How to Achieve QoS? Many ways Bandwidth reservation + Packet scheduling Bandwidth reservation RSVP Packet scheduling CBQ

20. How to Achieve QoS? ~ Bandwidth Reservation RSVPRSVP is a protocol that allows channels or paths on the networks to be reserved for the transmission of video and other high- bandwidth messages.

21. How to Achieve QoS? ~ RSVP

22. How to Achieve QoS? ~ Packet Scheduling There are many packet scheduling algorithms Some examples:  FIFO - First In First Out  SFQ - Stochastic Fairness Queuing  WFQ - Weighted Fair Queuing  CBQ - Class Based Queuing Focus on CBQ

23. How to Achieve QoS? ~ CBQ Hierarchical link-sharing structure

24. Architecture ~ Combining RSVP and CBQ       Server Client

25. Performance Evaluation ~ Wired Networks Scenario: ServerClient Ethernet Application: FTP Application: MP3 player

26. Performance Evaluation ~ Wired Networks Results with & without QoS

27. Performance Evaluation ~ Wired Networks Applied QoS & NoQoS in same experiment noqosqos

28. Performance Evaluation ~ Wired Networks What can you see from the results?  QoS makes MP3 playing smoothly  QoS benefits both MP3 and FTP applications  QoS can be applied on the fly

29. Performance Evaluation ~ Wireless Networks Scenario: Server Client Ethernet Application: FTP Application: MP3 player Access Point

30. Performance Evaluation ~ Wireless Networks Performance on using the Proxim devices

31. Performance Evaluation ~ Wireless Networks Performance on using the WaveLAN devices

32. Performance Evaluation ~ Wireless Networks With / without QoS in the same experiment Received Bandwidth of FTP & MP3 with 200Kbits (using Proxim) Received Bandwidth of FTP & MP3 with 200Kbits (using WaveLAN) noqos qos

33. Performance Evaluation ~ Wireless Networks What can you see from the results?  QoS makes MP3 playing smoothly  QoS benefits both MP3 and FTP applications  Wired Networks vs Wireless Networks: Wireless Networks have larger delay  Proxim vs WaveLAN: seems Proxim performs better!

34. QoS in Wireless Networks Problems:  Variable bandwidth  Roaming  Low Reliability and Long Delay  Interference  Hard disk bottleneck Solutions:  Renegotiation  Apply QoS in Access Points  Network Collision Control

35. Application - Video Real time video player for both wired and wireless networks with QoS enabled Design:  RPC  Enabled QoS  Buffering at both client and server side  RAPI

36. Future Work Measure the delay jitter of the QoS systems (both wired and wireless) Measure the performance of the QoS systems with router presented Finish our video application with QoS enabled Measure the performance of our video application Inspect the source code of WaveLAN driver in order to make it QoS enabled

37. The End Thanks!