High Speed Networks and Internets: Multimedia Transportation and Quality of Service

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Objectives. What is required to transportLarge volumes of trafficWith different QoS requirementsOver networks operating at very high data rates. The Need for Speed and QoS. Emergence of high-speed LANsExplosive growth of processing power of personal computersNetwork computingExamples of requir

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High Speed Networks and Internets: Multimedia Transportation and Quality of Service

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1. High Speed Networks and Internets: Multimedia Transportation and Quality of Service

2. Objectives What is required to transport Large volumes of traffic With different QoS requirements Over networks operating at very high data rates

3. The Need for Speed and QoS Emergence of high-speed LANs Explosive growth of processing power of personal computers Network computing Examples of requirements that calls for HSL Centralized server farms Power workgroups High-speed local backbone Examples of HSL: Fast Ethernet, Gigabit Ethernet, High speed wireless LAN, ATM LAN

4. The Need for Speed and QoS Corporate Wide Area Networking needs Intranet computing among dispersed employees Internet access with graphical interfaces Huge volumes of data with unpredictable traffic patterns

5. The Need for Speed and QoS Digital electronics Digital Video Disk (DVD) Huge storage capacity and vivid quality PC games and educational software with more video New crest of traffic over the Internet and intranets as the material is incorporated into web sites Digital still camera Convenience for use in networks Dramatic growth in the amount of on-line image and video traffic

6. The Need for Speed and QoS QoS on the Internet Internet and IP were designed to provide best-effort delivery service With tremendous increase in traffic volume, and the introduction of new real-time, multimedia, and multicasting application, the traditional Internet services are woefully inadequately

7. The Need for Speed and QoS QoS requirements of Internet applications Elastic traffic Email, file transfer, network management, interactive applications(rlogin, web access) Inelastic traffic Voice and video Throughput, delay, delay variance, packet loss Figure 0

9. QoS in IP Networks Design requirements Control congestion Provide low delay Provide high throughput Support QoS Provide fair service

10. QoS in IP Networks Two complementary architectures Integrated services Differentiated services Protocols for QoS support RSVP: support the IS architecture by enabling the reservation of resources in a datagram environment MPLS: framework for labeling traffic and routing based on traffic flows RTP: transport level support for real-time application

11. Integrated Services Architecture (ISA) Tools for controlling congestion in IP-based internet Routing algorithm Packet discard ISA approaches Admission control Routing algorithm Queueing discipline Discard policy

12. Integrated Services Architecture (ISA) ISA components Background functions Reservation protocol Admission control Management agent Routing protocol Main task: forwarding of packets Classifier and route selection Packet scheduler Figure1

14. Integrated Services Architecture (ISA) ISA services Guaranteed Assured capacity level or data rate Specified upper bound on the queueing delay through the network No queueing losses Controlled load Approximates the behavior with the best-effort service under unloaded conditions No specified upper bound on the queueing delay, but supposed to impose almost no queueing delay Almost no queueing loss Best effort

15. Integrated Services Architecture (ISA) Traffic description: Tspec

16. Integrated Services Architecture (ISA) Queueing discipline FIFO No special treatment for higher priority or delay sensitivity Inefficiency when smaller packets are queued behind a long packet Greediness is not punished Figure 3

18. Integrated Services Architecture (ISA) Queueing discipline Fair Queueing Processor Sharing Bit-Round Fair Queueing Generalized Processor Sharing Weighted Fair Queueing

19. Integrated Services Architecture (ISA) Discard policy Random Early Detection (RED) design goals Congestion avoidance Global synchronization avoidance Avoidance of bias against bursty traffic

20. Integrated Services Architecture (ISA) RED algorithm (Figure 4)

22. Differentiated Services (DS) DS configuration and operation:

23. Differentiated Services (DS) Per-Hop Behavior (PHB) Expedited Forwarding PHB: appears to the end points as a point-to-point connection or leased line Assured Forwarding PHB: a service superior to best-effort

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