1 TTM5 Networked Services and Multimedia Systems, advanced Professor Peter Herrmann/ Postdoc Hien Nam Le Dept. Telematics (ITEM) University of Science and Technology (NTNU) Rm A277

2 Introduction Objective –This course shall give in-depth knowledge of principles, frameworks, and languages used for providing multimedia services over networks. Contents –SOA & Multimedia Systems –Multimedia tools and frameworks for providing multimedia services Framework and architecture Service discovery and delivery Deployment and management Other issues: mobility, location-based, transaction services

3 Introduction Recommended background –Communication - Services and Networks (TTM4100) –Access and Transport Networks (TTM4105) –Network Intelligence and Mobility (TTM4130) –Internet network architecture or equivalent (TTM4150). –Service and Resource Management (TTM 4128) Assessment –Oral or writing examinations –Date: 03 Dec 2007 Questions/requests – or walk-in rm A277

4 Schedule 7 two-hours seminars WeekDateTopics Introduction & review Guest lecture: Open Mobile Services Lecturer: Prof. Do, van Thanh

5 Topics Introduction, review and background on multimedia systems and network services –Multimedia systems –Service-oriented architecture Framework and architecture for developing multimedia services Discovery and delivery of multimedia services Deployment and management of multimedia services Other issues –Location-based services, mobility, transaction services

6 An overview picture Example –Develop a movie information service Requirements

7 An overview picture Live Free or Die Hard John McClane takes on an Internet-based terrorist organization who is … Text Photos Video clip Multimedia System Storage Presentation Search and retrieval

8 An overview picture Multimedia System/ Application Tools, framework, architecture Development Clients Interactions

9 An overview picture Multimedia Services Service Clients Services Multimedia System/ Application Clients Interactions Service-oriented Computing/ Service-oriented Architecture Service provider Service clients Service registry Publishing Finding Binding

10 Course materials Introduction, review and background –G. Coulouris, J. Dollimore, T. Kindberg: Distributed Systems: Concepts and Design, Chapter 15: Distributed Multimedia System –Mike P. Papazoglou: Service-Oriented Computing: Concepts, Characteristics and Directions. WISE 2003: 3-12 –Michael N. Huhns, Munindar P. Singh: Service-Oriented Computing: Key Concepts and Principles. IEEE Internet Computing 9(1): (2005) –Jilles van Gurp, Anssi Karhinen, Jan Bosch: Mobile Service Oriented Architectures (MOSOA) Additional reading –Donald F. Ferguson, Marcia L. Stockton: Service-oriented architecture: Programming model and product architecture. IBM Systems Journal 44(4): (2005) –Mark Little: Transactions and Web services. Commun. ACM 10(43) (2003) –Gerald C. Gannod and Janet E. Burge and Susan D. Urban: Issues in the Design of Flexible and Dynamic Service-Oriented Systems. SDSOA '07: Proceedings of the International Workshop on Systems Development in SOA Environments

11 Course materials Framework and architecture –Jia Zhang, Jen-Yao Chung: An open framework supporting multimedia web services. Multimedia Tools Appl. 30(2): (2006) –Vassilios N. Koukoulidis, Mehul Shah: The IP multimedia domain: service architecture for the delivery of voice, data, and next generation multimedia applications. Multimedia Tools Appl. 28(1-2): (2006) –Ahmet Uyar, Wenjun Wu, Hasan Bulut, Geoffrey Fox: Service-Oriented Architecture for Building a Scalable Videoconferencing System, in book "Service-Oriented Architecture - Concepts & Cases" published by Institute of Chartered Financial Analysts of India (ICFAI) University –Thanh, d. V.; Jorstad, I.; Dustdar, S.: Mobile Multimedia Collaborative Services. (2006) Additional reading –Jia Zhang, Jen-Yao Chung: A SOAP-Oriented Component-Based Framework Supporting Device-Independent Multimedia Web Services. ISMSE 2002: 40-47

12 Course materials Discovery and delivery –Yi Cui, Klara Nahrstedt, Dongyan Xu: Seamless User-Level Handoff in Ubiquitous Multimedia Service Delivery. Multimedia Tools Appl. 22(2): (2004) –Conor Muldoon, Gregory M. P. O'Hare, Rem W. Collier, Donnacha Phelan, Robin Strahan: Intelligent Delivery of Multimedia Content in a Device Aware Ubiquitous Environment. Multimedia Information Systems 2005: –Ricky Robinson, Jadwiga Indulska: A Context-Sensitive Service Discovery Protocol for Mobile Computing Environments. ICMB 2005: –Zhou Wang and Hend Koubaa: Discovering Multimedia Services and Contents in Mobile Environments. Handbook of Research on Mobile Multimedia

13 Course materials Deploy and Management –Chih-Cheng Lo, Wen-Shyen E. Chen: Deploy Multimedia-on- Demand Services over ADSL Networks. IEEE Pacific Rim Conference on Multimedia 2002: –Klara Nahrstedt, Wolf-Tilo Balke: A taxonomy for multimedia service composition. ACM Multimedia 2004: 88-95

14 Course materials Other issues –Stefan Tai, Thomas A. Mikalsen, Eric Wohlstadter, Nirmit Desai, Isabelle Rouvellou: Transaction policies for service- oriented computing. Data Knowl. Eng. 51(1): (2004) –Minsoo Lee, Gwanyeon Kim, Sehyun Park, Sungik Jun, Jaehoon Nah, Ohyoung Song: Efficient 3G/WLAN Interworking Techniques for Seamless Roaming Services with Location-Aware Authentication. NETWORKING 2005: –Zhiwen Yu and Daqing Zhang: Middleware Support for Context-Aware Ubiquitous Multimedia Services. Handbook of Research on Mobile Multimedia.

15 Multimedia Services over Networks Service provider Service client Service registry Publish Find/discovery Bind Multimedia system Review/background Framework/ Architecture Deployment/ Management Delivery Issues: Transactions/mobility/locations

16 Distributed Multimedia Systems Chapter 15 – CDK book Slides

17 A distributed multimedia system Figure 15.1 Applications: –non-interactive: net radio and TV, video-on-demand, e-learning,... –interactive: voice &video conference, interactive TV, tele-medicine, multi-user games, live music,...

18 Learning objectives To understand the nature of multimedia data and the scheduling and resource issues associated with it. To become familiar with the components and design of distributed multimedia applications. To understand the nature of quality of service and the system support that it requires. To explore the design of a state-of-the-art, scalable video file service; illustrating a radically novel design approach for quality of service.

19 Multimedia in a mobile environment Applications: –Emergency response systems, mobile commerce, phone service, entertainment, games,...

20 Characteristics of multimedia applications Large quantities of continuous data Timely and smooth delivery is critical –deadlines –throughput and response time guarantees Interactive MM applications require low round-trip delays Need to co-exist with other applications –must not hog resources Reconfiguration is a common occurrence –varying resource requirements Resources required: –Processor cycles in workstations –and servers –Network bandwidth (+ latency) –Dedicated memory –Disk bandwidth (for stored media) At the right time and in the right quantities

21 Application requirements Network phone and audio conferencing –relatively low bandwidth (~ 64 Kbits/sec), but delay times must be short ( < 250 ms round-trip) Video on demand services –High bandwidth (~ 10 Mbits/s), critical deadlines, latency not critical Simple video conference –Many high-bandwidth streams to each node (~1.5 Mbits/s each), high bandwidth, low latency ( < 100 ms round-trip), synchronised states. Music rehearsal and performance facility –high bandwidth (~1.4 Mbits/s), very low latency (< 100 ms round trip), highly synchronised media (sound and video < 50 ms).

22 System support issues and requirements Scheduling and resource allocation in most current OS’s divides the resources equally amongst all comers (processes) –no limit on load –  can’t guarantee throughput or response time MM and other time-critical applications require resource allocation and scheduling to meet deadlines –Quality of Service (QoS) management Admission control:controls demand QoS negotiation:enables applications to negotiate admission and reconfigurations Resource management: guarantees availability of resources for admitted applications –real-time processor and other resource scheduling

23 Characteristics of typical multimedia streams Data rate (approximate) Sample or frame frequency size Telephone speech64 kbps8 bits8000/sec CD-quality sound1.4 Mbps16 bits44,000/sec Standard TV video (uncompressed) 120 Mbpsup to 640x 480 pixelsx 16 bits 24/sec Standard TV video (MPEG-1 compressed) 1.5 Mbpsvariable24/sec HDTV video (uncompressed) 1000–3000 Mbpsup to 1920x 1080 pixelsx 24 bits 24–60/sec HDTV video MPEG-2 compressed) 10–30 Mbpsvariable24–60/sec Figure 15.3

24 Typical infrastructure components for multimedia applications : multimedia stream White boxes represent media processing components, many of which are implemented in software, including: codec: coding/decoding filter mixer: sound-mixing component Figures 15.4 & 15.5 ComponentBandwidthLatencyLoss rateResources required Camera Out:10 frames/sec, raw video 640x480x16 bits Zero ACodecIn: Out: 10 frames/sec, raw video MPEG-1 stream InteractiveLow10 ms CPU each 100 ms; 10 Mbytes RAM BMixerIn: Out: 2 44 kbps audio 1 44 kbps audio InteractiveVery low1 ms CPU each 100 ms; 1 Mbytes RAM HWindow system In: Out: various 50 frame/sec framebuffer InteractiveLow5 ms CPU each 100 ms; 5 Mbytes RAM KNetwork connection In/Out:MPEG-1 stream, approx. 1.5 Mbps InteractiveLow1.5 Mbps, low-loss stream protocol LNetwork connection In/Out:Audio 44 kbpsInteractiveVery low44 kbps, very low-loss stream protocol This application involves multiple concurrent processes in the PCs Other applications may also be running concurrently on the same computers They all share processing and network resources

25 The QoS manager’s task Figure 15.6

26 QoS Parameters Bandwidth –rate of flow of multimedia data Latency –time required for the end-to-end transmission of a single data element Jitter variation in latency :– dL/dt Loss rate –the proportion of data elements that can be dropped or delivered late

27 Admission control Admission control delivers a contract to the application guaranteeing: For each computer: cpu time, available at specific intervals memory Before admission, it must assess resource requirements and reserve them for the application –Flow specs provide some information for admission control, but not all - assessment procedures are needed –there is an optimisation problem: clients don't use all of the resources that they requested flow specs may permit a range of qualities –Admission controller must negotiate with applications to produce an acceptable result For each network connection:  bandwidth  latency For disks, etc.:  bandwifth  latency

28 Resource management Scheduling of resources to meet the existing guarantees: Fair scheduling allows all processes some portion of the resources based on fairness: E.g. round-robin scheduling (equal turns), fair queuing (keep queue lengths equal) not appropriate for real-time MM because there are deadlines for the delivery of data Real-time scheduling traditionally used in special OS for system control applications - e.g. avionics. RT schedulers must ensure that tasks are completed by a scheduled time. Real-time MM requires real-time scheduling with very frequent deadlines. Suitable types of scheduling are: Earliest deadline first (EDF) Rate-monotonic e.g. for each computer:  cpu time, available at specific intervals  memory

29 Scaling and filtering Source Targets High bandwidth Medium bandwidth Low bandwidth Figure 15.9 Scaling reduces flow rate at source –temporal: skip frames or audio samples –spatial: reduce frame size or audio sample quality Filtering reduces flow at intermediate points –RSVP is a QoS negotiation protocol that negotiates the rate at each intermediate node, working from targets to the source.

30 Video on demand for a large number of users Quality of service Scalable and distributed Low cost hardware Fault tolerant Tiger design goals (self-study) Tiger Network Clients

31 Supports the delivery of over 100 million videos per day –That is per hour, per minut, per second The team: 2 sysadmins, 2 scalability software architects 2 feature developers, 2 network engineers, 1 DBA. What's essential to your service and prioritize your resources and efforts around those priorities Keep it simple! Simplicity allows you to re-architect more quickly so you can respond to problems Youtube

32 What is a Multimedia System? A system that involves: –Generation: production/authoring tools –Representation: compression and formats –Storage: file system design –Transmission: networking issues, QoS –Search and retrieval: database management –Delivery: service design, QoS of multimedia information

33 Service-oriented Architecture What is a service? –A Windows Service? RPC Locator, EventLog, DHCP Client, –Software Service? Distribution Service, Alert Service Security Service, Log Service –Business Service? Common Operational Picture, Navigation Accounts Receivable, Customers A service is a unit of work done by a service provider to achieve desired end results for a service consumer.

34 Papers Mike P. Papazoglou: Service-Oriented Computing: Concepts, Characteristics and Directions. WISE 2003: 3-12 –Michael N. Huhns, Munindar P. Singh: Service-Oriented Computing: Key Concepts and Principles. IEEE Internet Computing 9(1): (2005) Jilles van Gurp, Anssi Karhinen, Jan Bosch: Mobile Service Oriented Architectures (MOSOA) Additional reading –Donald F. Ferguson, Marcia L. Stockton: Service-oriented architecture: Programming model and product architecture. IBM Systems Journal 44(4): (2005) –Mark Little: Transactions and Web services. Commun. ACM 10(43) (2003) –Gerald C. Gannod and Janet E. Burge and Susan D. Urban: Issues in the Design of Flexible and Dynamic Service-Oriented Systems. SDSOA '07: Proceedings of the International Workshop on Systems Development in SOA Environments

35 Services… Technology neutral –Invocation mechanisms (protocols, descriptions, discovery) should comply with accepted standard Loosely coupled –Must not require knowledge at the service side Support location transparency –Service can be discovered and invoked by clients irrespective of their locations Simple and composite services

36 Loosely coupling Outlet plug adapters Standard???

37 SOA vs. Objects/components Services represent complete business functions Re-used CD-player example –CD –Players –Object oriented CD+Player Other issues –Stateless service more scalable & reliable –Stateful service more efficiency –Itempotent request

38 Service-oriented Architecture SOA is an architecture style whose goal is to achieve loose coupling among interacting software agents –Consumers and Providers are agents Minimum difference of plug adaptors We need –A small & simple interface to all participating agents –Descriptive messages constrained

39 How can we identify an SOA? Descriptive message –Order service, not how to “cook” the service Understandable protocols/messages –Look at the menu, do not describe the “food” Extensibility –vs. restrictions Discovery service

40 An overview picture Example –Develop a movie information service Requirements

41 Services oriented architecture - basic Service provider Service client Service registry Publish Find/discovery Bind

42 Service interfaces and implementation

43 Extened SOA Basic SOA does not address –Management –Service orchestration –Transaction, security, … Extended SOA

44 Extened SOA

45 Web services Service provider Service client Service registry Publish Find/discovery Bind Internet protocols: HTTP, FTP XML messages WSDL UDDI SOAP vs. SOA definition?

46 Web services