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1
TTM5Networked Services and Multimedia Systems,
advanced
Professor Peter Herrmann/Postdoc Hien Nam Le
Dept. Telematics (ITEM)University of Science and Technology (NTNU)
[email protected] 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
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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– Email or walk-in rm A277
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Schedule
• 7 two-hours seminars
Week Date Topics40 03.10.07 Introduction & review
41 10.10.07
42 17.10.07
43 24.10.07
44 31.10.07 Guest lecture: Open Mobile ServicesLecturer: Prof. Do, van Thanh
45 07.11.07
46 14.11.07
47 21.11.07
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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
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An overview picture
• Example
– Develop a movie information service
• Requirements
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An overview picture
Live Free or Die Hard
John McClane takes on anInternet-based terroristorganization who is …
Text Photos Video clip
Multimedia System• Storage• Presentation• Search and retrieval
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An overview picture
Multimedia System/Application
Tools, framework, architecture
Development
Clients
Interactions
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An overview picture
Multimedia Services
ServiceClients
Services
Multimedia System/Application
Clients
Interactions
Service-oriented Computing/Service-oriented Architecture
Service provider
Service clients
Service registry
Publishing
Finding
Binding
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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): 75-81 (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): 753-780 (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
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Course materials
• Framework and architecture– Jia Zhang, Jen-Yao Chung: An open framework supporting multimedia
web services. Multimedia Tools Appl. 30(2): 149-164 (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): 203-220 (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
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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): 137-170 (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: 131-145
– Ricky Robinson, Jadwiga Indulska: A Context-Sensitive Service Discovery Protocol for Mobile Computing Environments. ICMB 2005: 565-572
– Zhou Wang and Hend Koubaa: Discovering Multimedia Services and Contents in Mobile Environments. Handbook of Research on Mobile Multimedia
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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: 295-302
– Klara Nahrstedt, Wolf-Tilo Balke: A taxonomy for multimedia service composition. ACM Multimedia 2004: 88-95
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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): 59-79 (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: 370-381
– Zhiwen Yu and Daqing Zhang: Middleware Support for Context-Aware Ubiquitous Multimedia Services. Handbook of Research on Mobile Multimedia.
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Multimedia Services over Networks
Service provider
Service client
Service registry
Publish
Find/discovery
Bind
Multimediasystem
Review/background
Framework/Architecture
Deployment/Management
Delivery
Issues: Transactions/mobility/locations
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Distributed Multimedia Systems
Chapter 15 – CDK bookSlides
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A distributed multimedia system
Wide area gatewayVideoserver
DigitalTV/radioserver
Video cameraand mike
Local network Local network
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, ...
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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.
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Multimedia in a mobile environment
• Applications:
– Emergency response systems, mobile commerce, phone service, entertainment, games, ...
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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 timeand in the right quantities
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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).
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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 andreconfigurations
• Resource management: guarantees availability of resources for admitted applications
– real-time processor and other resource scheduling
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Characteristics of typical multimedia streams
Data rate(approximate)
Sample or frame frequency size
Telephone speech 64 kbps 8 bits 8000/secCD-quality sound 1.4 Mbps 16 bits 44,000/secStandard TV video(uncompressed)
120 Mbps up to 640 x 480pixels x 16 bits
24/sec
Standard TV video (MPEG-1 compressed)
1.5 Mbps variable 24/sec
HDTV video(uncompressed)
1000–3000 Mbps up to 1920 x 1080pixels x 24 bits
24–60/sec
HDTV videoMPEG-2 compressed)
10–30 Mbps variable 24–60/sec
Figure 15.3
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Typical infrastructure components for multimedia applications
Microphones
Camera
Screen
Window system
CodecD
BMixer
PC/workstation PC/workstation
C Videostore
Networkconnections
K
L
M
CodecA G
CodecH
Windowsystem
Video file system
: multimedia stream
White boxes represent media processing components, many of which are implemented in software, including:
codec: coding/decoding filtermixer: sound-mixing component
Figures 15.4 & 15.5
Component Bandwidth Latency Loss rate Resources required
Camera Out: 10 frames/sec, raw video640x480x16 bits
Zero
A Codec In:Out:
10 frames/sec, raw videoMPEG-1 stream
Interactive Low 10 ms CPU each 100 ms;10 Mbytes RAM
B Mixer In:Out:
2 44 kbps audio1 44 kbps audio
Interactive Very low 1 ms CPU each 100 ms;1 Mbytes RAM
H Windowsystem
In:Out:
various50 frame/sec framebuffer
Interactive Low 5 ms CPU each 100 ms; 5 Mbytes RAM
K Networkconnection
In/Out: MPEG-1 stream, approx.1.5 Mbps
Interactive Low 1.5 Mbps, low-lossstream protocol
L Networkconnection
In/Out: Audio 44 kbps Interactive Very low 44 kbps, very low-lossstream 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
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The QoS manager’s task
Application components specify their QoS requirements to QoS manager
Yes No
Yes No
Flow spec.
Resource contract
Admission control QoS negotiation
QoS manager evaluates new requirementsagainst the available resources.
Sufficient?
Reserve the requested resources
Allow application to proceed
Application runs with resources as per resource contract
Negotiate reduced resource provision with application.Agreement?
Do not allow application to proceed
Application notifies QoS manager of increased resource requirements
Figure 15.6
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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
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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:bandwidthlatency
For disks, etc.:bandwifthlatency
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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 intervalsmemory
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Scaling and filtering
SourceTargets
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.
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• 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
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• Supports the delivery of over 100 million videos per day– That is 4.167.000 per hour, 69.000 per minut, 1.150
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• http://highscalability.com/youtube-architecture
Youtube www.youtube.com
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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): 75-81 (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): 753-780 (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
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Loosely coupling
• Outlet plug adapters
• Standard???
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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
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Web services
Service provider
Service client
Service registry
Publish
Find/discovery
Bind
Internet protocols: HTTP, FTPXML messages
WSDL
UDDI SOAP
vs. SOA definition?
46
Web services