1

TTM5Networked Services and Multimedia Systems,

advanced

Professor Peter Herrmann/Postdoc Hien Nam Le

Dept. Telematics (ITEM)University of Science and Technology (NTNU)

hiennam@item.ntnu.noRm A277

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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

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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.

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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

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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

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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

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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

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An overview picture

• Example

– Develop a movie information service

• Requirements

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Services oriented architecture - basic

Service provider

Service client

Service registry

Publish

Find/discovery

Bind

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Service interfaces and implementation

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Extened SOA

• Basic SOA does not address– Management

– Service orchestration

– Transaction, security, …

• Extended SOA

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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?

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Web services