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Multimedia ApplicationsInstructor: Hamid R. Rabiee
Spring 2013
Outline
1. Digital TV Introduction to MHP
DVB
MHP
2. Voice Over IP Introduction to VOIP
Challenges of VOIP
IP telephony
3. IPTV Introduction to IPTV
Key features
IPTV components
4. Multimedia Conferencing Introduction to Multimedia Conferencing
Multimedia Conferencing Components
Types of Multimedia Conferencing
Communication in various network
topologies
Digital Media Lab - Sharif University of Technology2
Digital TV
Why digital TV?
Better image quality
More channels
Multiple audio channels
Subtitles
The whole new world of services
Digital Media Lab - Sharif University of Technology4
Digital TV Standards
Digital Video Broadcasting (DVB)
Satellite transmission standard (DVB-S)
Cable standard (DVB-C)
Terrestrial broadcast services standard (DVB-T)
Multimedia Home Platform standard (MHP)
Advanced Television Systems Committee (ATSC)
Terrestrial digital broadcasting standard (ATSC-T)
Cable distribution standard (ATSC-C)
Integrated Services Digital Broadcasting (ISDB)
Satellite broadcasting standard (ISDB-S)
Cable standard (ISDB-C) for cable TV networks
Terrestrial digital broadcasting standard (ISDB-T)
Terrestrial Sound Broadcasting (ISDB-TSB) for terrestrial broadcasting
Digital Media Lab - Sharif University of Technology5
Appendix A
Voice Over IP (VOIP)
Introduction to VOIP
What is VOIP? VoIP is the ability to make telephone calls and send faxes over IP-based data networks with a suitable quality
of service and superior cost/benefit. VOIP Components
Servers : For processing IP calls and manage interaction with PBX etc. End-point devices such as phones Media and VoIP gateways IP network
Why VOIP? Demand for Multimedia communication Demand for integration of Voice and Data networks Cost Reduction in long distance telephone calls
How VoIP works Continuously sample audio Convert each sample to digital form Send digitized stream across Internet in packets Convert the stream back to analog for playback
Challenge Voice transmission delay Call setup: call establishment, call termination, etc. Backward compatibility with existing PSTN (Public Switched Telephone Network)
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Origins of VOIP
Internet Telephony software for multimedia PCs (1995)
Users frustrated by poor QoS, difficulty of use, lack of interoperability
Standards are critical for success
Coding/decoding (codec) between analog voice and digital packets
Locating the party you want to call
Signaling to set up, modify, tear down the voice call
Access to vertical services (call forwarding, 3-way calling, …)
Gateways to PSTN
Media routing, quality of service (QoS) left to other IP mechanisms (not
VoIP-specific)
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VOIP: Goals and Benefits
Consolidation of voice, data on a single network
Simplify infrastructure, operations; provide bundled services
Support for intelligent terminals as well as phones
Increased flexibility
Multiple bit rates, multiple media types, richer signaling
Distinguish calls from connections (add/modify streams during call)
Separation of service control from switching/routing
Accelerate new service development, increase end-user control, evolve from
VoIP towards advanced services
Expansion of competition
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Voice To/From IP
Analog
Digital
Voice
CODEC: Analog to Digital
Compress
Create Voice Datagram
Add Header(RTP, UDP, IP, etc)
N etw ork
Digital
Analog
Process Header
Re-sequence and Buffer Delay
Decompress
CODEC: Digital to Analog
N etw ork
Voice
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NGN Architecture (Next-Generation Network)
Oriented towards application of VoIP (or VoATM) to large-scale public
networks
Focus on scalability, network control, support for traditional phones,
sophisticated gateway (GW) to the PSTN and its services
Media GW interfaces voice stream to PSTN trunk or phone line
Signaling GW allows signaling directly to SS7 network
Softswitch controls Media GWs and does call processing
Allows smaller, cheaper Media GWs (e.g., for individual homes)
Control via MGCP (Media Gateway Control Protocol) or H.248
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Core Packet Core Packet NetworkNetwork
Softswitch
CustomerGateway
DSL or PacketCable
Access
NGNNGN ExampleVoice over DSL or Cable Modem
H323/SIPIP Phones,
PCs
SCP
Class 5 Switch
SS7 Signaling Network
PSTN
MGCPSS7
Gateway
Trunk GatewayVoice Streams
MG
CP
ISUP, TCAP
Can also use to interconnect PSTN clouds (long-distance), or PSTN switches (interoffice backbone)
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Challenges of VOIP
Latency Latency is the time taken for a packet to arrive at its destination
Packet switching overhead Congestion
Latency may result in voice synchronization problems Jitter
Jitter is the delay experienced in receiving a packet when a packet is expected to arrive at the end point at a certain time
Bandwidth When bandwidth is shared between voice and computer data, certain bandwidth may have
to be allocated for voice communication on a network Packet loss
Packet loss in unavoidable It can be minimally tolerated in voice transmission
It should not, in the first place, distort the audio Reliability
Because the computer network is used, the reliability of the network will have an impact on the telephony service
In the analog telephone industry, reliability of 99.999 percent uptime is required The above is known as five nines
VoIP networks can achieve over 98 percent reliability ?
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Challenges of VOIP (cont.)
Scalability Ability to add more telephony equipment as the company grows
Network bandwidth and other issues may have an effect on scalability Security
As VoIP uses the Internet, for example, it is vulnerable to the same type as security risks Hacking Denial of service Eavesdropping
Features IP telephony need to match and, in the long run, exceed the features provided by the
PSTN Call waiting Three way calling etc.
Interoperability IP telephony equipment manufactured by different vendors must be able to talk to
each other Standardized protocols are needed
Switch over cost The cost of migrating from legacy PBX to IP PBX
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More in Appendix B
IP Telephony in Appendix C
Enterprise VoIP
IP PBX
Centrexor PBX
Softswitch
GWGW
Location A
Location B
GWGW
Many possible combinations of VoIP and circuit-switched telephony
IP phoneIP
phone
PSTN
NetworkCore IP
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IPTV
Internet Protocol Television (IPTV)
IPTV (Internet Protocol television): the delivery of programming by video stream encoded as a series of IP packets.
IPTV can be free or fee-based and can deliver either live TV or stored video to the Television one addressed program at a time
Traditional Pay-Television: all programming is broadcast simultaneously and is available by tuning to the channel.
IPTV and Internet TV IPTV delivered to TV set, not PC IPTV is provided by a few large telecom providers Internet TV: anyone can create an endpoint and publish that on a global basis.
(YouTube) They are competitors
Introduction to IPTV
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Why IPTV?
IPTV will provide better quality of service than
Internet streaming video
IPTV has the potential to offer an interactive,
customized experience
IPTV is effective whether you require a service to
delivery or not
Entertainment.
Advertising or information.
A hospitality system for hotels or hospitals.
Regular internal bulletins.
Up to date financial updates and market information.
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Key Features of IPTV
Support for interactive TV: Two-way capabilities of IPTV systems allow
service providers to deliver interactive TV applications
Time shifting: IPTV in combination with a digital video recorder allows the
time shifting of programming content
Personalization: Allow end-users to personalize their TV viewing habits (what
& when they want to watch )
Low bandwidth requirements: Allow service providers to only stream the
requested (not every) channel to the user => netwrok operators can conserve
bandwidth on their network
Accessible on multiple devices: users can use their PCs and mobile devices as
well as television to access IPTV services
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How Is IPTV Done?
Firstly we have to convert the incoming signals;
Terestrial TV,
Satellite TV,
FM and DAB Radio
into an IP format, MPEG2 and MPEG4.
To do this we us an IPTV Encoder.
The converted signals are then transmitted over the
LAN network with all the other data traffic, using
Multicast protocols.
Example shows, CCTV, VoD, Satellite and
Terrestrial TV being transmitted over the same
network.
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Why Are Organizations Adopting IPTV?
Television and video services can easily be supplied to all computers on a
network, increasing staff access to news and company information.
The same infrastructure can be used no matter how many channels or viewing
devices are attached to the network. No special wiring or video distribution
design is required.
Consistently high video quality is maintained regardless of the number of
people watching TV and Video services.
Costs can be reduced by converging IPTV with existing data networks.
Prevent major internal disturbance through the use of existing networks
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Appendix D
Overlay Network Service for IPTV
Overlay Network
IPTV Customer IPTV Video Server
Transport Network
IPTV Application
Overlay Node
IPTV ApplicationIPTV Application
consists of virtual network topologies on top of the physical network
responsible for forwarding and handling of IPTV application data
much more aggregate information and computing resources for clients or peers than from a limited number of centralized servers.
operated in organized and coherent way by the third party service provider or network provider to provide IPTV services.
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Overlay Network Architecture
Network Provider 1 IPTV Server
BandwidthManager
Session Manager
Overlay Network
Network Provider 2
Overlay Node
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Functions in IPTV Overlay Network
Control Function in IPTV Overlay Network
Perform session control and management for IPTV overlay network.
Establish and to maintain the network and system resources.
Virtual link among overlay nodes creates virtual topologies to deliver IPTV information.
Find optimal physical delivery paths for QoS and required network resource.
Multicast Function in IPTV Overlay Network
constructing different multicast trees depending on IPTV application parameters or application
classes.
supports efficient routing and resource usage by overlay multicast control.
In order to provide scalability for multicast function, hierarchical structure for overlay multicast will
be introduced in IPTV overlay networks.
Managing session to keep track of session configuration and maintenance for IPTV
service, and provide session initiation, release and management.
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Control Functions for IPTV Overlay Multicast
IPTV Session Manager (ISM)ISM is involved in session configuration and maintenance
for IPTV service flows.
- Session initialization: ISM allocates ISID (IPTV Session ID) for new session.
- Session release: Session can be released as needed
- Session membership management
- Session status monitoring
IPTV Multicast Agent ( IMA )- Session join: each IMA contacts with Session Manager.
- Session leave: when an IMA wants leave the session
- Session maintenance: relay request and its response will be exchanged between the two IMAs periodically.
- Loop detection & avoidance
- Partitioning detection & recovering
- Parent switching
- IPTV Session status reporting
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Appendix E
Multimedia Conferencing
Introduction
Multimedia Conferencing = an interactive tool that incorporates audio, video, and computing, and communications technologies to allow people in different locations To electronically collaborate face-to-face, in real time To share all types of information including data, documents, sound and picture.
What is needed? Efficient transport:
Enable real time transmission. Avoid sending the same content more than once. Best transport depends on available bandwidth and technology.
Audio processing: How to ensure Audio/Video Quality? How to Mix the streams?
Conference setup: Who is allowed to start a conference? How fast can a conference be initiated?
Security and privacy: How to prevent not-wanted people from joining? How to secure the exchanged content?
Floor control: How to maintain some talking order?
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Steps to Choosing A MultimediaConferencing System1) Intended use for your system: how do you wish to use the equipment and whom are you going to talk to?
2) Number of sites: How many offices do you need to communicate with and what resources will each have at their disposal?
3) Number of participants per site: How many people do you want to participate in video calls at your various
locations? Do you want the same videoconferencing set-up for every location? Or, do you want to have a more deluxe system for your headquarters?
4) Size of your rooms: Where do you want to put the equipment? For example, is your current conference or meeting room big enough to add a system? Does your current meeting environment offer sufficient size, lighting and ancillary resources to accommodate an appropriate videoconferencing solution?
5) Connectivity: ISDN, BRI, PRI, T-1, Fractional T, ATM, Frame Relay, xDSL, Cable-modem? What connectivity best suits your internal communication requirements? Will the connection be dedicated to the conferencing system? What types of communications do you plan? Voice,video,data? (The type of communication will determine bandwidth requirements.) Also, what connectivity will remote sites make use of?
6) What type of systems or formats will you be calling: An ISDN system typically sends and receives voice and video data using the h.320 standard. An IP based (network) system typically communicates using the h.323 voice/video standard. You can only call between systems that subscribe to the same standard. However, gateway and bridge devices are available that will allow you to translate calls between the common standards. (Standards are defined by the International Telecommunications Union and are the same worldwide.)
7) Do you need data capability in addition to video & audio: Are you just looking to only see and talk to the other
people, or are you going to require the ability to do collaborative computing and share data? Do you want to share computer files and documents on screen? Will you need to show PowerPoint presentations?
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Appendix F
How to videoconference in a Centralized Topology All register and send messages at a central point Central point forwards to others Tightly coupled: Some instances know all information about all participants at
all times
Advantages Simple to implement Single point of failure Appropriate for small to medium sized conferences Simple to manage and administer:
Allows access control and secure communication Allows usage monitoring Support floor control
Most widely used scenario No need to change end systems
Disadvantages High bandwidth consumption at center point
Must receive N flows High processing overhead at center point
Must decode N flows mix the flows and encode N flows With no mixing the central point would send Nx(N-1) flows
’06 | 29
All establish a connection to each other All can send directly to the others Each host will need to maintain N connections
Outgoing bandwidth: Send N copies of each packet simple voice session with 64kb/s would translate to 64xN
kb/s
Incoming bandwidth: If silence suppression is used then only active speakers send
data
Disadvantage In case of video lots of bandwidth might be consumed
Unless only active speakers send video End systems need to mix the traffic –more complex end systems
Advantage Security: simple! do not send data to members you do not trust
How to videoconference in a Full MeshTopology
’06 | 30
All establish a connection to the chosen mixer.
Outgoing bandwidth at the mixer end point: Send N copies of each packet simple voice session with 64kb/s would translate to 64xN
kb/s
Incoming bandwidth: If silence suppression is used then only active speakers send
data
Advantage Mostly used solution for three-way conferencing.
Disadvantage In case of video lots of bandwidth might be consumed
Unless only active speakers send video One of the end systems need to mix the traffic –more
complex end system.
How to videoconference in an End-Point-BasedTopology
’06 | 31
Benefits of Videoconferencing
Reduces Travel Expenses: There are numerous situations where you can save a lot of money on airfare and hotel costs, not to mention saving the loss in productivity from being out of the office.
Allows Multi-point Meetings Across Time Zones & International Boundaries: Videoconferencing lets you put together a meeting of various people, from different locations, for a common discussion.
Improves Effectiveness: Visually seeing the part during a videoconference is far more effective and meaningful than trying to describe it over the phone.
Increases Productivity: Websites and the Internet let us quicken the speed of communication. The use of videoconferencing will be the next driver for productivity because you will be able to keep in closer contact with customers. This closeness will lead to new ideas on how to speed up the development of new products and services.
Improves Communication & Reinforce Relationships: During a videoconference you can see
the facial expressions and body language of conference participants which are both important aspects of communication that are lost with a basic telephone call. Videoconferencing also allows the opportunity for more of your staff to have contact with your customers.
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Appendix A
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Digital TV Standards (cont.)
Table 1 – Comparison of Digital TV standards
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DVB (Digital Video Broadcasting)
DVB (Digital Video Broadcasting) is a set of international open standards for digital television
DVB standards are maintained by the DVB Project (international industry consortium) and published by a Joint Technical Committee (JTC) of European Telecommunications Standards Institute (ETSI), European Committee for Electrotechnical Standardization (CENELEC) and European Broadcasting Union (EBU)
DVB standards are publicly available, free of charge at http://www.etsi.org and http://www.dvb.org
DVB standards are used in Europe; similar standards are ATSC (used in USA/North America), ISDB (used in Japan/South America) and DMB (used in China, Korea)
Digital Media Lab - Sharif University of Technology35
DVB (Digital Video Broadcasting) (cont.)
DVB standards define the physical layer and data link layer of the distribution system
DVB standards are based on MPEG-2 and MPEG-4 standards and all data is
transmitted in MPEG Transport Streams
Most important DVB standards are:
for satellite TV: DVB-S, DVB-S2
for terrestrial (aerial) TV: DVB-T, DVB-T2
for cable TV: DVB-C, DVB-C2
for handheld devices TV: DVB-H, DVB-SH
DVB has a conditional access system (DVB-CA) through Common Scrambling
Algorithm (DVB-CSA) and a physical Common Interface (DVB-CI)
DVB-S and DVB-C were ratified in 1994 and DVB-T in 1997
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DVB-J
Special Java platform for digital television
JVM is part of OS A few interfaces
DAVIC Digital Audio Visual Council Payment interfaces Infrastructure interfaces Tuning interfaces
DVB Digital Video Broadcasting Extensions and limitations to Java-
interfaces Data access interfaces I/O-device interfaces Security interfaces
Java Basic interfaces: lang, util, beans... Graphical libraries: AWT, JMF Service interfaces: JavaTV
HAVi Home Audio Video Interoperability Display and user interface libraries
Digital Media Lab - Sharif University of Technology37
DVB-HTML
Digital Video Broadcasting – HyperText Markup Language HTML-like environment for television Technologies
xml, xhtml, css, dom, ECMAScript Pages or ”screens” are received from media carusel
Same way of thinking as in normal teletext service. Modern version of Teletext services
DVB-HTML services are very often called as supertext-tv services. It will replace the normal teletext services. New services possible but already launched applications are the same as in normal teletext but with
pictures Interactive services
DVB-HTML includes forms and links as a way to browse within service Forms makes it possible to build up somehow interactive content.
Need to remember that actual content for pages is received from media carusel. Few example services
News Extra information about tv-series or events Traffic jam information, bus timetables Subject specific portals Payment services
Order new services or products via television. (requires feedback channel)
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Example of DVB-HTML page
<?xml version="1.0" encoding="ISO-8859-1"?><!DOCTYPE html SYSTEM "supertext.dtd"> <html> <head> <title>SM-Liiga</title> <link rel="stylesheet" href="styles1Column.css"/> </head> <body> <div class="title"> <span style="width: 200;">Tilastot
</span>
</div> <div class="main"> <br><span class="lihavointi"></span><br><br> <table> <tr> <td>SARJATAULUKKO</td> <td ></td> </tr> <tr> <td bgcolor="#cccccc"></td> </tr> ........
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Multimedia Home Platform (MHP)
MHP is An open DVB standard which defines a whole set of technologies to implement
A set of Java APIs
A set of HTML document type definitions
A set of compatibility tests
Digital interactive multimedia services in the home
Includes home terminal (e.g., set-top box, TV set, or PC) and its peripherals and the in-home digital
network
Covers three application areas (i.e., enhanced broadcasting, interactive broadcasting, and Internet
access)
MHP goals
primary goal of the MHP is to enable the birth of horizontal markets for digital television and
multimedia services where there is open competition between content providers, network operators or
platform manufacturers at each level in the delivery chain.
Another goal is to exploit the potential for convergence between broadcasting, the Internet and
consumer electronics.
Digital Media Lab - Sharif University of Technology40
Multimedia Home Platform (MHP) (cont.)
Three main standards are related to MHP
MHP 1.0.x (1.0.0 – 1.0.3) The original MHP specification plus updates The most commonly deployed version of MHP
MHP 1.1.x Adds elements that were not finished in time for MHP 1.0.0 HTML support, stored applications, Internet client APIs, smart card APIs Still a work in progress Version 1.1.2 coming in April 2005
Globally Executable MHP (GEM) A subset of MHP 1.0.2 Designed to form the basis of other DTV middleware standards Currently used by OCAP, ACAP and ARIB B23
Also PVR for MHP specification (to be published April 2005) Adds support for PVR functionality to MHP receivers Compatible with OCAP PVR extensions
Digital Media Lab - Sharif University of Technology41
MHP profiles
+Java VM+DVB Java APIs+Basic media formats
(MPEG, GIF, JPEG, PNG, etc.)
+Broadcast transport protocols
+ Java APIs for return channel+ Protocols for return channel
HTTP 1.0, DNS, HTTPS mandatoryHTTP 1.1, DSMCC-UU optional
+ Java Internet client APIs+ Web browser & email client+ DVB-HTML (optional)
+ DVB-HTML (optional)+ App download over HTTP + Inner applications
+ Application storage+ Smart card APIs
Interactive Broadcast
profile
Enhanced Broadcast
profile
Internet Accessprofile
MHP 1.0.x MHP 1.1.x
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Multimedia Home Platform (MHP) (cont.)
MHP architectural layers
Resources: MPEG processing, I/O devices, CPU, memory and a graphics system
System software: The system software uses the available resources in order to provide an abstract view of
the platform to the applications.
Applications : They are controlled by the application manager
API Interface: Defined by MHP as abstraction layer between different provider's applications and the
specific hardware and software on the terminal
Digital TV applications use APIs to access the actual resources of the receiver, including: databases,
streamed media decoders, static content decoders and communications.
Figure 1 – Basic MHP Architecture
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MHP Applications
Information services super teletext, etc.
Show-related interactivity online quiz show, online
voting, etc.
Games
T-commerce and banking
Internet access
super teletext
Game
Banking
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Remote controller, An MHP Device
MHP defines Arrow keys OK TXT Numbers 0-9 Color keys (in this order): red, green, yellow, blue
There are also other keys, that are not required
NorDig II suggests
Power ON / OFF
Programme UP / DOWN
Volume UP / DOWN
TV
Back
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MHP Graphics
32-bit colors MHP minimum palette (140+48 colors)
Alpha channel 0%, 30%, 100% required by MHP If other values not supported, values are
rounded to these.
3 layers background video graphics
Java drawing primitives
Image formats
JPEG, GIF, PNG, MPEG I-Frame
Scaled video
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MHP Layers
Background
Only one still image
MPEG I-Frame bitmap
Always full-screen
Opacity cannot be set
Video
MPEG-video from TV-stream
Video is scalable
Full screen, 1/4, 1/16
Other if device supports
Some devices supports multiple simultaneous video
streams, but this is not required by MHP-standard
Graphics
Graphic layer
Application graphics
Background
Video
Graphics
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Appendix B
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Challenges of VOIP (cont.)
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Current VOIP Implementations
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Enterprise Applications of VoIP
Leverage spare data-network capacity, minimize phone bills,
create platform for multimedia conferencing
H.323 and SIP both being deployed, softswitches and IP-PBX
options emerging, unclear which will prevail
Examples: Telcordia/SAIC (H.323), Telia (SIP)
Carrier-managed VPN networks last year from AT&T (H.323)
and Worldcom (SIP)
VoIP adoption slower than expected, partly due to plunging PSTN
long-distance prices, QoS concerns
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VOIP Advanced Services
VoIP: natural platform for evolution to advanced services
Supports intelligent terminals and rich signaling
Separates calls from connections
Multimedia capabilities already in the protocols (SIP/H.323)
Removes bottleneck by separating call control from switching
Thus far, focus is almost entirely on voice
For many players (but not all), voice is the killer app
Solve the simpler problem first
This simplifies many network control issues, because of predictability of voice
bandwidth, traffic patterns
But current solutions are likely to require significant extensions to
accommodate more flexible advanced services
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What’s Different About Advanced Services?
Flexibility in media streams, participants, “ownership”; service not pre-defined at
call setup
Multiple media per call, differing (and very wide range of) bandwidths
Dynamic re-configurability during call
Potential for multicast conferencing, streaming
Implications
Call admission control becomes more complex
Much less aggregation, localization of flows than with NGN voice
Usage, traffic patterns may be highly variable and hard to predict
New approaches to traffic engineering, resource allocation and network control will
be needed to address even a modest penetration of these new services
Digital Media Lab - Sharif University of Technology53
Appendix C
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IP Telephony
Internet telephony uses the Internet protocol to send audio, video an data between two or
more users in the real time.
IP telephony is the integration and convergence of voice and data networks, services, and
applications.
The main motivation of development of IP Telephony is the cost saving & integrating new
services.
IP Telephony Standards H.323 standard
Session initiation protocol (SIP)
Media gateway to media controller protocol (MGCP) IP Telephony types
PC to PC
Phone-to-phone over IP
PC-to-Phone
Phone-to-PC
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IP Telephony: PC-to-PC
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IP Telephony: Phone-to-Phone Using Gateways
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IP Telephony: Phone-to-Phone Using Adapter Gateways
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IP Telephony: PC-to-Phone
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Appendix D
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Components of an IPTV System A National head-end - Origination point of network Broadcasts for transmission over the IP
network. Core networks - Usually an IP/MPLS network transporting traffic to the access network Access networks - Distributes the IPTV streams to the Digital Subscriber Line Access
Multiplexer (DSLAMs) Regional head-end – Origination point for local content Customer premises - Where the IPTV stream is terminated and viewed using a Set Top Box
or Computer.
Figure 2 – A typical IPTV system
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Components of an IPTV System (cont.)
Hardware Blocks
BF5333 processor: Design for computational demands, power constraints of
embedded audio and video applications
Figure 3 - An IPTV system block diagram
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Components of an IPTV System (cont.)
Video Encoder ADV7171: converts digital CCIR-601 4:2:2 8- or 16-bit component video
data to an analogue baseband television signal compatible with worldwide standards
Audio Codec AD1836: A codec providing three stereo DACs and two stereo ADCs
Ethernet Interface SMSC LAN91C111 Chip: facilitate the implementation of a third
generation of Fast Ethernet connectivity solutions for embedded applications
Set-Top Box (STB): A dedicated computing device that serves as an interface
between a TV set and a broadband network
Main job = receive incoming IPTV signal & convert to a video signal that can be displayed in
TV
Allow viewers to select their video programming
Supports Web browsing, email & viewing email attachments, advanced multimedia codecs,
instant messaging, and real-time VOIP.
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Components of an IPTV System (cont.)
Software Blocks:
uClinux OS: this OS is loaded to memory and divided into kernel space (contain
system functions) and user space (contain application program)
Video Driver: Responsible for video applications
Audio Driver: Responsible for audio applications
Media Player: uses FFmpeg which is a complete solution to record, convert, &
stream audio and video
Streaming: STB creates connection to server for streaming the media
User Interface: An interface between user & IPTV STB to make STB interactive
with user
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IPTV Issues
Encoding and Compression – The quality of a transmission can be affected from the source depending on the encoding technique and level of compression. Generally speaking increased compression leads to a poorer video quality but a smaller data stream. There is a tradeoff between bandwidth and compression level.
Jitter in IPTV transmission is defined as a short-term variation in the packet arrival time. Jitter is typically caused by network or server congestion. To help combat jitter, STB’s use buffers to smooth out the arrival times of the data packets. I the buffer overflows or underflows, at the STB, there is often a degradation of the video output.
Limited Bandwidth – Bandwidth availability is often an issue that affects the access network or the customers home network. When traffic utilizes the entire bandwidth, packets are dropped, leading to video quality degradation.
Packet Loss - Loss of IP packets may occur for multiple reasons: bandwidth limitations network congestion failed links transmission errors Packet loss usually presents a bursty behavior, commonly related to periods of network
congestion.
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Appendix E
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Additional capabilities of IPTV Overlay Network
Multicast Resource Management
Provide control function to multicast congestion problem
Multicast resource management
Re-negotiation function for additional resource requirements
Multiple data routing function for service/user requirements
Quickly detection of network problems for IPTV services
Provision of Intelligence for IPTV Service Features
Provision of dynamic creation and control function of IPTV Service Communities
QoS+Security+User’s Preference
Keywords/Program searching for IPTV Services
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Overlay IPTV Multicast Control
Group membership management
Group Membership Control
Group Partitioning: Global group partitioning, Server group partitioning
Admission control
support QoS for IPTV services in overlay multicast network
resource control function for IPTV overlay network
Security for IPTV overlay multicast
Confidentiality and Integrity, Authenticity, and Availability.
Classified with some properties for architectures and algorithms for building secure
and scalable information dissemination services on IPTV overlay networks.
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Appendix F
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Multimedia Conferencing Applications
Business Reduce travel costs, improve use of executive time, speed up decision-making, keep
meetings brief and more focused than face-to-face meetings, enable top management to quickly and effectively communicate with employees sitting in multiple locations, provides an effective way of delivering cost-efficient training to individuals without the requirement to consistently travel to central locations.
Distance learning Teachers and students are able to see each other, share documents and discuss topics
together in a situation similar to a traditional classroom setting while they are in various countries.
Saving travel time and expenses, increasing an instructor’s audience, maintaining the ability for interaction between teachers and students
Telemedicine When a person needs medical advice but is unable to visit their personal physician or a
specialist. Videoconferencing enables patients to get the necessary information and expert guidance they need quickly and easily.
Telecommuting/Home office Users can save resources by meeting with clients and/or colleagues via videoconference.
This reduces travel expenses, while maintaining face-to-face contact. For a minimal cost, it is possible to set-up a fully functional videoconferencing system that works in a professional and reliable way from your home office.
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Videoconferencing Codec Unit (End Points) = “BRAIN and HEART” of the Videoconferencing (multimedia conferencing) System It is also known as the Coder-Decoder. Function
1. It takes the video and audio from the camera and microphone 2. Compresses it down3. Transmits it over a network/digital phone line 4. Expands (or Decompresses) the incoming video and audio signal so that it
can be viewed on a display
Camera: The camera types range from a small desktop camera that sits on top of a computer monitor in a desktop system to a high-quality camera that has remote control pan, tilt and zoom (PTZ) features in a room-sized system.
Microphone : small microphones that attach to the Personal Computer in a
desktop conferencing unit, or a microphone designed to work best with a small group of people in a room-sized system.
Components of Multimedia Conferencing
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Components of Multimedia Conferencing(cont.) Video Monitor, XGA Monitor, Plasma Display,
LCD/DLP Projector These display devices are options that can be used to show
the images received from the videoconferencing codec. Videoconferencing systems can use multiple displaying
options. Desktop systems show the video in a small window on the computer monitor. Room-sized systems usually have one or two large video monitors and can display the local audience, as well as the remote audience.
Network Connection This is the connection that carries data between video
systems communicating with one another. The size of the connection and the ability to access it in a consistent manner, determines both video performance and quality of service. The connection can range from an ISDN phone line to a dedicated PRI/T-1 connection or access to a local area network.
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Types of Multimedia Conferencing Systems
Desktop Multimedia Conferencing Systems: This technology can deliver full-motion Multimedia Conferencing from your PC. Desktop systems have been engineered to accommodate the
industry's requirements for standards-based videoconferencing. There are systems available that deliver high quality at a low
cost. These systems provide H.323 voice and video, as well as
applications sharing. They offer easy installation and many have no add-in boards to
install or bulky hardware to place on your desk.
Set-top Multimedia Conferencing Systems: Set-tops are complete Multimedia Conferencing systems designed to sit on a monitor. Useful in small boardrooms and other small group scenarios. Are often maintained on a cart, making it possible to roll them
around for use in different rooms. Have excellent video quality and work well with auxiliary
equipment, such as document cameras, to enhance videoconference presentations.
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Types of Multimedia Conferencing Systems (cont.)
Integrated Multimedia Conferencing Systems: Integrated systems are group conferencing systems most often used in
conference rooms or classrooms with multiple participants.
This type of system usually consists of a centralized location
for wiring and processors to be routed. The main camera,
displays and peripheral video sources are usually mounted in
the main conferencing area.
These customized configurations are normally equipped with
multiple features and also allow for the videoconferencing
room to be used for other various functions as well.
Most integrated systems available today are capable of
connecting both H.320 (ISDN lines) and H.323 (IP/LAN).
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