EPL011-Ioannou

Nicos IoannouNicos Ioannou

University of CyprusUniversity of Cyprus

15/2/200415/2/2004

Real Time Distance Education Real Time Distance Education Systems and TechnologiesSystems and Technologies

ContentsContents Introduction Video Conferencing systems

Endpoints MCU, Gatekeeper, Gateway

Data Collaboration tools VRVS Net meeting

Streaming technologies Live Streaming Video on Demand

IntroductionIntroduction

Provide information about Real Time Provide information about Real Time Distance Education systems and Distance Education systems and services services

Share knowledge and experiences Share knowledge and experiences among participantsamong participants

Video ConferencingVideo Conferencing EndpointsEndpoints

Multipoint Control UnitsMultipoint Control Units

GatewaysGateways

GatekeepersGatekeepers

VideNet and Global Dialing SchemeVideNet and Global Dialing Scheme

EndpointsEndpoints Software-based

Generally slow and non-standard; not very satisfactory.

Examples: Microsoft NetMeeting Hardware-based, plug into PC USB Port

Newest approach; will become ubiquitous Examples: Polycom ViaVideo, VCON ViGo.

Hardware-based, PCI-bus cards install inside PC Added features and controls, beyond USB systems. Examples: Zydacron Z340, VCON Escort 25.

Hardware-based, standalone, no PC involved Easiest to use, best quality. Example: Polycom Viewstation

Standalone EndpointsStandalone Endpoints

Set-topSet-top 500, 800500, 800

DesktopDesktop 10001000

Complete systemComplete system 2500, 6000, 70002500, 6000, 7000

Multipoint Control Unit Multipoint Control Unit (MCU)(MCU)

Allows more than two people to be in a videoconference.

May be physically located anywhere on Earth. Functions as an Internet server for

videoconferencing. Every person’s audio is always heard by all

others. Video from the person who talks loudest is

seen by all. Multiple MCUs may be cascaded together for

larger videoconferences. Or used separately for more simultaneous videoconferences.

GatewayGateway

Joins H.320 ISDN video calls with H.323 Internet video calls.

Calls may be initiated from either side.

May be physically located anywhere on Earth.

Multiple gateways may be used for more simultaneous calls.

GatekeeperGatekeeper Controls all MCUs, gateways and clients in its

“zone”. A zone is any collection of H.323 devices you choose to work closely together. The devices may be physically located anywhere on Earth.

There can be only one active gatekeeper in a zone.

May be physically located anywhere on Earth. May be physically located in an MCU, a

gateway, a router, or a PC. But it is independent of them.

Provides calling with “telephone numbers” and nicknames, instead of IP addresses. A gatekeeper is analogous to a domain name server, in this sense

VideNetVideNet A test-bed for exploring issues A test-bed for exploring issues

associated with the creation of the associated with the creation of the global integrated video/voice over IP global integrated video/voice over IP environmentenvironment

An interconnected network of h.323 An interconnected network of h.323 zoneszones

A community of users sharing A community of users sharing informationinformation

video to every person on Earth ...

Global Dialling SchemeGlobal Dialling Scheme E.164/tel.no. integrationE.164/tel.no. integration Implemented by present gatekeeper Implemented by present gatekeeper

technologytechnology

Data Collaboration Data Collaboration • Allows remote participants to take Allows remote participants to take

control of the application or desktop on control of the application or desktop on the host computer.the host computer.

• Provides additional features such as Provides additional features such as instant messaging, whiteboard, chat, instant messaging, whiteboard, chat, and file sharing.and file sharing.

• Provides a persistent virtual workspace.Provides a persistent virtual workspace.• Provides tools such as agenda, task list, Provides tools such as agenda, task list,

project planning, calendar, discussion, project planning, calendar, discussion, outliner, etc…outliner, etc…

Data Collaboration Tools Data Collaboration Tools VRVSVRVS

From the Physics communityFrom the Physics community Tens of reflectors, thousands of users, Tens of reflectors, thousands of users,

thousands of hours usedthousands of hours used SchedulingScheduling

Netmeeting, MessengerNetmeeting, Messenger Free from Microsoft windowsFree from Microsoft windows

VRVS ToolVRVS Tool

StreamingStreaming Media Media

Streaming is the one-way delivery of digital Streaming is the one-way delivery of digital content from a streaming server to a streaming content from a streaming server to a streaming client in a continuous, paced, and controlled client in a continuous, paced, and controlled flow.flow.

Streaming alleviates the need to download an Streaming alleviates the need to download an entire media clip as a file.entire media clip as a file.

Live events don’t exist as a file yet!Live events don’t exist as a file yet! Allows playing to start before download is Allows playing to start before download is

completedcompleted Protects copyrightProtects copyright

StreamingStreaming Media Media

Live StreamingLive Streaming Μετάδοση σε πραγματικό χρόνοΜετάδοση σε πραγματικό χρόνο Όλοι οι clients βλέπουν την ίδια ροή Όλοι οι clients βλέπουν την ίδια ροή

ταυτόχροναταυτόχρονα Μετάδοση με multicast και unicastΜετάδοση με multicast και unicast

Video on DemandVideo on Demand Μετάδοση αποθηκευμένων αρχείωνΜετάδοση αποθηκευμένων αρχείων Οι clients παρακολουθούν τη ροή κατ’ απαίτησηΟι clients παρακολουθούν τη ροή κατ’ απαίτηση Μετάδοση με unicastΜετάδοση με unicast

Live StreamingLive Streaming

PictureTel

Streaming server

PictureTel

ΔΙΚΤΥΟ ΚΕΑΔPlayer

<150Kbps

>150Kbps

Sure Stream

Sure Stream

Encoder

Player

Video on DemandVideo on Demand

PictureTel

PictureTel

ΔΙΚΤΥΟ ΚΕΑΔ

Player

Player

Video On Demand Server

Q&AQ&A