7.24 Video Conferencing

Web conferencing enables a company to conduct live meetings, training, or presentations via the Internet. Each participant sits at his or her own computer and is connected to other participants by one of two methods. Either they install downloaded software, or they enter a predistributed password to access a meeting held on 'third-party premises'.

Web conferencing is increasingly used by companies of all sizes, and offers:

1. More efficient and effective meetings.
2. Reduced or zero travel time and cost.
3. Better communication with customers, partners and vendors.
4. Reduced sales cycle time and costs.
5. Improved technical support and customer service.
6. Better follow up on staff training.

Types

Video conferencing employs voice over IP (VoIP) technology and is of three types:

1. Ad hoc conferencing: set up over the telephone. The person hosting the conference calls an attendee, presses the Conference button, and a one-to-one telephone call is expanded to accept other participants, who are then called by the meeting host. The Meet Me model is similar but uses specially designated telephone numbers. Administrators set up these numbers by configuring the local phone system to forward calls to a conference server. Once in operation, the conference server manages calls independently of the larger telephone system. All who have the designated numbers can join the conference, but are commonly asked to identify themselves.

2. Reservationless: still fairly basic and commonly set up with the telephone keypad. Here the meeting organizer specifies a meeting name and creates a meeting identifier. The person hosting the meeting generally dials into the conferencing system and creates a meeting instance via the Interactive Voice Response (IVR) system.

3. Scheduled conferences: offers the fullest facilities and is set up in advance, at times mutually convenient to attendees and when the Internet lines are not likely to be too congested. Meetings are arranged through the Internet ( web browser), the telephone, or are integrated with email and calendaring systems like Microsoft Outlook.

Practicalities

Video conferencing is straightforward to participants, and companies offer an easy-to-use service that is generally categorized under three endpoint options. {10} An endpoint option is a combination of camera, codec and screen. Codecs are coding and decoding programs.

1. Desktop video conferencing: a web-based, software-client-based, and dedicated standalone video appliance or a video-enabled IP telephone designed for the single user.
2. Room-based: employing one or more large screens and designed for groups.
3. Telepresence: as 2. but including audio and visual enhancements of furniture, sound and lighting arrangements to give participants the feeling that they are sitting across the table from their colleagues. Telepresence can also be used in areas hazardous to human beings. {9}

Several components are required:

1. Cameras and video conferencing codecs to encapsulate and decapsulate video images at the endpoints,
2. Screens to display images,
3. Bridges, gateways and video conferencing multipoint control units (MCUs) for interconnecting multiple endpoints, transcoding between different codec encapsulations, interconnecting video conferencing systems with other applications, policy and security enforcement, and external connectivity across network boundaries,
4. Management tools to schedule of video conferencing sessions and control session quality,
5. Data network resources to deliver video packets between endpoints and other components.

Technicalities

Video conferencing employs complex technology, the details of which are the concern of engineers who set up the systems, and the technician who operate them. In outline, however:

VoIP

Voice over Internet Protocol enables calls to be made over a broadband Internet connection rather than a regular (or analog) phone line. VoIP is implemented using both proprietary and open protocols, and is a feature of various systems, particularly those of long distance telephone calls, video conferencing and Skype. The analog voice signal is digitized, encoded, divided into packets and sent as Internet Protocol (IP) packets over a packet-switched network. The same steps in reverse order convert the packets into audio signals at the receiving end. Video and data are handled separately, but in a similar way. Extra protocols are added for transmission in congested condition, and transmission made secure by various encryption methods (e.g. Secure IP, Secure Voice over IP and Secure Voice over Secure IP).

Audio and video information has to be compressed: there are several formats in common use. {4} {5}

Voice and video packets are sent under Realtime Transport Protocol (RTP) in which the following also play a part:

H 323 (handles call signaling and control, multimedia transport and control, and bandwidth control)
SCCP (Signaling Connection Control Protocol)
SIP (Session Initiation Protocol)
MGCP (Media Gateway Control Protocol)
MEGACO (Media Gateway Control Protocol)
RTSP (Real Time Streaming Protocol)
AVC (Audio/Video Compression format)
RTCP (Real-Time Transport Control Protocol)

Conferencing System Components

Five components are needed:

1. User Interface, which itself consists of:

    a. scheduler to arrange conferences in advance.
    b. web portal accessed through a browser on the client PC.
    c. voice user interface (VUI) to manage participants.
    d. a meet me or conference button on the telephone keypad.
    e. An interactive voice response (IVR) system to deliver voice prompts to attendees.

2. Conference Control, which interacts with the User Interface and the scheduler to create meetings, insert and remove attendees, and connects them them to the IVR according to user input.

3. Control Plane, which contains the signaling stacks, controls incoming and outgoing connections, and negotiates the session parameters.

4. Media Plane, consisting of audio and video mixers, which have inputs and outputs for media streams.

5. Administrative Interface, which interacts with the four components above, and:

    a. sets resource allocation defaults.
    b. handles any overbookings.
    c. specifies the maximum meeting length of time.
    d. enables and defines the signal protocols.
    e. configures the system name.
    f. configures the audio preferences
    g. configures the videocapabilities and bandwidth limitations.
    h. adds and configures system users and the capabilities allowed.
    i. adds or updates recorded prompts.
    j. sets the system to an enabled or disabled state.

Services

Some of the better-known services:

System

Platform

No. of

Attendees

Secure

Access

Encrypted

Meetings

Pricing

Citrix


GoToMeeting

Windows

& Mac

<=15

yes

no

$49/month

Cisco


Meeting Center

PC, Mac, Linux,

Unix, Solaris

& iPhone

<=25

yes

no

$49/month

Adobe


Connect

PC, Mac, Linux,

Unix, Solaris,

& iPhone

<=1500

yes

no

$45/host/month

or $0.32/user/minute

Intercall


Unified

Meeting

Windows & iPhone

<=120

yes

yes

$59/host/month

or $0.17/user/minute

Microsoft


Office

Live

Windows

<=1250

yes

no

$16/user/month (prof)

or $4.50/user/month

IBM


LotusLive

Meetings

Windows,

Mac & Linux

<=2000

yes

yes

p.o.a.

Zoho

Meeting

Windows

<=100

yes

yes

from $12/month (5)

to $49/month (100 users)

DimDim

Windows,

Mac & Linux

<=100

yes

no

$0-33/user/month

Elluminate

Windows,

Mac & Linux

50-400

no

no

$50/month

All

Conferencing

Windows,

Mac & Linux

<=99

yes

yes

from $19/month

Buddy

Meeting

Windows,

Mac & Linux

<=10

no

no

free

Fuze

Meeting

Windows,

Mac & Linux

55+

no

no

$10-69/month

Glance

Windows,

Mac & Linux

100

no

no

$50/month

NetViewer

Windows,

Mac & Linux

<=200

no

no

$30/month

omNovia

Web

Conference

Windows,

Mac & Linux

2-5000

yes

yes

$40/month -

$8.10/seat

Google

Open

Meetings

Windows,

Mac & Linux

<=25

no

no

free

Tokbox

Windows

& Mac

20-25

-

-

free APIs

for developers

VenueGen

Windows

<=500

no

no

$0-790/month

WebEx

Windows,

Mac & Linux

<=25

yes

yes

$49/month

Web

Huddle

Windows,

Mac & Linux

small

no

no

free while beta

Yugma

Windows,

Mac & Linux

<=500

no

no

$0/10 users/month to


$160/500 users/month

Questions

1. Why is video conferencing becoming an important aspect of business life?
2. Describe the three types of video conference, and the three ways it may be set up.
3. What components are required for video conferencing? Show how they interact.
4. Give some account of Voice over Internet Protocol, and the other protocols involved in video conferencing.
5. Consider three popular video conferencing services and compare their features in detail.

Sources and Further Reading

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