By Anita Devasahayam
September 5, 1998
The MCS 'generations gap'
SO WHAT is it about USM's Multimedia Conferencing System 4.0 (MCS) that differentiates it from the rest of the pack?
According to the head of the network research group at USM, Sureswaran Ramadass, two concepts -- ``RSW control criteria'' and a distributed processing method -- place the product two generations ahead of its closest competitor.
He claims that other vendors have begun to follow in their footsteps by introducing similar concepts that were pioneered by Sureswaran (Sures) and his research team.
``They are beginning to catch on the concept that you need different things to do different functions, but they are talking about it and have not implemented it,'' he claims.
MCS' most powerful feature that places it above traditional video-conferencing systems is its provision for communications beyond the typical point-to-point or point-to-multipoint connections.
Being a client/server based system which supports distributed network entities, MCS allows up to 60 users per server, and the number of servers are scalable. The unlimited multipoint-to-multipoint interaction means that users located across different LANs can interact with each other.
``You can have 10 people here, 20 there, 30 at a remote site, 60 even further away -- and they all can take part in the conference,'' says Sures.
However, he concedes that there is a time lag when using MCS over long distance copper cables.
``Time lag will occur unless you have a leased line at all points. You can avoid it if you set up the network yourself. But if you use a network you can't control, such as the Internet, then there is a time lag,'' he admits.
Unlike other desktop video-conferencing systems, MCS does not hog processing power when used, says Sures. It only uses 16% of CPU capacity, allowing the rest of the CPU to be freed for other tasks.
``This means you can do other work like writing reports or pull out relevant information from your system while participating in video-conferencing session,'' he claims.
He adds that the advantage of a distributed network entity is that it allows the IT department to retain its legacy network and use it to support multimedia video-conferencing.
This is possible because MCS uses the standard IP (Internet Protocol) language for communication. Being hardware- and network-independent, users can run MCS over any network from X.25 and Ethernet, right up to ATM (Asynchronous Transfer Mode).
It also supports common operating system environments such as DOS, Windows 95 and Unix.
Adds Sures: ``The amount of money invested in setting up a networked environment just to accomodate one product is uneconomical. We thought of that when we were developing MCS.''
Four main entities
MCS is made up of four distributed network entities -- the server, the client, the multiLAN IP convertor (MLIC) and the data compression entity. All these entities operate independently of each other.
If a user chooses to add an entity at a later date, the server will reconfigure itself to integrate the new entity and include its functions.
``The reason we did this was so that we can easily integrate new features or support for our product as soon as technology changes. The distributed network entity allows you to do anything,'' claims Sures.
The server entity's job is to communicate with all other entities to synchronise and coordinate the system. If the MLIC entity is integrated, the server provides a routing table for MLIC to run. The server entity is based on an open standards and is not tied to any proprietary system. You can migrate it to any client environment, even the Apple Macintosh.
Sures created the ``RSW control criteria'' which is housed in the server entity to cater to the high bandwidth required by multimedia conferencing. ``It also gives the conference a sense of order,'' he says.
In a multi-server conference, there will be communications between the servers from each LAN. The server within the LAN in which the conference is started will pass all information regarding the conference to other servers. These include the chairman, the control criteria used, the participants invited from each LAN, and also the queue information.
Each conference has to be given an ID in the form of a name. The RSW control criteria is selected. Finally the conference server is selected. Once all this information is provided, another window will appear.
All the users of the conference server will be displayed. Users who are logged in will have their login noted at the end of their name. The chairman will select users he wants to invite for the conference. There is a status option to invite users either as participants or as observers. Participants can request and transmit audio and video. Observers can only listen to and watch the conference.
Client and data compression
The PC-based graphical enduser application client entity supports multimedia capture, multimedia playback, data packetisation for transmission and data reconstruction for receiving. It also communicates with the server to maintain the RSW control criteria.
MCS can transmit and receive audio and video in real-time and in full motion of up to 30 frames per second. It provides smooth playback, mixed commentaries and allows video streaming of VCR movies and recorded meetings.
It uses IGMP multicasting for efficient transmission of real-time multimedia data. Through multicasting, Sures' research team succeeded in removing interference caused to the other systems and servers by broadcast type traffic.
With full duplex audio and video transmission, the number of active sites during a conference is doubled, allowing three mini screens to be seen on a client's PC monitor.
MCS version 4.0 also uses a conference control criteria called Chairman Continuous Presence (C2P).
``With this, the chairman will always be active while one of the participants is active at the same time,'' Sures says, adding that participants can take turns among themselves to be the active site during a conference, allowing the chairman and an active site to talk to each other simultaneously.
Being compliant with Internet realtime streaming standards, MCS version 4.0 also includes the capability to stream multimedia data using the Real-Time Transfer Protocol as defined in the RFC 1889 specification.
The data compression entity provides realtime compression and decompression. It is particularly useful when bandwidth is an issue, especially over the Internet. The current algorithms supported include MJPEG, Intel INDEO 5.0, MPEG, H.261, YUV411 and VDO Wave.
Sures adds that the compression feature, which can be enabled or disabled by the user, caters for bandwidth constraints while conferencing over a wide area network (WAN). With the Real Time Protocol format, MCS can dynamically support multiple compression formats in future.
Through realtime conference updates, the chairman and all participants can be automatically updated on the latest status of the conference.
MultiLAN IP convertor
The MLIC makes video-conferencing over WANs possible by allowing multiple LANs to join in a conference simultaneously, via a WAN.
According to Sures, the role of MLIC is to multitask.
``It picks up a data packet, enscapsulates it and tunnels it to other sites across the WAN. At the receiving end, the MLIC there extracts it, transforms it and re-multicasts the packet over the LAN,'' he explains.
He adds that the implementation of MLIC can be done over either DOS, Windows 95 or Unix.
Sures says MCS is hardware-independent, but points out that different types of hardware yield different results.
``Different video capture cards give different results, although we support any Win95-compliant card.
``But some cards perform better than others, not because our system says so but because the technology is better. For instance, Philips cards are good. Similarily, some cameras work better with some cards. Even the lighting in a room transmitting the image affects how it appears at the other end,'' he says.
The minimum hardware requirement to run MCS is a Win95 multimedia PC with 16MB RAM, a network interface card, video capture card and a desktop video camera.
Multimedia Research Lab Sdn Bhd (Mlabs), which be marketing the product, is offering package deals.
For instance, the company will throw in a server for a purchase of a 10-user system.
``We'll configure it and it will be up and running in 30 minutes. But users are free to use whatever hardware they want,'' Sures says, adding that the starting price is RM67,000.
The MCS client application -- comprising video capture card, video camera, and full duplex card plus earphone set -- is priced at RM3,200.
Published in In.Tech, Star Publications (M) Bhd.
(C) 2000 Julian Matthews
& Anita Devasahayam. All Rights Reserved.
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