Monday, 21 July 2008
Video Conferencing - The Power of SIP
One such protocol, or rule that sets out how communications should be initiated and terminated, is the Session Initiation Protocol (SIP). SIP is used for VolP calls, video conferencing, and for other online activities such as instant messaging, status updating, and online gaming. It is likely, therefore, that most of us would have had some contact with it, even if we were not previously aware of its existence, and it remains the most widely used protocol for VoIP.
"SIP is a 'session-control' that makes it possible to start and end video and voice calls," says Sean Holohan, managing director for voice, video and networking equipment distributor Videnda Distribution. "Other protocols, such as H.323 were also capable of doing this. However, SIP actually brings together other elements that allow greater flexibility during the call session."
The H.323 protocol has been the video transmission standard for some time, and continues to be used widely in online video. However, for the purposes of video conferencing, and the added functionality required for such activities, H.323 does not have the capabilities required to provide such elements as placing calls on hold, transferring them to other users, or creating conference calls.
SIP is the standard that facilitates this, allowing different systems to communicate with each other, and permits better integration between different devices, such as IPtelephones, computers, mobile devices, and so on. As IP communications are server¬based, as all internet communication is, the server takes the place of the traditional telephone exchange, and deals with all the video and voice data traffic involved in the call.
As video conferencing becomes increasingly sophisticated in terms of how it functions, SIP is, in turn, becoming the standard on which new video conferencing technology is based. Developers such as Polycom and Microsoft are using SIP to create new hardware and software solutions that will increase the scope of what is possible with video conferencing, while improving the functionality of existing solutions.
Multimedia applications appear to have been one of the main beneficiaries of SIP. Video conferencing sessions are increasingly about much more than just video and voice communications. The ability to share documents, make presentations, to establish break¬down groups, to restrict access, and so on, are all essential components of the average video conferencing set-up. In an increasingly complex developmental environment where face-recognition software can make a camera track its subject and highlight specific parts of a video link, as well as providing high-definition links, ensuring that connectivity is straightforward is an essential part of the session control.
While SIP helps to ensure that video conferencing can be achieved in the most efficient way possible, it will also help to shape future developments. The aforementioned multimedia aspects of communication are here to stay: in many ways, they are more useful than if an audience was physically present in the conference room, as presentations, documents, spreadsheets and other tools can be accessed quickly and presented clearly. There are, however, other developments taking place in video conferencing that will require reliable connectivity to ensure that they become viable.
"Telepresence is part of the way we are developing video conferericing at Sony," says David Byme, channel manager for Sony Ireland. "Up to now, video conferencing has entailed looking at a screen or a TV image. Whilst this has been an effective way of communicating between different locations, we are now looking at breaking down those physical barriers further. Providing floor-to-ceiling imaging will effectively create a boardroom environment that is as 'real' just video and voice communications as can possibly be without the physical presence of the participants."
In a way, SIP is helping video coilferencing to become the 'boardroom 2.0', in so much as communications are effectively easier to achieve in organisations with personnel scattered across multiple locations. If, as Sony wants to achieve, the aspect of taking to a 'screen' rather than a person is changed to become as realistic as possible, then video conferencing will become indispensable as a communications tool.
Realising the possibilities of IP communication for both video and voice is one thing; having the infrastructure to support such developments is another entirely. As SIP continues to help make video conferencing feasible throughout business, and even within the home, it is likely to become the standard for even further developments.
IP Telephony Supplement - Media Planet - Published with Sunday Times - July 20th 2008