by Stewart Hersey, MA Ed

On-demand audio conferencing has emerged as one of the most compelling ways to improve productivity, streamline business processes and collaborate more efficiently. Enterprises are beginning to move to single; converged IP networks that enable a host of new conferencing services and applications that promise to make peoples' lives simpler and more productive.

The success of today's corporation depends on investing in new growth opportunities while lowering costs as much as possible. The ability for a business to communicate regularly with all its constituents-employees, customers, partners, suppliers and shareholders-in an effective, immediate and cost-effective manner is a critical element of success. This is why on-demand audio conferencing has emerged as one of the most compelling ways to improve productivity, streamline business processes and collaborate more efficiently within a network. Enterprises are beginning to move to single; converged IP networks that enable a host of new conferencing services and applications that promise to make peoples' lives easier and more productive, at dramatically lower costs. According to Frost & Sullivan, the U.S. audio conferencing total market revenue is expected to reach US $3.13 billion by 2011.

Audio conferencing using Voice over IP (VoIP) works very similarly to a traditional conference call using an analog telephone. In a conference call, callers connect to a conference bridge, a server that allows multiple people to talk to each other. VoIP audio conferences use the same principle -- callers connect to a conference bridge via their telephones or their computers. If a business uses a packet-switched network for its telephones, calls from outside of the company can still connect the conference bridges. External lines may connect directly to the bridge server, or external calls may reach the server through a VoIP network.

Work in the Session Initiation Protocol (SIP) standards community is progressing, promising robust and increasingly interoperable feature sets. Conferencing is a natural for SIP, since SIP sets up sessions of any media type (audio, IM, video, data). SIP negotiates the session parameters and capabilities using Session Description Protocol (SDP), and allows multi-vendor clients to initiate ca onference. Since both of Dialexia’s flagship products, Dial Office (IP-PBX) and Dial-Gate (softswitch) are based on SIP, conferencing is an advanced feature that is native in either case.

Basic centralized multipoint multimedia conferencing is supported natively by Session Initiation Protocol. Signalling goes to a central User Agent called a 'focus.' This simple ad-hoc conferencing was defined in draft-ietf-sipping-cc-conferencing-07. This draft describes how a conference-aware endpoint can create a conference, adding other participants using SIP. One approach is to utilize an offer/answer exchange to change the bandwidth parameter within the SDP. This works, but re-invites flow through all proxies in the route and the messages may be quite large, since the whole SDP is transmitted.

Incorporating on-demand VoIP audio conferencing today means enterprises have more control over the conference call experience with minimal overhead. Because the conference call travels over IP networks, enterprises can use the Internet to provision, in real-time, new accounts, view billing information, initiate and terminate calls, notify conference attendees via E-mail, manage rich information and conduct many more functions that were originally initiated using a touchtone pad on an office phone. This flexibility is advantageous as audio conferencing increasingly becomes the essential collaboration tool driving new levels of productivity, competitiveness and profitability for enterprises.

The eventual transition to SIP is likely to be driven by reasons such as: advanced conferencing scenarios, security, FW/NAT traversal, federation between security domains, and media mode transitions from chat into voice to video. The ad-hoc capability built into many of the voice conferencing applications today has certainly driven increasing interest in enterprises implementing their own viable conferencing solutions. According to Gartner, through 2006 enterprise adoption of conferencing will remain less than 20%, with penetration after that increasing markedly to 70% by 2008. Not coincidentally, these projected timelines match the progression of SIP conferencing standards.

VoIP is going to change the conferencing world in three ways. First, VoIP introduces the ability — and, therefore the need — to enable conferencing between a variety of endpoints, not just what we know as our traditional phones. Secondly, VoIP introduces the potential for a much richer conferencing experience as each vendor begin to offer wideband conferencing options. Third, VoIP will significantly accelerate the transition from conferencing services to customer-owned conferencing applications. Why then pursue an economical solution like VoIP and then continue to support high, pay-as-you-go conferencing services? Companies will pursue solutions consistent with the promise of VoIP — cost-effective solutions that can leverage their existing network assets and scale economically to easily support any number of conferences, participants, and endpoints.

3-way conference calls are supported in Dial-Office and Dial-Gate depending whether the User Agent can handle the request. Dialexia is now developing a Conferencing Bridge that is able to support multiple conferences with multiple participants. Callers can call in to join the conference and they could also be invited to join it. Using an Interactive Voice Response (IVR) system, the Conferencing Bridge will welcome the participants and guide them to join the conference that they are interested in. The alpha release is expected by the end of January. The final release is scheduled for June.