When voice met data

27 Feb 2003

The notion of using internet protocol (IP) networks for carrying voice has been around since the early-Nineties but to date most of us are using standard voice solutions. So what has been holding up voice over IP (VOIP) as it is generically called?

“Nothing really,” says Gerry Keleghan, systems engineer with Cisco Systems. “In terms of revenue it is steady and coming from various sources.”

Ray O’Connor, sales manager for 3Com, tells a similar story: “The two development areas would be converged voice and data solutions and wireless. They are still very much in development but we are seeing products maturing and seeing real customers use real solutions.”

Both men point out that VOIP means different things to different people. “It’s important to distinguish between VOIP, IP-enabled PBX [private branch exchange] and IP telephony,” explains Keleghan. “VOIP is the transport of voice data over an IP network. A lot of enterprises have been using this technology for about five years now. It’s popular and it’s mainstream. For customers with remote offices it’s the preferred option for getting voice across a wide area network link.”

IP-PBX, says Keleghan, is becoming very popular with companies who want the advantages of VOIP but want to keep their existing hardware. Many vendors have stopped research into TDM (time division multiplexing) PBX systems and are putting resources into the IP-enablement of their products. Users can attach IP telephones directly to the PBX and can connect to remote sites using VOIP technology. However, for VOIP and IP-PBX there is little or no ‘intelligence’ involved.

“The third area is IP telephony,” he explains. “This is a client-server-based telephony application, similar to today’s web applications. Servers reside at the core and the client can go anywhere. So IP phones can connect to a network and use the features of IP for connectivity and get their service from a central server cluster. The phones each have full IP stacks and the call control agent, ie the server, is only involved in setting up the call and tearing it down. The voice traffic itself passes directly between the two phones.”

IP telephony offers users several advantages, one of which is ease of management. “The biggest benefit that sells IP telephony is ‘moves, adds, changes’,” says O’Connor. “Management of a PBX is typically outsourced so if a company wants to move a phone around it has to call in someone, wait until the engineer turns up and pay lots of money.”

However, because the telephone contains IP information, when workers move desks, they can simply carry their old phones with them, plug them into the network and have their calls automatically routed to their new locations. Other changes or additions can be made through a web interface.

“The phone itself becomes an appliance on the LAN [local area network] so you only have one network,” says Keleghan. “Voice is simply another application. This is what we term a converged office solution. It’s a notion that all applications are carried across one network with a single wiring infrastructure, which in itself can give cost savings.”

But with voice sharing a network with other applications such as SAP, customer relationship management and so on, isn’t there a risk of capacity? “Absolutely not,” says Keleghan. “A voice call between two phones uses 80Kbps while most users have 100Mbps full duplex to their desktop. Most LANs are all-switched infrastructures and some have up to 256Gbps on the backbone so voice consumption is minimal.”

Keleghan also points out that PBXs have a limitation on how many calls they can handle simultaneously. With IP telephony, there is no such limitation.

As to the question of the future of IP and voice, Keleghan agrees that the industry is on the crest of a wave. “The take up is strong, although we are obviously seeing a slow down because of the business environment. But because of the cost saving potential, there is a lot of interest from corporate customers. We are getting most interest from greenfield sites, customers looking at call centre applications, customers considering upgrades to their PBX and customers with a centralised model,” he adds.

O’Connor agrees that the best is yet to come. “As with many things, the US is ahead of us but things are really heating up. Most analysts say that by 2004 the different forms of VOIP will account for 50pc of the worldwide market. Take up here has been slower because of the business environment. It’s all very well to have the technology to do things but it has to make business sense. There is a gradual move to IP telephony but how quickly that will happen depends on the market,” he says.

Keleghan agrees: “People aren’t going to rip out their PBXs just because there is new technology. There have to be key benefits for customers.”

By David Stewart