VOIP Technology Could Make Communication Systems More Efficient

The Voice Over Internet Protocol (VOIP) technologies that Harvard may adopt for phone communication in the future are so new that no university currently relies on them.

In interviews last week, experts on the technology said VOIP is a vastly more efficient alternative to traditional telephone service.

But they say it is still in its infancy. While VOIP is being tested by corporations and telecommunications companies around the world, few have begun to implement it.

Reached on his VOIP phone--one of eight that University Information Services (UIS) is testing--Leo D. Donnelly, a UIS senior technical consultant, says the technology is not yet perfect.

"No major company that I know of is replacing everything," says Leo D. Donnelly, a senior technical consultant for UIS. "It's too soon. The hardware's changing rapidly, the software's changing rapidly."

If it occurs, Harvard's transition to VOIP is still years away--Verizon Communications' contract to run the machinery that routes calls on Harvard's telephone network does not expire until 2003.

However, Harvard has begun to purchase equipment from Cisco Systems to roll out VOIP to selected users on a trial basis.

VOIP technology makes more efficient use of telecommunications resources--meaning that the technology would save money for phone companies and, ultimately, consumers.

Currently, telecommunications companies around the world maintain two separate networks--the Internet for data, and the telephone network, sometimes called the "Public Switched Telephone Network" (PSTN), for voice calls.

These networks work very differently.

The PSTN--used for phone calls today--makes a direct connection between a user and a caller.

A large portion of bandwidth is reserved for that phone call--irrespective of what you are saying or how fast you say it. If you were to leave the phone off the hook and not speak at all, the telephone network would dutifully transmit the sounds of silence.

In the Internet age, this method is grossly inefficient.

With VOIP, telecommunications companies can break down your voice into packets of digital data and then transmit them over the Internet. Using compression technology, VOIP telephone calls require eight times less network resources to complete a call.

In addition, VOIP phones only transmit sound when you are actually speaking into the mouthpiece, further reducing the bandwidth necessary for voice communication.

Another reason that telecommunications companies are so excited about VOIP technology is that it saves them the burden of maintaining two separate communications networks. If telephone calls were placed digitally over data networks such as the Internet, telecommunications companies (including UIS) would have to maintain and upgrade a single network instead of two.

By making phone use more efficient, VOIP technology could reduce the cost of phone use for telecommunications companies and consumers.

The flip side of using data networks for phone calls is that data networks are typically far less reliable than their telephone counterparts, which reserve a set amount of bandwidth for each telephone conversation.

Normal telephone calls are almost always completed and do not become disjointed because of a surge in traffic over the telephone network.

However, if Harvard's data network slows suddenly while a student is downloading a website, the student simply has to wait an extra second or two for the page to load. If the same were to happen during a telephone call, some part of the conversation would not get through or would be delayed to such an extent that normal conversation would be difficult. In fact, studies have found that delays of more than a half a second in voice conversations would render VOIP essentially useless.

The main problem with VOIP so far, says Donnelly, is that it doesn't handle sudden bursts of traffic over the network very well. If your roommate were to begin downloading a large file while you were talking on the phone, your conversation might begin to break up.

As a result, scientists are putting a tremendous amount of effort into developing quality of service technologies that can give priority to voice traffic when network slowdowns occur. According to Donnelly, once this technology is fine-tuned, VOIP should become ubiquitous both in national data networks and private intranets such as Harvard's.