IP's new way of dialing

Ethernet can carry voice traffic, but don't dump your standalone phones just yet
By Stephen Lawton

Cutting IT costs, improving network management, and reducing support are high on the agendas of many network managers. One increasingly serious approach to gaining these benefits entails some daunting challenges: merging telephone and data networks to carry voice traffic over IP.

Vendors claim that IS managers could reduce their support and infrastructure costs by leveraging their existing Ethernet networks. In a "green field" environment (such as a new building that has no infrastructure yet), that means not laying a second set of phone cables; in an existing building, it could include eliminating expensive PBX systems. And telephone-support personnel might become unnecessary if telephone systems become just another application on the network, according to George Hunt, principal analyst for wide-area networking at Dataquest in San Jose, Calif.

Conceptually, IP telephony is not new; products that let users make calls over the Internet have been available for several years. But today's offerings are more robust, and they introduce new methods for putting voice, data, and video on packet-based IP networks.

From a technical standpoint, there are two distinct approaches to IP telephony: putting voice on Ethernet, or using a traditional twisted-pair telephone line for voice and Ethernet for the telephony control codes.

The arguments for either tactic are essentially the same. Using an existing network leverages the user's investment and adds only minimal traffic to the Ethernet network. Generally, a server running Microsoft Windows NT or Unix is connected to the network that serves as the PBX and manages all calls. In some cases, the existing PBX continues to be a backup in case the server fails.

Both approaches provide the option for one other significant cost saving: essentially free long-distance phone calls, achieved by using the Internet rather than the public switching telephone network (PSTN).

Adding capabilities could also improve user productivity. For example, Latitude Communications Inc. has an IP telephony application that provides a "virtual conference room."

Using a conferencing server attached to the network and phone system, this IP telephony application can create one or more conferences with up to 120 phone connections. It can save time in setting up and running meetings, make the meeting's contents available to users unable to attend, and let trainers create sessions for one or many students from a conference library, says Glenn Eaton, vice president of marketing at Latitude in Santa Clara, Calif.

The pitch for IP telephony is compelling, but questions remain. Do the cost savings justify ditching an established business tool in favor of an emerging technology? Is the voice quality adequate for business purposes?

In this area of technology, even more than most, you don't know what you'll get until you try. KIH On-Line Inc., an ISP (Internet service provider) in London, Ky., is testing Lucent Technologies Inc.'s Internet Telephony system, with the intent of providing Internet phone calls to its customers, according to Carlos Carpenter, KIH president. The ISP has two gateways in place and is installing five more.

Currently Louisville-based customers can call the London technical-support center by dialing the Louisville point of presence (POP), says Chuck Neville, president of Neville Technologies, a systems integrator in Shelbyville, Ky., that is working with KIH and Lucent to install the IP telephony system. Neville characterizes the initial results as "good-quality communications," but he adds that there are few router hops across Kentucky. Router hops add delay to the voice, and as long as the delay is less than 300ms, the voice quality should suffice. Above that threshold, the quality will be inadequate for business purposes.

Several IP telephony hardware suppliers call the quality of voice over IP "near long-distance quality." The voice data is compressed from roughly 64KB to 8KB when transmitted over a network. In subjective terms, the voice is somewhat softer and not as clear as a traditional telephone connection, but it is superior to making an intercontinental call by satellite.

Two styles of delivery
Moving to IP telephony is a serious decision, no matter how you do it. An example of the single-network approach, with voice and data using the same Ethernet network, is PhoNet Communications Inc. A data PBX and a gateway board are housed in a Microsoft Windows 95 or NT server, which can support up to four four-port cards, says Frank Quinn, vice president of North American operations for the Herzliya, Israel-based company. When multiple servers are connected, they can share loads and provide failover capabilities, he says, and adding more servers increases the phone-line capacity, making the system scaleable.

On the downside, Quinn says, an environment that does not support failover capabilities could lose its phone system in the event of a server crash or network failure.

In contrast, using existing phone lines eliminates concerns about voice becoming a bandwidth hog or losing service if the server fails, according to Claus Tarstrup, product-marketing manager at TouchWave Inc. in Sunnyvale, Calif.

TouchWave's system lets voice traverse the existing phone network, whereas control codes--such as hold, transfer, parking, and similar telephone functions--are transmitted over Ethernet.

One limitation that some IP telephony systems face occurs with moves, adds, and changes. In TouchWave's design, for example, users can be added or changed from a Web-based interface, but the system has to be rebooted for the changes to take effect. During the time the server reboots, "everyone has to hang up," Tarstrup says.

And any IP telephony system will require someone to open every connected PC and install and configure a LAN telephony card. This could be painful for a large company with lots of phones and computers. While that system is being upgraded, the phone will be offline unless the system continues to use the existing wired phone network. Similarly, when cards are added to the server, the server would have to be turned off. That too could interrupt phone service for all but systems with hot standby or those that fail over to a PBX.

Convincing the bean counters
Even when a solution makes technical sense and can improve user productivity, finance officers may be unwilling to invest in IP telephony, says Kerry Hawkins, sales and marketing vice president at Vienna Systems Corp., a manufacturer of IP telephony systems in Kantana, Ontario. These managers may have to be shown that IP telephony will pay for itself out of savings on long-distance calls and other phone costs.

Another line item where cost savings are being realized is in the installation of trunk lines. For example, End User Computing Inc., a systems integrator in Toledo, Ohio, had 11 employees, each with a trunk line to the desktop.

The company had investigated traditional PBX options, which offered the requisite services but at too high a price, says Tom David, facilities manager at End User. Additionally, changes or updates to the system would have required a field technician to update the system from a dedicated terminal in the phone closet.

Eventually the company opted for an IP telephony solution from AltiGen Communications Inc. The AltiServe system includes three Quantum server boards in a Windows NT-based desktop chassis; each full-length ISA board supports up to 10 telephone extensions.

A traditional PBX would have required roughly $60,000 in hardware alone, and it would have tied the company to a proprietary system, David says. The total price for the dedicated NT server plus the AltiGen hardware and software was roughly one-third the initial PBX costs. Additional benefits came from the simplified administration of the telephone server and the capability of expanding the system using commodity NT servers.

David admits that End User has significantly more technical expertise than non-IT companies. But except for setting up the Web-based administration utility, he says, putting together the AltiGen server was "no more difficult that installing a sound board."

Despite the implementation uncertainties, IP telephony will make inroads because it saves money by reducing costs and lets vendors and carriers increase revenues, says Dataquest's Hunt.

Brett Azuma, Dataquest's principal analyst for public network equipment and services, says that in the next five years he expects to see lower access charges for long-distance telephone calls, improved voice quality, and significantly faster networks. This period will see expansion of IP telephony into lower-income countries, greater functionality for the enterprise, and a focus on support infrastructure and applications.

Azuma says that most potential users will be large companies and next-generation telephony companies. "It's not a market for the faint of heart," he says.

For ISPs, voice over IP will become a given during the next few years, adds Don Miller, chief networking services analyst at Dataquest. "You must have this in your portfolio," he says. "If you don't, you're dead meat."

 


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