Voice Over the Internet

Talking Internet

Internet Protocol (IP) was designed for data files that can tolerate delays, dropped packets, and retransmissions. Voice traffic, in contrast, is delay-sensitive--which explains why it's usually carried over circuit-switched public networks. However, vendors have started selling software that converts voice into packets, and routers can use IP's UDP (user datagram protocol) spec to shunt those packets through the network.

Internet Service Providers are adding voice options to their services --including ANS Co+re Systems Inc. (Elmsford, N.Y.), BBN Planet Corp. (Cambridge, Mass.), Compuserve Inc. (Columbus, Ohio), Global Enterprise Services Inc. (GES, Princeton, N.J.), Istar Internet Inc. (Ottawa), Netcom Online Communication Services Inc. (San Jose, Calif.), and Performance Systems International (PSI, Herndon, Va.). Most have configured their Web servers to accommodate audio and many resell Internet voice software and offer customer support for the service. And the majority claim to be upgrading their networks to better handle voice.

Even AT&T, MCI Communications Corp. (Washington, D.C.), and Sprint Corp. (Kansas City, Mo.) have publicly announced support for Internet voice, even though they stand to lose long-distance revenue. Unlike many resellers, the Big 3 aren't asking the Federal Communications Commission (FCC) to regulate Internet telephony. Still, none of them are marketing Internet voice services or reselling the requisite software--yet. Sprint and MCI say plans for an Internet voice strategy are in the works. AT&T will not divulge any details.

The Application Angle.

At the basic level, companies are considering Internet telephony for internal voice traffic. But transmission quality troubles some potential users and providers. "I see Internet telephony as a poor man's long distance. It's something you'd use to talk to your grandmother but not to make a sales call," says Rick Francis, chief technology officer for Netcom, which is conducting Internet voice trials.

Some companies are looking at Internet voice not as an alternative phone service but as a way to enhance their Web sites. For example, McDonald's Corp. (Oak Brook, Ill.) may add an audio icon to its home page. When visitors click on it they'd be connected to an operator. The company hasn't decided whether to implement the technology.

Internet telephony also can be used for real-time or recorded audio broadcasts. For instance, Capital Cities ABC (New York) runs audio feeds over a server on Uunet's network. Every 10 minutes a new audio feed is downloaded for affiliates to retrieve. And Internet voice also can be used to dress up videoconferencing and whiteboard applications.

Voice Boxes

Users can only make phone calls over the Internet if they have the right equipment. At minimum that means a 25-MHz 486 platform, 14.4-kbit/s modem, and Internet access. The PC also must have a microphone, speakers, and sound card--along with client software. A 28.8-kbit/s modem will go a long way to improve voice quality; ISDN or dedicated T1 (1.544 Mbit/s) deliver the best results.

Some of the latest products available on the market include:

There are three methods for making calls: directory services, point-to-point connections, and gateways (see Figure 1). Directory services are the most common. Each software vendor maintains a server containing a directory of IP addresses of gear equipped with Internet voice software. Users log onto the server and view the list that indicates which recipients are online (they need to be online to receive the call). Then the user clicks on the IP address and initiates the call. Some ISPs, like PSI, maintain similar servers.

With a point-to-point connection, users bypass the directory server and simply enter the IP address of the person they're calling. As with directory services, the problem with this approach is that the recipient must be online waiting for the call. This means that the sender may have to first call the recipient over a regular dial-up line before the Internet voice connection can be established.

Gateways also are emerging. Vocaltec Inc. (Northvale, N.J.), which makes the most widely used Internet voice software, has just announced a gateway server for businesses or ISPs. It costs $4,000, including both hardware and software. Here's how it works: Suppose a company has Vocaltec gateways in its main offices in New York and London. A user in New York picks up the phone or clicks on the client software, connects to the New York gateway, and dials the recipient's London number. The call travels over the Internet to the London gateway, which connects the call to the right person--all for the cost of Internet access. If the recipient is in London but not in the office, the gateway initiates a call over the public switched telephone network (PSTN) to the local London number--for the price of Internet access plus a local dial call. It sounds like a good idea, and it's already catching on. International call-back companies like IDT Corp. (Hackensack, N.J.) are even now using gateways to offer bargain-basement international service.

Talk, Talk, Talk

Internet voice makes the most sense for companies with a high volume of international or domestic long-distance calls. "We would save over 50 percent off our long-distance bill with Internet phones," says the EPA's Orndoff, who is conducting trials using software from Intel Corp. (Santa Clara, Calif.) and Vocaltec.

But not everyone comes out a winner. Many large companies have already fought hard at the bargaining table to win contracts for virtual private networks (VPNs) with per-minute rates as low as 6 to 12 cents. For them, the small savings may not be worth the up-front investment in Internet telephony--or the trade-off in quality.

How much a company saves depends on specific circumstances, and separating fact from fiction can be a daunting task. The place to start is by determining if there is an appropriate application for Internet voice. If there is, net managers should set up a quick, basic trial and come up with a detailed cost-analysis:

Doing the math also means factoring in up-front costs like PC upgrades and voice software. And make sure break-even estimates only cover a choosen application, not all the company's voice traffic.

ISPs typically charge dial-up customers $10 for five hours of access, or 3.3 cents a minute. Some companies, like Netcom, charge about $20 a month for unlimited usage. Compare that with the average domestic long-distance call at 22 cents a minute or international calls at $1 or $2 a minute, and savings can add up pretty quickly. Even VPN customers can save significantly if up-front costs are low.

Start-up costs are one of the many factors business customers need to consider. And they need to be considered carefully. For starters, net managers need to assess whether corporate PCs are powerful enough for voice. If not, factor in the cost of new platforms. Then they have to determine if the boxes are equipped for voice communications. If not, add $75 to $300 per PC for microphone, speakers, and sound card--plus another $30 to $50 for client software.

Then add up the amount of money spent on long-distance calls that could be routed instead over the Internet or corporate intranet. It sounds simple, but it's not. Bear in mind that if Internet voice traffic is heavy enough to require another dedicated access line, that cost also must be factored in.

The Quality Question

Voice performance is gauged by measuring delay. Calls on the public switched telephone network usually exhibit a 50- to 70-millisecond delay. That latency increases substantially on the Internet, where it typically ranges from 500 milliseconds to 1.5 seconds (an eternity when it comes to voice traffic). Then again, slowdowns on a corporate intranet (where traffic is transmitted over a single carrier's network) can range from 70 to 120 milliseconds, indicates Jeff Pulver, internet analyst at Pulver.com Inc. (Great Neck, N.Y.) and author of the Internet Telephone Toolkit.

The good news is that delays are generally decreasing, thanks to more effective compression. When Vocaltec released its initial software 18 months ago, Internet delay was at least 500 milliseconds. With the recent release of 4.0, that figure has dropped to 300 milliseconds, claims Elon Ganor, Vocaltec's chairman and chief executive officer.

Understanding the cause of performance problems means understanding the Internet itself (see "The Online Corporation: Choosing the Right Internet Service Provider," November 21, 1995.). The Internet is composed of about 11,000 individual networks, each linked at one or more network access points (NAPs)--where high-capacity routers pass traffic from one net to another. The trouble is, the NAPs also are hot spots when it comes to congestion. To bypass NAP congestion, many large ISPs have established private connections with one another. They rely on the public NAPs for backup and to link to smaller ISPs. That's more reason than ever for net managers to carefully study how ISPs engineer their backbones.

ISPs also can improve quality by optimizing backbone design to reduce the number of stops a call makes at routers or switches. Increasing backbone bandwidth also will boost voice quality.

Further, net managers who want anything remotely resembling hi-fi sound should dispense with dial-up entirely, opting instead for dedicated Internet access. But they'll need enough users to justify the expense. A T1 access line will accommodate 24 to 192 users, depending on bandwidth requirements, and costs between $1,000 and $3,000 a month. A dial-up circuit, in comparison, goes for $20 a month.

Making Reservations

Many performance problems will be addressed by the new service levels made possible by RSVP (resource reservation protocol), a spec from IETF (Internet Engineering Task Force) that's expected to be ratified in about a year. RSVP defines how routing software reserves circuits for a designated transmission. Initially, users will call their ISP and order a circuit between locations with a specified amount of bandwidth. Later, when the software is upgraded, the packets themselves will include flags that indicate the sender is paying for RSVP priority. Either way, the router does the same thing: It defines a path from point A to point B, opens it for the call, and closes the gates behind it so no other traffic can share the line.

Quality aside, ISPs need to develop RSVP service levels for another reason: so they don't go broke. Most corporations don't use all of the capacity on the dedicated access lines they lease from ISPs. As they start to use the spare bandwidth to carry voice, ISPs could be forced to upgrade their backbones to handle additional traffic--without seeing any increase in revenue.

They're not about to let that happen. "We can't let customers blindly saturate our network without recouping costs," says Jordan Becker, vice president for network services at ANS. "We'll start tailoring pricing to reflect the type of traffic being transmitted once we can figure out how to discriminate." RSVP, with its different classes of service, will let service providers do just that. The ISPs will charge less for low-priority transmissions that can tolerate delays. They'll charge more for high-priority transmissions. In the meantime, another way for carriers to avoid taking a hit is to move to usage-based billing, although most carriers have not yet moved to this model.

Pay As You Go?

ISPs still need to determine how they will bill for different levels of service. When the traffic travels over the Internet, it usually passes through multiple networks. An MCI user could request the highest level of service from Seattle to Tampa, Fla. But to get to Tampa, the traffic might travel through networks owned by Compuserve, BBN Planet, and Sprint. "It's more than technology at that point. Who gets paid and how?" says Mark Fedor, director of engineering at PSI. Thus far, there's no answer to that question.

Until a billing mechanism is worked out, net managers shouldn't expect to see service classes on the Internet. Corporate intranets are another matter, however. Because intranet traffic travels over one network, providers have control of the service levels from end to end--and can bill accordingly. Sprint is one of many ISPs that plan to offer service classes based on RSVP within the next 12 to 18 months.

Nearly 75 percent of U.S. companies already have or plan to incorporate intranets, according to Business Research Group (Newton, Mass.). If the access lines, security, and servers are already in place for data applications, the incremental cost to add voice can be low. "If you're running a corporate intranet and you have control of your traffic, why aren't you taking advantage of voice over the Internet?" Pulver asks.

The answer is that long-distance carriers still have some big selling points. "None of the ISPs offer service guarantees," says Sergio Hecker, chairman and chief executive officer of GES. "It's going to be a tough problem to solve." Hecker says it will be difficult for GES or any ISP to guarantee throughput over multiple networks.

Still, network managers could benefit from running some trials while the ISPs and software vendors continue to hammer out the technical issues. Most experts say Internet telephony will be widely used within two years. "Internet voice isn't ready to bet the business on yet, but it will get there," says ANS's Becker. "Now, it's in the trial stage."