January 1999

Riding The IP Telephony Rocket

BY MICHAEL J. SARGENT

For network managers who witnessed John Glenn's first and second historic missions into space, there are some valuable lessons to be learned. While managing enterprise networks "ain't rocket science" (as they say), anyone implementing IP telephony in a corporate network within the last few years has witnessed a rapid improvement in technologies that the veteran astronaut could appreciate.

Anyone attempting to implement IP telephony in a corporate network environment just a few years ago faced anxieties similar to those faced by members of the Friendship 7 mission. Both grappled with unproven technology. Both subscribed to "because it's there" mission directives. But ultimately, the pioneering efforts of both led to significant advances in global communications and new opportunities for business.

At the same time, anyone looking at IP telephony for a corporate network environment today can find promise in John Glenn's second trip into space. There is no doubt that, despite his age, Glenn found his ride aboard Discovery significantly smoother than his first flight 35 years earlier, and there was certainly more substance to Glenn's second mission. All hype aside, the STS-95 Discovery mission included the launch of yet another communications satellite: the Spartan. In other words, the mission's purpose was not just about PR - it was also about payload.

One real benefit from these pioneering efforts - both in space flight and in IP telephony - is that we get to learn from them without assuming the same risk. With that in mind, here's a look at the actions you'll want to take to guarantee a safe liftoff for your enterprise Voice over IP (VoIP) applications.

TEN STEPS TO A PERFECT LAUNCH
Create a launch team that includes both telecom and MIS departments The first step in carrying voice and data across the same network is to get your voice and data teams talking. These two technology teams have complementary but often different needs and strategies, so it is critical that they work hand in hand on this effort. Both departments need to agree that they are leveraging this new technology to reduce communication costs and improve productivity.

Understand the "flight path" of your data communications
Can your current data network handle the additional bandwidth demands of real-time voice and fax? A typical VoIP call consumes approximately 10-20 Kbps, depending on the voice encoding (vocoder) algorithm. Fax over IP calls consume approximately 6-16 Kbps, depending on the amount of data, fax machine speed, and resolution. You should understand your voice/fax traffic patterns and, in consultation with your ITSP and MIS department, ensure that you have the capacity to handle both voice and data, plus at least 50% extra capacity. Then plan for growth. Most of your growth will come from your data communications, and remember that traditional telecom network traffic (in minutes) grows at about 3% per employee per year.

Decide on an IP telephony gateway
The gateway provides the interface between the telephony users and the data network. It comes in various sizes to fit different applications, and you should consult with the provider of this technology regarding the number of voice access ports (typically between 4 and 24) you will need. Ports connect the gateway to your PBX/key system, and your technology provider should ensure that this connection is seamless and will handle the voice/fax traffic needs of your company.

Manage your bandwidth
Fax traffic is fairly tolerant of transmission delays (called latency) of around one second, and it can withstand some packet loss (data packets are discarded due to insufficient network bandwidth). Voice traffic is very intolerant of latency (delays in excess of 250 milliseconds one way make the call start to sound like a satellite call) and packet loss (you should ensure you have less than 5% network packet loss).

There are technologies that can help manage your bandwidth for improved Quality of Service (QoS). One such technology is Resource Reservation Protocol (RSVP). This protocol helps prioritize important data (like voice/fax) over data that is not time critical. Another technology is known as "Gatekeeper" technology. This is a software application that can manage your voice/fax traffic over a data network by controlling the number of calls that can occur at any given time during the day.

Examine existing long-distance contracts
Diverting minutes from your long-distance carrier could mean paying more for service, depending on the terms of your contract. You want to make sure that you're not cheating yourself here - look at renegotiating your contract, or determine up front how much traffic you want to divert to your Wide Area Network (WAN) to get the best deal.

Don't forget fax
As much as 30-40% of your telecom bill may be going toward fax transmissions - an expense that could be greatly reduced by routing faxes across your WAN. Make sure you choose an IP telephony gateway that supports both voice and fax over IP, preferably at transmission speeds of at least 14,400 bps.

Keep it simple for your users
Making voice/fax calls over IP on your PBX/key system should be transparent - people are not likely to use it otherwise. Ideally, your PBX/key system least cost routing function will take care of that transparency for you and route calls across your IP network based on parameters you set up. Calls not completed over IP will overflow to the normal public telephone network. If you don't have least cost routing capability, users should be able to select either the public network by dialing "9," for instance, or your IP network by dialing "8."

Measure the performance of your IP voice/data network regularly
Voice quality and reliability are your two parameters. To quantify both, you need to measure packet delay, packet loss, network downtime, and customer or employee satisfaction for IP telephony network elements. Identify when voice quality and reliability are at acceptable levels and use these measurables as a benchmark to help maintain optimum performance. Your ITSP should help you measure and track these parameters.

Innovate and be creative
Cost reduction is a driving factor for IP telephony across the corporate WAN today. However, there are also compelling applications that can strengthen your enterprise in terms of customer satisfaction and greater efficiency. A touch-to-talk Web site could streamline your customer interface and add dollars to your bottom line. Traveling or telecommuting employees can be much more productive and work cost-effectively if their multimedia laptops are turned into virtual extensions of the corporate PBX/key system. Get creative - there will be terrific applications coming.

Understand your payback
Examine your company's calling patterns. If you have high traffic to other company locations, particularly if those locations are international, your investment could pay for itself in 18 months or less. Don't overlook the cost savings from greater efficiency and increased customer satisfaction. You should consider all of these factors in determining your return on investment (ROI). Work with your "launch team" to measure and get consensus on this ROI. Together, you can get the biggest bang for your IP telephony buck.

Michael J. Sargent is vice president of marketing for Inter-Tel, Inc. Inter-Tel is a leader in the IP telephony industry, providing solutions for carriers and corporations. For additional information, visit the company's Web site at www.inter-tel.com.