Voice Over the Network is the emerging technology that will allow the voice community, i.e. public telephone customers, to facilitate telephone-like voice communication over the Internet or an intranet. The technology requires 1) a personal computer with a microphone and speaker or 2) a telephone handset that’s connected to the Internet with the proper equipment for conversion.

Voice Over the Network, like many new technologies, has many names; IP Telephony, Voice Over Net just to name a few. It also has a variety of solutions, such as, Voice Over ATM, Voice Over Frame Relay and Voice Over IP.

This paper, when referring to Voice Over the Network will use the acronym VON.

The Internet and The Public Switched Telephone Network.

The Internet is an extremely complex medium that uses routers, switches, hubs and bridges to transport data/voice/video to and from anywhere in the Internet/Intranet community. Over the years, the Internet has evolved to the point where it combines elements of telecommunication, computing, commerce, publishing and other informational services into a revolutionary and new model for global communication.

The Public Switched Telephone Networks (PSTN) for decades have been the primary carriers of voice communication and the providers of leased line service for data networks; however, these carriers are starting to realize that their dominance in the voice arena may be challenged.

In today’s networking, there are several attractive alternatives to the conventional Public Switched Telephone Network. Among the most interesting are the networking technologies based on a different kind of voice transmission called packet voice. Unlike the Public Switched Telephone Network, which is circuit-switched, the Internet is packet-switched; communication on the Internet is accomplished by sending small packets of data back and forth. In addition to the data itself, each packet contains an address to ensure that it is routed to the correct destination. The exact format of these packets is defined by the Internet Protocol (IP). The data, of course, can be just about anything, including encoded, digitized voice.

Because individual packets can take different routes across the Internet and arrive at different times, packet-based voice communication is particularly challenging. Unlike a text message (i.e., e-mail) which can eventually be reconstructed once all the packetized pieces have arrived, real-time voice communication requires timely delivery to avoid significant pauses which would render it virtually unusable, or at least not nearly comparable to the traditional telephone communication.

Architecture Differences between the Internet and PSTN.

The Internet architecture is based on dynamic routing versus the Public Switched Telephone Network, which is based on static switching. The dynamic routing provides a decentralized or distributed environment, whereby the static switching relies on an environment that has centralized Points Of Presents (POPS) in a network. The decentralized architecture of the Internet promotes flexibility, which can result in rapid development of new technologies and new forms of competition. This also creates a paradoxical relationship between the Internet and the Public Switched Telephone Network.

The paradox is that many of the Internet customers connect to the Internet via a modem, which utilizes a traditional phone line and that a majority of the Internet traffic is carried over the Interexchange Carriers lines, such as, AT&T, MCI and Sprint; most Internet applications, such as VON, are likely to be seen as another source of revenue for the traditional telecommunications carriers. Yet, this cannot be, because the voice packets will traverse existing Internet connections, which are not bound by the current Federal Communication Commission (FCC) regulations.

Finally, there exist some obvious cultural differences as a result of the different architectures. The Public Switched Telephone Networks contain "settlements" which charge each other to exchange traffic, while the Internet is, for the most part, void of usage-sensitive charges as they simply do not apply to the Internet’s "peer agreement" statement.

FCC Regulator Issues.

The America’s Carriers Telecommunications Association (ACTA) claims that a petition filed with the FCC (see Appendix A) is for preserving a so-called "level playing field" between traditional long-distance telephone companies and the Internet. There are some who believe the true objective of the petition is to protect a regulatory anomaly allowing arbitrage—technically known as "resale"—from assault by a new technologically advanced form of competition.

Several issues that will have to be addressed by the FCC are:

How to treat Voice Over Net software manufacturers.
How to identify voice packets from data packets.
Who is the carrier for a Voice Over Net phone call?

The software and hardware vendors that provide solutions for Voice Over the Network common response to the above is:

Can you truly classify a software manufacturer as a telecommunications carrier.
That’s an impossible task since there are an infinite number of ways to encode them.
There is no single long distance carrier responsible for a user’s VON call, but instead, many Internet Service Providers (ISP’s), use the "peer agreement".

The Baby Bells, Bell Atlantic in particular, are also trying to get into the long distance communications business by filing a petition with the FCC, in an attempt to take advantage of a little known section of the Telecommunications Act of 1996, that requires the FCC to take steps to speed the development of high speed data services. In its filing, Bell Atlantic stated, " the long distance restrictions impeded its expansion and offering of high speed, packet switched data services, including Internet services to its customers".

Why Voice Over the Network?

The telephone is the most pervasive of all technology instruments, particularly in business. Everyday, businesses make literally thousand of calls, and though the cost of an individual call is often low, the accumulated cost to businesses is significant. For most companies, a portion of that cost is avoidable, as discussed below.

Traditional Public Switched Telephone Networks are a complex tapestry of tariffs and subsidies, often resulting in situations where calling from point A to point B costs a fraction of the rate from point B to point A. Companies have long relied on private, leased-line networks to bypass public telephone charges, but rates applied to leased lines are also high. Many have looked for alternative strategies.

In today’s networking, there are several attractive alternatives both to conventional public telephony and to leased lines. The Virginia Community College System addressed the latter with the implementation of an ATM packet switched IP based backbone network. The Virginia Community College System could further reduce its phone charges by also using the ATM packet switched IP based network for Voice. But like all good things packet voice has a price.

Even where new transport capacity must be added or purchased to support packet voice, the benefits may justify the cost. Public telephone networks often impose distance-based tariffs and added charges to subsidize residential calling. The use of data networks for voice transport can significantly reduce these costs.

A company must be very careful when selecting a VON solution, for instance, some vendors that offer VON to the desktop may require sound cards, microphones, and the like, along with an adapter to link the phone to the PC. Some may require client software that converts voice into IP packets and/or a gateway server that converts voice into IP packets to send over the Internet or to a Private Branch Exchange (PBX) across the Public Telephone System Networks.

There are some vendors that attach the phones to the IP network and others that attach the PBX to the IP network via a router.

The vendors have the equipment and software to provide the VON service, but how will a company know if the purchase of the equipment and software will cut its telephone costs.

There are two variables that must be established for a cost analysis:

Bandwidth voice consumption
Total minutes of voice traffic that will be shipped over the IP network.

Once the variables are established, the cost per minute can be calculated by dividing the equipment and software cost by the total number of minutes, thus establishing a payback time. The payback time would be adjusted according to budget requirements.

How can the Virginia Community College System incorporate a VON within its enterprise network?

The Virginia Community College System, because of its implementation of an ATM network, is in a unique position to take advantage of two out of the three Voice Over Net solutions previously mentioned: Voice Over ATM and Voice Over IP. There are vendors that provide both the hardware and software solution for connecting to an ATM switch and to the PBX (voice over ATM) and there are other vendors that provide only the hardware solution (routers) for connecting to a PBX (voice over IP). The connection allow internal voice traffic to traverse the enterprise IP network, while the external voice traffic would continue to traverse the public phone system for off net voice traffic. An implementation of one of the above solutions would eliminate all long distance phone charges among the System Office and thirty nine campus locations.

How would the Virginia Community College System implement a VON within its enterprise network?

The Virginia Community College System would implement a VON network by: 1) reviewing its existing voice equipment and evaluating its capabilities and operating cost, 2) defining VON objectives, i.e. reduce long distance cost, reduce trunk line cost, etc. 3) select the solution that best fits the needs of the VCCS, 4) define technical guidelines such as voice quality and acceptable delay, 5) perform a capacity planning study, and 6) perform a financial analysis.

How would an individual college incorporate a VON within its campus enterprise network?

If a college has multiple campuses that traverse several exchange carriers or has a need to reduce trunk cost between campuses that employ Centrex units, the college should investigate a VON solution. It should be noted that the VON is not a replacement for the Centrex unit, but will aid in reducing trunk cost.

How would an individual college implement a VON within its campus enterprise network?

Each community college and its campus use the ATM backbone as a means to communicate with other sites in the VCCS enterprise network and to communicate with the Internet. From a network perspective, any connection from the edge device, ATM switch, to the college/campus is viewed as an individual network or intranet. Therefore, the VCCS enterprise network is comprised of 40 intranets including the System Office. Thus, any college with multiple campuses will have several intranets within its college network.

A multiple campus college presents a unique challenge for implementing a Voice Over the Network solution, especially if the campuses consist of several PBX’s and one or more Centrex units.

The steps outlined above for implementing a Voice Over the Network solution for the Virginia Community College System enterprise network would also apply for college implementation, but the configuration and solution would be different.

The Virginia Community College System enterprise network solution move towards Voice Over ATM, while the multiple campus college solution move towards Voice Over IP.

The two basic ATM models used to integrate voice with data are: transport and translate. An example of transport is the simulation of tie lines over ATM using circuit emulation. An example of translate is the interpretation of voice signaling and the creation of SVC’s within ATM.

ATM Transport Model

In the ATM transport model the voice signaling is carried through the network transparently. PVC’s are created for both signaling and voice transport. First, a signaling message is carried transparently over the signaling PVC from end station to end station. Second, coordination between the end system allows the selection of a PVC to carry the voice communication between end stations.

In the ATM transport model the ATM network does not participate in the interpretation of the signaling that takes place between end stations.

ATM Translate Model

In the ATM translate model the ATM network interprets the signaling from both non-ATM and ATM network devices. PVC’s are created between the end stations and the ATM network. A signaling request from an end station causes the ATM network to create a switch virtual circuit (SVC) with the appropriate quality of services (QoS) to the desired end stations.

The ATM transport model is less complex and much easier to implement than the translate model. Yet, the ATM translate model provides more efficient use of bandwidth and the ability to switch calls within the network, which could lead to the elimination of the Tandem PBX and potentially the edge PBX. Also, QoS for connections do not need to be constant as with PVC’s.

Voice Over IP.

The Voice Over IP model compares to the ATM translate model because of its robust signaling, addressing and routing functionality.

Voice Over IP Signaling

Signaling in Voice Over IP has three distinct areas: signaling from the PBX to the router, signaling between routers, and signaling from the router to the PBX. The connections between the PBX and the router appear as a trunk line to the PBX. When the PBX receives a request to seize a trunk line via the router, the PBX forwards the dialed digits to the router in the same manner the digits would be forwarded to a telco switch. The router maps the digits to an IP address and routes across the network. The remote router receives the request and issues a request for a line seizure to the PBX. When the PBX acknowledges the line seizure the router forwards the dialed digits to the PBX, which, in turn, rings the dialed number.

Voice Over IP Addressing

In most organizations the first procedure implemented is the mapping of IP addresses to predefined stations or locations; therefore, it should be a relatively easy task to map a phone number or a portion of a phone number to an IP address for routing across the network.

One of the major strengths of the Internet Protocol is its routing capabilities. With the emergence of sophisticated protocols such as Enhanced Interior Gateway Routing Protocol (EIGRP), it is able to take delay time caused by other routers into consideration when calculating the best path through the network.

Voice Over The Internet, would appear to benefit only large international and/or national corporations because of the savings that could be derived by reducing international and domestic long distance telephone charges. It has; however, a cost-effective solution for any company that makes a significant number of long distance calls within the company.

Voice Over The Internet has been implemented, at some companies, solely to support their Customer Support Call Centers. Customers use a WEB browser to talk with customer support representatives when reporting a problem. Others have implemented Voice Over The Internet to reduce the high fax transmission cost within their companies. And others have implemented Voice Over The Internet to reduce line cost between headquarters and branch offices.

The Virginia Community College System, which is comprised of 23 Community Colleges, their campuses, and the System Office could benefit from the implementation of Voice Over The Internet by reducing the costs of long distance calls and fax transmissions among the colleges/campuses and the System Office. The Virginia Community College Utility agency with its statewide Help Desk function would also reap the benefits of reduced long distance charges.

Both Voice Over ATM and Voice Over IP are two solutions that could be implemented within the Virginia Community College System enterprise; Voice Over ATM for the ATM backbone, and Voice Over IP for the College infrastructure. Voice Over ATM would allow connections to be set up on demand using SVC’s and Voice Over IP would allow those colleges using Centrex to reduce trunk cost between campuses.

Mr. Charles H. Helein, General Counsel for ACTA stated "There is something fundamentally wrong from our members’ perspective, that somebody can talk over the Internet for free. They’re giving away our product".

It should also be noted that Michael Armstrong the CEO of AT&T, announced in the February 2, 1998 issue of INFORMATION WEEK that "One new service, initially aimed at consumers, is a Voice Over IP offering priced at 7.5 cents to 9 cents a minute". This statement by Mr. Armstrong seems to be in contradiction to the desires specified in the March 1996 petition filed by ACTA.