February 1998

BY JIM UDALL

It’s difficult for an industry that doubles its customer base every three months to not make a lot of noise. One of the hot areas in the Internet today is the delivery of real-time multimedia data. Leading this multimedia charge is voice over IP — a technology that barely existed three years ago, but which now has literally dozens of vendors trying to cash in with products and services using this new paradigm. An industry that generated effectively zero revenue in 1992 will generate $500 million by year-end. The lure is always the same, namely free voice calls anywhere in the world. What exactly are these vendors offering and why should you pay attention?

MARKET SEGMENTS
There are two market segments in which PSTN-to-IP gateways are enjoying some success.

ISP As Telco
The first of these is the emergence of Internet Service Providers (ISPs) as telephone service providers. In the rush to exploit the growth of the Internet, these ISPs are trying desperately to offer value-added services to their customers. Voice over IP (VoIP) is an appealing prospect. Despite the fact that telcos around the world are lobbying vigorously to prevent the growth of this industry, the trend is clear. Telcos certainly have the capability to impede the growth of this market, but in the end it is unlikely they will succeed.

Private Network Domains
The other segment being served by the VoIP industry is the private network domain: In this case, enterprises with a reputation for reliability and consistency that the data communications industry can only dream about. Who would seriously surrender their desktop telephone for a PC that is obsolete as soon as it comes out of the box and has never been known to stay up and running for more than 24 hours at a stretch? Compared to the telecom world, standards on data networks are a cruel hoax. The stunning array of non-compatible acronyms coming out of the data communications world make us yearn for the simplicity and universality of tip and ring.

However, if we make the assumption that the first data networks will begin to approach telephone networks in terms of reliability, and that packetswitched voice has the capability to deliver dramatically decreased communication costs, then no telecommunications professional can afford to miss following this technology closely. If this same technology can go beyond simply reducing costs, and deliver new, valueadded services that remain difficult or elusive with traditional circuitswitch technology, it becomes imperative that these same telecommunications professionals get involved early in order to influence the technology’s direction.

The onus is on the vendors of PSTN-to IP gateways to integrate and interoperate seamlessly with the current voice infrastructure, and it is the telecommunication professional’s responsibility to demand this from vendors. The level of service must be at least as good as what the current circuit-switched technology is offering today. Users must not be forced to give up their desktop phones. PSTN-toIP gateways must be transparent to both the user and the administrator and these gateways must provide traffic information that will integrate into the existing tariffing and billing mechanisms. The features we currently enjoy from either Centrex or a PBX must also be available on this new communications platform.

DEVELOPMENTS & TRENDS
Two things have occurred over the past three years to change Internet telephony.

Market Opportunity
The first was a realization that as long as Internet telephony was restricted to IP networks, the potential market size would be quite small. In spite of the exponential growth of the Internet, the number of locations with Internet access and the technical expertise required to use the equipment, Internet telephony was at best a niche market. Consequently, vendors scrambled to provide gateway access to bridge between the PSTN and the IP network. Clearly, the opportunity for success is orders of magnitude greater when one considers the pervasiveness of telephone sets.

Standards
The second major development that has affected VoIP has been the definition and recognition of H.323 as a standard for multimedia communication over an IP network. As vendors in the classic computing domain began to offer H.323 compliant desktop clients (with Microsoft’s NetMeeting being the dominant entry), PSTN-to-IP gateway vendors began to provide H.323 capabilities to these gateways. Not only could regular PSTN phone users now have access to (presumably) inexpensive or free longdistance services via VoIP, but some four million NetMeeting users could now use their PCs to place calls back out to the switched telephone network. This is roughly where things stood at the end of 1997.

ISSUES
In spite of the fact that H.323 is a protocol designed for multimedia communication over an IP network, a major use of it has been to allow voiceonly devices to communicate over that same network.

Adoption
Until the adoption of this standard by PSTN-to-IP gateway vendors, potential telecommunication customers had been at the mercy of a single supplier. The prospect of deploying a worldwide network of PSTN-to-IP gateways, linked together by an IP network, justifiably frightens even the most daring of telecommunication managers, when a single vendor must supply all these gateways. H.323 is the standard that now allows this technology to be considered on a large scale. As a telecommunication professional, the entry level for consideration of these gateways in your voice network is H.323 compliance.

Scalability
Another issue that must be addressed is scalability. Current PSTN-to-IP gateway technology allows a few hundred concurrent calls at best (and this is pushing today’s technology to the limit). A gateway must be able to handle the current and future needs of your voice network. Alternatively, multiple gateways may have the capability to operate as a single logical cluster. Or, perhaps there is a requirement for small gateways in some locations and larger gateways in others. Does the vendor offer cost-effective gateways for all these situations? In the case of services provided by ISPs, PSTN-to-IP gateways will almost certainly exist in many different countries. Even the enterprise solution will probably involve different geographic regions and consequently, different local carrier connections. Does the vendor offer a suite of suitable PSTN network interfaces to service your current and future sites? Many current vendors tend to focus on the North American market and offer T1 or analog connectivity, yet do not have certified solutions for the rest of the world. Do not assume that a particular type of PSTN network interface is available from a gateway vendor simply because it is commonly deployed in your geographic region.

Reliability
The third issue is reliability. Users have a very low tolerance for loss of voice communication services. How do the PSTN-to-IP gateway vendors provide this high degree of reliability? Are their platforms fault-tolerant? Is their software fault-tolerant? Do they support redundancy and alternate path routing? What about upgrades — both hardware and software? Do they support hot card insertion? Busy out capabilities? Realtime software updates? Many of these features, which are the norm in the telecommunications world, are foreign and exceptional to most of the vendors of this type of equipment today.

Billing & Tariffing
Another important issue to a telecommunications manager is billing and tariffing. Whether it be an enterprise solution or a consortium of independent resellers, calls must be tracked and billed. Tariffing, billing, and revenue sharing among service providers have become a hodge-podge of piece-meal software packages glued together by independent providers. It is unlikely that you will find a terrific solution to this problem from a PSTN-to-IP gateway vendor, that will seamlessly integrate with your own existing tracking and billing structure.

Manageability
A final issue of concern is manageability. Clearly the point of PSTN-to-IP gateways is to interconnect geographic domains across large distances. The corollary is of course that VoIP has equipment spread across vast geographic distances. Maintenance costs to manage these devices and the associated hardware will become quite high without a lot of attention being paid to network management. The accepted standard for managing devices in this domain is SNMP (Simple Network Management Protocol). As a baseline, any PSTN-to-IP gateway must be SNMP manageable. However, SNMP is simply a language of maintenance. It doesn’t define the extent to which devices speak this language. As an analogy, my claim to speaking Japanese may enable me to order a meal at a restaurant in Tokyo, but is probably not enough for me to teach a university course in nuclear physics in the same city.

Though devices may claim SNMP manageability, that may simply mean the device can be viewed from an SNMP management console and nothing more. Robust management capabilities, complete with configuration management, alarms, and traps, is a mandatory feature in deploying PSTN-to-IP gateways.

Value Adds & Future Proofing
Finally, there is the issue of value added services and futureproofing. Though no PSTN-to-IP gateways today offer integration to PBXs and central offices, this requirement will arise very quickly. What are the vendor’s plans for implementing common signaling schemes such as SS7 and QSIG? How can you extend your Centrex or PBX features through these PSTN-to-IP gateways? Can they provide call control features of their own? People talk about using the Web to browse virtual stores and at the click of the mouse, initiate a call to a real operator. Though technically possible to affect the voice connection, what good is that if there is no call center application at the back end to receive the call? Does the vendor provide call center applications? Do they provide APIs to allow third-party call center applications? Do they interoperate with your existing call center operation already running on your PBX? These are very important questions for which PSTN-to-IP gateway vendors must have specific and clear responses.

All this brings us back to our initial assumption — namely that IP is an appropriate protocol to deliver realtime voice traffic. Undoubtedly there are skeptics today — and deservedly so. IP does not intrinsically support real-time traffic, however there is a great deal of work going on in this area. The pressure is very intense and a number of conjoined solutions will ultimately deliver this capability. From a private network perspective, some of these network performance issues are much more contained and manageable. However the Internet as a transmission medium continues to offer significant challenges. Nonetheless, remember this technology is less than five years old. IP will evolve and real-time data will be realized. It’s simply a matter of time.

CONCLUSIONS
Voice over IP is enjoying a great deal of market enthusiasm. However, it is still early in the technological lifecycle. Today’s users are the early adopters. Nevertheless, this will change quickly as the technology gains wider acceptance. Telecommunications professionals must get involved at this early phase in order to influence the proper evolution of the technology. These professionals should demand the following characteristics.

• High reliability: The infrastructure must rapidly approach the reliability of voice networks. Downtime will not be tolerated — regardless of the reason.
• High-quality service: CBquality voice will be unacceptable. Toll quality or near-toll quality is the only option. Low-bandwidth compression technologies will find niche markets, but will never be a serious threat to the current voice network.
• Rich suite of voice features: Call features such as DNIS, ANI, multiple call models, hunt groups, and ring groups are a necessary part of this technology in order to develop value-added desktop or call center applications.
• Interoperability: Interoperability among disparate PSTN-to-IP gateway vendors must be demanded. H.323 is the currently accepted standard for achieving this.
• Seamless interoperability with the PSTN: This interoperability exists at many levels. At the desktop, users must feel comfortable and unaware of the underlying fabric. Current PSTN service providers must be able to manage and service the packetized telephone network in the manner to which they are accustomed. Billing and traffic management must be consistent with the PSTN. Packetized telephony systems must tightly couple with CPE devices via standards like QSIG and with local exchange equipment with standards like SS7.
• Extremely scalable architectures: It will be a requirement not only to deploy a full range of systems from very small to very large, but also to allow these systems to interoperate with each other. Gateways must have the appropriate PSTN interfaces available to provide connections cost effectively in many countries.
• Robust network management: By definition, these products are almost invariably placed in a wide-area network infrastructure. As such, manageability is crucial. Lack of management capabilities will quickly manifest itself as increased support costs.

In summary, real-time voice over IP is quickly becoming one of the hottest commodities in the telecommunications industry. Voice over IP will continue to evolve as new players like Internet Telephony Service Providers (ITSPs) join the traditional ISPs and carriers. The transformations and improvements in reliability, service, features, interoperability, scalable architectures, and network management, outlined above, will be necessary to meet the demands of the VoIP infrastructure. With this in mind, voice over IP is positioned to be a multimillion market by the turn of the century. Jim Udall is vice president of technology at Vienna Systems Corporation.

Vienna Systems, a Newbridge Networks affiliate, is a privately held company based in Kanata, Ontario that designs and manufactures server-based hardware and software products to handle voice, data, and video calls across IP networks, both corporate (intranet) and public (Internet). For more information, visit the company’s Web site at www.viennasys.com

API - Application Programming Interface. A programming interface that allows the development of software that employs the capabilities of other software.

CO - Central Office. In the telecommunications industry, a reference to the termination equipment kept on the carrier’s site that among other things, terminates telephone lines originating at the customer premises.

CPE - Customer Premises Equipment. In the telecommunications domain, refers to equipment that resides physically at the customer’s site.

H.323 - A proposed standard for multimedia conferencing over an IP network.

IP - Internet Protocol. A network and data link layer protocol which is among other things, the foundation protocol for all Internet traffic.

PBX - Private Branch Exchange. Equipment that typically provides companies with local (internal) phone service as well as (usually shared) access to the public switched telephone network.

PSTN - Public Switched Telephone Network.

QSIG - Originally developed in the late ’80s, as a protocol to link ISDN PBXs in a private telecommunications network, has since evolved and found many other important applications. The most important of these currently are:

• Multi-Vendor ISDN PBXbased private networks, including:
• Virtual Private Networks
• Broadband Private Networks
• TransEuropean Trunked Radio (TETRA)

SNMP - Simple Network Management Protocol. A standard accepted in the data communications industry as a method by which devices and software can be managed over a network protocol.