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Critical IP Infrastructure Issues: Navigating VoIP From Fad To Mainstream

By Steve Granik, NeuStar


The move to Internet protocol (IP)-based communications, including voice over IP (VoIP), has accelerated existing pressure on voice revenues for communications service providers. To date, much of the attention has been on the opportunity to generate innovative new services using SIP, presence, and enhanced mobility capabilities as a way to build new revenue streams.

Several important, and often overlooked, infrastructure issues that deserve attention and are critical to the mainstream success of VoIP include:

• Enabling IP-to-IP interoperability while preserving full PSTN interoperability;
• Implementing new provisioning solutions optimized for VoIP services in the face of declining voice margins while continuing to support a parallel PSTN infrastructure; and
• Ensuring VoIP security. These issues must be addressed for VoIP services to become mainstream and realize their revenue-generating potential.

The fast-changing industry landscape further complicates these issues. For example, next-generation service providers like Vonage break the telephony service provider mold; this is only getting more interesting with parties like AOL and Earthlink entering the voice market. These new models compound the already complex problem of seamless migration from, and interoperability between, the circuit switched world and the evolving IP world. Additionally, cable companies are looking to bite off a piece of the VoIP pie, introducing yet another layer of complexity.

If reliable, affordable, high-quality VoIP services are to emerge — and if service providers are to generate revenues as a result — the industry must address these fundamental issues in a comprehensive, impartial manner.

Many Dimensions Of Interoperability
An important fact of life in the communications world is that communications economics rely on the network effect — that is, communications services increase in value exponentially as the number of parties that can be reached increases. Consider that we once lived in a world full of disconnected, incompatible e-mail systems with names like GroupWise, PROFS, cc:Mail, and MCI mail. E-mail only really took off with the explosion of the Internet and SMTP, which assured a sender that an e-mail would reach the intended target.

Today’s PSTN is similar to the current state of e-mail. Dial a number, and you can assume the intended target will be reached, whether a customer of Verizon, Sprint, Cingular, or British Telecom. Now contrast this with VoIP. Each VoIP network is an island, glued together by the PSTN. One reason for this lies with naming and addressing, the often-overlooked linchpin of any network. Names are memorable strings of numbers or words, which consumers use to make phone calls, send e-mail or access Web pages. The PSTN uses telephone numbers for names and the Internet uses domain names. Domain names are used to create Uniform Resource Identifiers (URI) like an e-mail address. Addresses are often lengthy strings of numbers that are used by networks to identify other network elements. Addresses used in the PSTN include SS7 addresses and addresses on the Internet are IP addresses. Networks use names to derive addresses.

The industry has rallied around the IETF ENUM standard, based on DNS, to derive an Internet name from a telephone number. ENUM will help unify the naming and addressing between the PSTN and VoIP networks, and between different VoIP networks.

One challenge around the practical deployment of ENUM for telephony is the notion that it should be implemented as a publicly accessible DNS registry like .biz or .com. First, ENUM duplicated an existing “name space” — the e164 numbering plan — with matching domain names. While seemingly straightforward, this process is actually very complex due to the imperative that there should be a unified authority for both the telephone number and the related ENUM domain. The alternative would be routing chaos in which, depending on what network you are on, you could reach many different people with the same address. This problem is especially tricky in places where number portability exists, where tens of thousands of telephone numbers change service providers everyday. How could a publicly accessible ENUM registry keep track of who has authority over the telephone number?

Second, putting carrier information in a public DNS database creates privacy and security risks. While most groups that are planning the deployment of ENUM are trying to avoid these problems, there are some difficult technical issues to resolve as well as complex policy issues from in country and international regulators. To work around these issues, carriers and enterprises are developing “private” databases using ENUM technology for routing between IP endpoints. Methods of interoperability between these private ENUM environments and public ENUM, when it comes to pass, will be important.

It is also worth pointing out that the PSTN and Internet have evolved using different models of inter-party compensation. Business model interoperability becomes even more complex when one considers the economic dependence of many rural carriers on compensation models that include payment for termination. These issues have yet to be adequately discussed, and the dialogue will need leadership with an eye to the greater good from all segments of the industry.

The Provisioning Process
As previously mentioned, next-generation VoIP service providers are challenging the existing provisioning processes associated with number acquisition, management and portability. To date, these newer players have managed these traditional PSTN processes through wholesale relationships with CLECs, who in turn typically rely on manual and, in some cases, semi-automated systems to interact with ILECs.

Presently, customer order requests — for initial service activation, porting in, and transferring in phone numbers — require providers to submit orders manually, via e-mail or fax, to CLECs. If the request is for a ported-in telephone number, the CLECs must interface with other carriers to complete the process, which can be cumbersome and time-consuming.

For VoIP service providers, the resulting delay in service activation and lack of visibility into the process can result in errors, dissatisfied customers, missed revenue opportunities, and an increased risk for customer churn or deactivation. To enable these new business models to scale, this manual process needs to change.
Fortunately, the industry has recently made progress towards enabling full flow-through provisioning; all the way out to the VoIP service providers’ customer care representatives. Improvements such as these will help streamline customer acquisition; increase customer satisfaction, and accelerate revenue realization.

Service providers invest precious capital in software, hardware, and personnel for new VoIP equipment and support systems, and the result can be an unsustainable jump in OPEX and CAPEX in the face of intense price pressure on basic voice services. For many, this happens while they must still support an existing parallel PSTN infrastructure that will not work for VoIP. In addition, these service providers often discover that their initial investments do not match emerging market imperatives. For example, a service profile that is designed for simple consumer voice services will require enormous additional investment to also support business multimedia. ROI can be an unattainable goal — in an unforgiving industry environment. This situation begs for new approaches. One alternative is starting to gain traction with immediate bottom-line results: a clearinghouse service that enables new service creation without requiring expensive infrastructure investments and their related timelines.

VoIP And Security
Security is the soft underbelly of IP networks. While there are many reasons for this, one prominent security threat is the ease by which people can assume false personas and impersonate others in IP environments. VoIP services are not immune, and several scams have been reported recently in which “bad guys” fraudulently “spoof” others’ identities in SIP to gain access to networks, send SPAM, commit identity theft, and distribute malware.

SIP identity standards have been released to deal with these transgressions. It is imperative that software and hardware vendors implement support for SIP Identity sooner rather than later. VoIP can ill afford to develop a reputation in the market as the “voice cousin” of e-mail when it comes to security and privacy. It will require a concerted industry effort toward broad adoption of SIP Identity standards to avoid this fate, and solutions will likely require new services for independent “real-time” identity verification.

Also, it is important to realize the trust models for VoIP, even in a carrier context, are fundamentally different than those of the PSTN, because in VoIP, many more parties are true peers. The most obvious example of this is an enterprise with an IP-PBX. At first blush, it appears that a specialty firewall/network address translation device, like a session border controller, is adequate for securing the carrier’s network (and for that matter, the enterprise’s network). But that assumes the problem lies in trusting the network directly adjacent to yours. Closer examination shows this to be a false sense of security, since there is really no way to know the true source origins of traffic entering a carrier’s network. So, while border elements form part of the solution, they are by themselves, inadequate. SIP Identity remains critical. This is the reality of VoIP.

Next Steps
VoIP is clearly coming to the mainstream. It promises creative ways to bring new personalized services to customers both businesses and consumers. While slick demonstrations of new technology are always exciting, mainstream adoption will require complex infrastructure processes to be efficient, both inside of and between service providers.

Resolving the problems of inter-party interaction in the PSTN has proven a challenging and long process, with much inefficiency still rampant. It is in the best interest of all parties to avoid using that process as a roadmap for resolving VoIP interoperability, security, and provisioning efficiencies. This challenge that will take time, but it can be addressed and solved through the collective work of the industry at large including service providers, vendors, standards bodies, and the regulatory community. IT

Steve Granek is vice president, Advance Services at NeuStar. For more information, please visit the company online at

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