VoIP Test and Monitoring Moves to the Next Level

By Paula Bernier

Going forward, VoIP will no longer be a singular service. Rather, it will be just another component of various communications solutions that might be running over a converged network, which could be based on the IMS architecture. At least that's where many folks believe all this is heading.

That said, how will network operators – be they enterprises or service providers – ensure the quality of finicky old voice on these new converged, IP-based, FMC-enabled, possibly IMS-architected networks? And how could service providers take VoIP testing and monitoring a step further to not only ensure high-quality voice, but actually to create new revenues? Some of the leading VoIP test and monitoring companies recently spoke with NGN to explain.

A Holistic View
"Some of the things that we are seeing currently is that the carriers are looking not only at monitoring for SLAs, but are inherently concerned about helping to diagnose troublesome network anomalies," says Mark Stacy, CEO and CTO of Touchstone Technologies Inc. "These problems can be difficult to find at best, and are extremely costly and time-consuming to cure as well. It is because of this 'next-generation' of monitoring and diagnostics capabilities that Touchstone was recently awarded a contract for monitoring the world's largest tier 1 carrier's business VoIP network initiative."

Whether you're talking about service provider networks or private networks, the objective is to ensure the end user has a good experience, says Gordon Eddy, director of product management and marketing for the network assurance business unit at Empirix, which provides testing and performance management solutions.

That creates a requirement for end-to-end testing and monitoring, adds Tim Moynihan, vice president of marketing for the contact center business unit at Empirix. In the enterprise space, says Moynihan, Empirix offers tools that allow customers to do pre-deployment testing as well as ongoing monitoring and analysis. Empirix also offers an outsourced testing service in which Empirix comes in and does the job for you. In any case, Empirix has various solutions that can evaluate calls whether they come in as TDM or IP traffic, measure latency and other parameters of a call, do load testing before or during deployment, and identify where congestion and other potentially service-affecting issues are occurring in the network, he says. Just this summer Empirix came out with the first product that takes it beyond voice testing, says Bob Hockman, director of product marketing for the network assurance business unit at Empirix. The Hammer Edge allows enterprise network operators to test other services in conjunction with their voice services, he says.

Eddy adds that Empirix also offers the Hammer SIP Trunk Tester, a portable field tool to verify SIP trunks are configured to deliver high VoIP quality prior to turnup.

In the same product family is the Hammer XMS, a carrier-class solution designed to monitor complex IP network and services environments.

Hammer XMS helps service providers like Verscom Managed Services ensure the reliability and quality of next-generation services, and optimize troubleshooting efficiency. Verscom's Managed Wholesale Voice Interconnect platform hosts a large number of operators' outsourced wholesale applications, handling more than 1.5 billion minutes per year over 300 different networks worldwide. Versacom says it was challenged services offerings, which includes "hosted or partitioned" retail solutions such as calling cards, broadband telephony and MVNO, but the XMS helps it do the job. "Hammer XMS diagnostics and service-desk's work-flow oriented design paradigm gave us and our customers all the appropriate information at our fingertips, which resulted in a significant and sustainable competitive advantage," says Gurkan Ozturk, vice president of global sales and marketing at Verscom Managed Services. "With Hammer XMS, we have reduced the service desk and engineering time required for trouble resolution by 25 percent. In addition, we are now able to pinpoint our customers' hosted network/application problems in a reasonably short time frame, which were sometimes left undiscovered due to the system's inability to recreate problem scenarios caused by the very nature of shared/multi-tenant infrastructure.

"To pioneer the world's first true fixed/mobile convergence managed services eco-system, we're now heavily investing in R&D for MVNO enabler applications on our platform," adds Ozturk. "Essential to our success in the enhanced MVNO markets, is the interconnection to 3G+ mobile networks, which will eventually be standardized around IMS. Thus, Empirix's leadership in IMS was also a critical factor in choosing the company as we plan to transition our service infrastructure to IMS over the course of the next one to two years."

New Marketing Opportunities
With the advent of next-generation wireless networks, the rise of the femtocell and the launch of location-based services, carriers will need to "statefully understand what's happening during the customer session," says Will Brouwer, senior product manager for the assurance product line within Agilent Technologies' network solutions division. When you look at the IMS architecture, which allows for the convergence of wireline and wireless networks, service providers can move up the value chain into data mining applications, he continues. For example, say a subscriber is using his iPhone to look up a restaurant application, says Brouwer. The restaurant site might have a phone number and the application might include an autodial capability. So, whatever the application, the service provider could capture who's calling, where they're dialing to and possibly other relevant information, he says. The service provider could in turn use that data to generate reports and provide that information to a third party such as a pizza parlor to gauge the success of an online coupon campaign, for example, Brouwer explains.

As femtocells move into the mainstream, he continues, that adds a whole new twist to this opportunity. Say a subscriber is out in the world using her phone on a GSM network. The GSM operator could enable a pizza parlor to send via the wireless network a coupon for a slice. But once that user returns home, the femtocell could alert the GSM operator of her new location, and the pizza parlor could instead offer her a coupon involving the purchase of multiple pizzas, which she could now potentially share with her family at home.

This is a great example, of course. But does it have real potential, or is it simply pie in the sky? Brouwer says a service provider in Canada is already asking its suppliers to help it support this kind of application. "AT&T as well has these kinds of application aspirations," he adds.

To help support that, Agilent offers solutions including a QoS manager that leverages the company's KPI engine to enable service providers to troubleshoot and monitor the entire sessions of subscriber calls. It can track what IP address or phone number a call is coming from, over what network it's being carried, and the location of the subscriber. It also can report on the call state and quality at multiple intervals during that call.

The End
VoIP is a mature market for carriers, so when carriers move to IMS they want to make sure QoS is really available on IMS, says Tony Vo, product manager for Spirent's Abacus product group, which focuses primarily on voice test related to PSTN-IP interoperability. So they want to simulate as closely as possible SIP and other traffic on the IP network, he says.

But there are a wide variety of different implementations of SIP by endpoint providers, he says, so service providers need test gear that can simulate all those different iterations. Mihai Puchiu, VoIP product manager at VoIP test system supplier Ixia, adds that after getting a ton of press initially, some were talking about the potential death of IMS two years ago. Now that IMS has come back into favor, he says, there's a need to test the IMS core, which involves emulating endpoints such as SIP phones as well as other elements within or attached to the network. Additionally, notes Puchiu, there's now a need to test not just basic calls, but applications that contain voice.

"VoIP protocols and technology may be well understood, but there are a host of potential problems when a high number of calls are mixed with large volumes of data and video traffic," adds Anupam Sahai, vice president of marketing at Ixia. "We developed our Acceleron-XP, VQM modules and IxLoad test application to emulate city-scale communities of real-world users – allowing our customers to discover and solve their device and network problems before their customers do."

Ixia's IxLoad Voice, which the company says matches the capacity of modern media gateways with 1 million SIP- and RTP-based endpoints per chassis, tests such VoIP components as IP-based PBXs, softswitches, call managers, session border controllers, and media gateways, using scenarios involving multiple voice protocols, complex calling sequences, and triple-play mixes of voice, video and data traffic. The product's subscriber modeling emulates user communities that vary in service usage and timing, which Ixia says yields performance results that accurately predict live-network capacity – allowing service providers to provision their networks more accurately.

Specifically, the IxLoad Voice emulates and tests security and network infrastructure protocols, including IPSec, PPP, DHCP and multiple forms of authentication. Voice call security is supported by SIP/TLS and SRTP. And the company's VQM support module evaluates in real time the end user's quality of experience, such as PESQ scores, for 300 simultaneous calls.

Deep Dive
Psytechnics, which began life as a BT Labs research project on how to interpret IP voice and video signals to manage service levels, was initially focused on licensing algorithms to test equipment vendors for PESQ, says Joe Frost, vice president of marketing. But in the past few years, he says, Psytechnics has been selling a voice and video performance management solution, called the Experience Manager, to large enterprises (mostly in the financial vertical) and service providers including AT&T, BT, IBM Global Services and KPN.

Frost says existing network management tools don't have a view of call quality because all they look at is network statistics, service statistics, device statistics and such quality of service parameters as packet loss, packet latency and packet jitter. They use mathematical models to generate an IP MOS score, and they indicate that's a measurement of voice quality, he continues. But the MOS score doesn't take into consideration such factors as whether there may be distortion on the line, he adds.

That's why Psytechnics instead looks at the voice stream – and inside the packet at the waveform – as opposed to the circuit, backbone connection or trunk, Frost explains. With that approach the Psytechnics solution can help identify a wide variety of problems ranging from the cause of a hum on a call to the volume level being set too high on a user phone, he says. As a result, it can help service providers save money by avoiding truck rolls, and otherwise preempt service-affecting issues. Frost says that although Psytechnics has been selling its solution for about four years, it has added a million business end users just in the past 12 to 18 months.

He adds that in the last six months enterprises have become more serious about outsourcing their networks to service providers and, as result, more service providers are looking for predeployment test solutions to ensure adequate bandwidth is available for VoIP. However, he continues, while those predeployment tools are important, once VoIP solutions are up and running there are frequently reports of problems such as excessive echo. The reason that happens is because VoIP is a real-time application, not a bursty application like CRM that can tolerate a bit of delay, he says. That means services providers need to ensure that whatever the enterprise outsourced solution – be it a VoIP call center or whatever, it is monitored and analyzed on an ongoing basis to ensure the highest quality of end user experience.