General

The IPTV Testing System

As carriers and ISPs prepare IPTV rollouts, one company is ready to help them test their service before it runs on the network.

by Gerry Blackwell [December 6, 2005]

If you think providing high-speed Internet service is technologically complex and fraught with challenges, just wait until you add voice and then video to your network. That's the message that Crawley, UK-based Spirent plc, a leading network testing company, is sending out to aspiring triple-play service providers.

Spirent recently introduced a new suite of test services targeted specifically at network providers planning to or in the process of adding IPTV to their service mix. The company's IPTV Subscriber Experience Test System assesses the quality of the picture subscribers receive as well as every aspect of supporting services and infrastructure.

A publicly traded corporation headquartered in the UK, Spirent has a legacy that goes back to the 1930s and founder Jack Bowthorpe, whose first company was called Goodliffe Electric Supplies. It became Bowthorpe plc. in 1992 and then became Spirent in 2000.

The company reported first half revenues for 2005 of about $405 million. Its Performance Analysis group, which offers the network testing products and services, contributed about $156 million.

Can you hear me now? Can you see me now?
Putting voice on an IP network is difficult enough to do well, says Spirent director of business management Michale Stoos. Video adds even more complexity and with it an increased chance of service degradation that can drive subscribers away and kill revenues.

"The simple fact is that IP networks were designed to carry data, they're non-real time," Stoos says. "And real time applications like video are very sensitive to things like packet loss, delay, and jitter, which data is not. All of these impairments are the consequences of trying to use a network designed for non-real time data to carry real time applications, stretching it way beyond its natural capability"

But it's not just that video adds technological complexity in the network. Subscribers will also have higher expectations of IPTV than other applications. Most new subscribers to high-speed Internet services come from dial-up services. They're prepared to put up with problems to get the much higher performance. Most new IPTV subscribers, however, will be switching from cable or satellite service. They know how the service is supposed to work and they'll be a lot less tolerant of poor quality and network failure.

"That creates a big challenge for the carrier," Stoos says. "It means their [IPTV] service has to work at least as well as satellite or cable. And it has to work right the first time."

Complicating things is the fact that IPTV technology is still very new. "At this stage, a lot of issues for IPT have to do with the lack of maturity of the technology," says Spirent vice president of IP telephony Bahaa Moukadam. "There is still a lot of evolution to go through in terms of the underlying technology—the transport mechanisms, the encoding schemes, etc. We haven't really reached Version 1.0 yet."

The way to meet these challenges, according to Spirent, is to institute a program of ongoing testing at every stage of service development, starting in the lab and continuing with field testing. And of course it goes without saying that the Spirent products and services are the best available.

Certainly Spirent is a dominant force in the market for such products. Among its acknowledged customers is SBC Communications Inc., currently in the process of developing an IPTV service based on Microsoft technology. "We are engaged with several carriers and equipment manufacturers, providing consulting and products, including SBC in Texas," says Spirent vice president of IP telephony Bahaa Moukadam.

Testing, testing
What do IPTV service providers need to test for? A big part of it is the subscriber experience which includes two main areas. When you enter a channel on the remote control, how long does it take for the channel to change? This is important because one of the claims of IPTV is that it changes channels faster than cable or satellite? And is it the right channel every time? The other part of it is how good is the audio and video quality?

Go to page two: Understanding video packets >