The DSL Forum is helping IPTV providers get a better view into user quality of experience

The DSL Forum might not seem like the obvious organization to tackle IPTV standards, but based on its work delivering end-to-end visibility into broadband networks via its TR-069 standard, the global group is now firmly focused on IPTV quality of experience as well.

The result has been a variety of efforts that look at what happens inside the digital home, as well as in the access network and at the network operations level.

“If you look at the work we have done in this space, we started with TR-126 [Triple Play Quality of Experience Requirements], which looked at triple-play requirements from not just a quality of service standpoint, but a quality of experience of the end user — whether it was for gaming, IPTV, voice or surfing the Web,” said Gavin Young, technical committee chair for the DSL Forum. “Once we had all those requirements, we looked at what does that mean for the end-to-end delivery network. The ground-breaking work had been done in individual services. As service providers moved toward bundled service, we wanted to provide a one-stop shop.”

That encompassing document, now delivered, was picked up by ATIS in its IPTV Interoperability Forum and the ITU, Young said.

More recently, the DSL Forum developed WT-135, which is a set-top box (STB) data model built on the TR-069 work, said Heather Kirksey, chair of the DSL Forum's home group.

“We did a lot of work around specifically getting information about quality of experience from the user,” Kirksey said, “and then putting those in the data model so you can extract them via TR-069 and do analysis on what quality looks like at the set-top box. It includes all of those down-and-dirty concepts — jitter, buffer overruns, lost frames — that can give you insight into picture quality and into what the user sees.”

Because picture quality issues are transient, the idea is to do performance monitoring that lets service providers get an ongoing picture of what users are experiencing so they can be proactive when addressing problems, Kirksey said.

At this point, there is widespread use of residential gateways that support TR-069 but not of TR-069-based STBs. “It is lagging; they aren't deployed as much as residential gateways,” Kirksey said.

That is likely to change, however, especially in Europe, where IPTV is more widely deployed. European carriers “led us in a lot of the requirements work,” Kirksey said.

By maintaining an end-to-end view that provides analysis in addition to error rates and other basic information, the service provider can more rapidly pinpoint problems, Young said. “With TR-069 and WT-135, you can see to the DSL router and to the set-top box, and you can determine if the problem is in the home or on the copper. One day that might be embedded in the digital TV,” he said.

Because of video competition, IPTV providers know they have one chance to get the service right. “Some customers might not even call and complain, they might just churn,” Kirksey said. “This way you can prevent churn even for those people who don't call up.”

The DSL Forum also is developing requirements for copper bonding, which many IPTV players are looking at to handle delivery of high-definition signals, and it has developed agnostic versions of standards that can apply to Gigabit passive optical network technology and even to wireless access, Young said.