GMI spotlights work to be done linking IMS, IPTV

Bringing IMS and IPTV together became a prominent goal when service providers realized they needed the control infrastructure of their video distribution networks to be part of the IMS control infrastructure discussion in order to deliver seamless services to end users, Wegleitner said.

What GMI 2008 showed is that “the IMS core is mature, but interfaces to the extended components need work,” said Naseem Khan, principal member of technical staff at Verizon and a member of the MSF board. “We see significant challenges with roaming, and the policy-management function is much more mature for wireless than for broadband.”

It was possible to test 3GPP services end-to-end but not broadband services such as IPTV because, “We cannot connect to the IMS core,” Khan said. Where the IPTV test case was concerned, “The proof of concept was successful, and we validated registration and configuration mechanisms,” he said. “We also validated the ATIS QoS metrics in the network context.”

GMI showed, however, that standards need to be developed for Mean Opinion Scores (MOS), the common approach to measuring quality of user experience. “Different platforms are using their own algorithms,” Khan said. Because packet loss as low as 0.5% can produce unacceptable video quality, tightening the MOS baseline for video is important.

“The really good news is that IPTV and IMS are mostly interoperable,” Khan stressed. “The interface between the IMS core and the video media server worked well, but the UE [user element] to IMS Core interface is still problematic.”

Under an IMS approach, information about the user, including profiles, is housed in the home subscriber server, but that is not yet defined for IPTV. “We have to define a way to store the service selection function on the HSS,” Khan said. “That’s an industry standards issue.”

It’s important because service providers want to be able to deliver video over multiple platforms, and it will be important to know what UE is involved to know what kind of video should be delivered, Dan O’Callaghan, principal member of technical staff at Verizon and head of the ATIS IIF, explained.