By Carol Wilson
May 7, 2007 12:00 PM
The two major technology initiatives of telecom service providers-deploying IP multimedia subsystem architecture for fixed/mobile convergence and offering video services using IPTV-seem to be on a collision course.
At some magical future date IPTV will become just another IP application in a converged multimedia infrastructure where services are on-demand, provisioning and billing are automated, and all network functions are carved into reusable pieces for easy packaging.
In the decidedly real-world present, however, IPTV is being deployed in ways that lean more toward the Web services realm than the IMS world, while IMS is being used by service providers primarily for voice and wireless/wireline convergence. Don't expect that to change real soon.
“I'm not convinced that IPTV platforms in general are at a sufficiently mature state to start looking at the network integration for other services,” said Richard Griffiths, director of technology, strategy and development for BT Retail. “We are looking at 2007 to be a stabilization year for IPTV services. We still have to get customers used to the idea they can get TV through a broadband connection and scale up as a technical product.”
Akshay Sharma, research director for carrier network infrastructure and converged infrastructure for Gartner/Dataquest, believes IMS will bring a lot of value to IPTV, but admits most of the service provider requests for proposals he has seen focus IMS more on the voice space.
At best, the near future holds the possible blending of IMS with Web services to deliver new IPTV functionality, said Stuart Elby, vice president of network architecture and enterprise technology for Verizon.
“We continue to be convinced that we need to blend the IPTV protocols, a lot of which are Web services-based, with IMS for new service creation,” he said. “For most of what video viewing is about, however, Web services protocols are the right protocols.”
IMS will bring significant value to IPTV in the long term, and service providers setting up closed IPTV systems today need to keep that in mind, Sharma said.
“I'm in the camp that if you look at what IMS brings, there is a lot of value that it brings to the IPTV equation,” he said. “For example, some of the key problems-three-second channel changing delays, quality of service and the user experience aspect that prevent wide-scale deployment-these are places where IMS can help. Its policy decision functions bring about end-to-end policy enforcement, policy control of bandwidth and controls routers end-to-end. IPTV, especially if it's high definition, will need end-to-end bandwidth management.”
In addition, he said, IMS has subscriber databases in its home subscriber servers and other subscriber profiles that can be used both to minimize channel-changing delays by proactively predicting what an individual will watch and cacheing that content closer to the user while targeting advertising.
Sharma and others agree that IMS will be essential when service providers want to start tying together their IPTV deployments with other services, such as cellular, for service mobility.
“IMS has voice call continuity between Wi-Fi and cellular, so sessions are maintained,” Sharma said. That same functionality can be used in the video world so that a cell phone becomes a remote control device that can be used to launch sessions that ultimately wind up on a PC, a TV or even a conference room set up, he said.
“IP gives you a lot of power and flexibility, but you need more intelligence-things like location awareness and presence awareness-that IMS can give you,” he said.
Nortel Networks is conducting two trials with carriers doing IPTV over IMS and finds “it creates such a richer experience, there are so many more things you can do if you take the standards-based approach,” said Sita Lowman, IMS market development leader for Nortel. “I think of the integrated aspect within the TV context. You have integrated presence, so I can IM with a friend while watching TV. When a phone call comes in, I get calling line ID and decide to take that call, so I click to call to ring my home phone. I'm watching ‘American Idol,’ and I'm televoting instead of looking for my phone-being a participant in reality TV shows and gaming instead of just watching.”
And although many of those functions can be implemented without IMS, doing it within that standards-based context will eventually make more sense and be more economic, service providers agree.
“We think IMS has an advantage longer term, when you want to not just create a new service but replicate it over and over,” Verizon's Elby said. “Today, we may write something as a stovepipe application in the Web services model, but what we want to do is write it once in IMS and then use it over and over again. The sooner I get IMS out there, the easier it will be.”
“With anything like this, you always have a choice as to how you try to do it,” said Griffiths of BT Retail, which is implementing Microsoft TV. “One of the beauties of having IMS in the network is that you don't want to keep reinventing the same components. There is a trade-off between speed to market, which usually involves a more stovepipe approach, initially, and a more strategic goal, which should ultimately give you significantly greater speed to market but more challenges to get there.”
Planning to incorporate IPTV into IMS also opens the doors for more heterogeneous applications, said Manuel Vexler, vice president of the IMS Forum.
“Service providers can create their own ecosystem,” he said. “They can think that IMS is too immature and do their own thing and be happy. In that model, it fits well even with the quad play for companies in the top of Tier 1-companies which own all the types of properties they need. However, it is no guarantee that within their ecosystem, innovation will happen on top of all of your offerings. What happens when you need to connect to another competitor-you will have to push your suppliers to come up with the solution and the other company will have to push theirs to come to a connection point with a similar solution.”
Although IMS will become useful when service providers want to integrate services, such as voice, or provide mobility-or integrate applications or technologies from multiple vendors-“it's probably 18 months before operators are going to be demanding those applications for trial,” said Gary Southwell, director of IPTV solutions for Juniper Networks. “There are quite a few that want to walk before they run-get the basic services up and get more subscribers on their systems before they get into advanced capabilities.”
IPTV doesn't require IMS-like functionality to do the basics of delivering video services into the home, industry experts agree. Although IPTV standards are still very much a work in progress at the Alliance for Telecommunications Industry Solutions, the services being deployed today-many of which run on closed or proprietary systems-leverage existing IP standards from the IEEE and the Internet Engineering Task Force (IETF) and International Telecommunications Union (ITU).
“We can leverage a lot of the IETF/IEEE/ITU standards that already exist,” Southwell said. “It is an underlying IP transport, and we can rely on more simplistic QoS such as provided by the IEEE to make sure you can have multiple traffic types going out to the home but sharing the same pipe. And then IPTV can just use multicast, which was standardized back in the IETF many years ago, to handle channel changes.”
The real question, however, is whether IPTV set-tops will evolve to incorporate session initiation protocol (SIP) that is the foundational signaling of IMS and how that will happen.
Today, IPTV set-tops typically deploy real-time streaming protocol (RTSP) or busy room media storage demand and control-an IETF standard, said Suraj Shetty, senior director of service provider marketing for Cisco Systems.
“When you are signaling for pausing, fast-forwarding, [digital video recorder] recording-that's where you need RTSP or SIP,” he said. “Where the IMS guys are coming from, it's, ‘Let's use SIP for everything.’ That's great, but the market is already moving with RTSP. So if I go with SIP — do I need a new set-top box? It creates a transition problem.”
With IPTV, as with voice over IP (VoIP), it isn't necessary to launch the service in the IMS realm, said Mitch Simcoe, senior manager of VoIP/IMS product marketing for Nortel. “You can go down the current IPTV path and start building IMS for voice and data and pull the video later as a video application,” he said. “It is a multistep environment.”
Nortel is building technology that will interwork SIP into existing set-top boxes, using middleware that can be downloaded for upgrading boxes in the field.
Matt Beal, chief technology officer of BT Wholesale, believes IMS standards bodies have to directly address IPTV issues, “If IMS is going to play in the multimedia world,” or service providers will already have chosen competing IPTV-only solutions.
That's an outcome that analyst Sharma believes will limit greatly what IPTV can do. “This is definitely something the industry needs to address,” he said.