I have asked nearly all major vendors about the carrier RFPs that require IMS-compliant IPTV solution set. There are no such RFPs floating around … precisely because there are no set IMS specs for IPTV technology. They are still being worked at by the Tispan standards group. It is however common for carriers to seek migration path toward IMS compliance in the IPTV equipment they procure. So what you have in the market is ‘IMS ready’ rather than ‘IMS compliant’ solutions. Thomson and Ericsson seem to be ahead of the curve.
The benefits of an IMS-compliant IPTV solution are obvious. Service providers will be able to offer both voice and IPTV services over the same core infrastructure, leveraging the same CSCF, the same HSS, and the same telephony feature server for instance. There is some interest in that for sure. But if video application server is connected to IMS then any SIP enabled client (which can include mobile phones) can reach this video application server, so that with the same platform you serve multiple devices. There seems to be more service provider interest in the latter.
From ‘IMS-Ready’ to ‘IMS-Compliant’: There are certain challenges in making the present IPTV technology IMS-compliant. Thomson’s IPTV Product Marketing Manager, Thierry Boudard pointed them out to me in a recent conversation. The main hitch seems to be the fact that standards are not ready yet. Some of the IPTV middleware specs will migrate to IMS core boxes. Functionalities like subscriber authentication will migrate to CSCF boxes; user profile including user privileges info will get absorbed into HSS; bandwidth allocation and QoS mechanism, optional right now in IMS, will have to be absorbed in IMS core as well. Most of the present middleware specs will stay in the video application server in the IMS blueprint. What resides on the video application server will be features like VOD management, time-shift, PVR, Anytime TV, ‘Communicating TV’ features etc. This distribution of functionalities has not been finalized yet.
The other challenge is that the end devices like the set-top box must be SIP client. In IPTV set up there is some metadata that needs to be sent to the STB like VOD catalog and EPG info or the Conditional Access rights info. SIP does not handle these types of metadata. So accompanying protocols need to be implemented along with SIP. One other issue is that you cannot really homogenize elements such as encoders for use across various device media. If you resize football video for mobile TV you will not be able to see the ball. You therefore have to optimize an encoder for either IPTV or mobile TV. You cannot use the same platform for both. However Thierry points out that this is not much of a problem as carriers can use multiple encoders in a common headend.
Service providers are aware of the benefits and those that have already invested in IPTV solution have all put pressure on their vendors to demonstrate IMS compliance roadmaps. A couple of these service providers are already testing IMS oriented IPTV ahead of the standardization. Thomson has been involved in such projects. Ericsson is also reported to be ahead of the curve. Thomson is video specialist with IMS knowledge. So the vendor is in a unique position. Ericsson will have edge on IMS front because they are world leader in that area. But they are not video specialists.
The Cirpack softswitch that Thomson acquired has been evolved in to a pure application server architecture. The softswitch has been decomposed into feature server and CSCF boxes. Having achieved that Thomson is now developing interfaces to the video server so that it works in overall IMS architecture. The delay factor is Tispan that has not specified these APIs and standards. That standard is expected to be finalized in 2008. Thomson is co-writer of the related Tispan 2 specs. Ericsson, Orange and others are also contributors.