Thursday, April 26, 2007
IMS for Fixed Operators
Fixed and mobile operators tend to have very different perceptions of IMS.
The introduction of IMS in the fixed domain is relatively recent, as it dates from the decision of ETSI TISPAN in 2003 or 2004 to include 3GPP IMS as part of its Next Generation Network (NGN) architecture. The fixed version of IMS consists of extensions to 3GPP IMS (new entities, new behaviors in existing IMS entities), which makes that an IMS core network complying with both 3GPP and TISPAN specifications can simultaneously support fixed and mobile access.
For fixed operators, IMS enables both VoIP and other "multimedia" services (this potential for new services is one argument to distinguish IMS from a more classic softswitch architecture). The fact that IMS is a common technology between mobile and fixed access also permits these operators to envisage offering their services to mobile handsets by becoming a Mobile Virtual Network Operator (MVNO), thus hitting back to the Fixed Mobile Substitution problem of the last years.
IMS is part of the "new generation" network that will replace the aging, heterogeneous, and costly circuit-switched network used for 1st line telephony. In this context, IMS can support the quality of service, the scalability, the reliability, the security, and the regulation constraints currently associated to a PSTN service, while simpler VoIP implementations already deployed by fixed operators can remain 2nd line cheap telephony alternatives to Skype, Gizmo, Google Talk and others.
Therefore, contrary to mobile operators, fixed operators thinking about replacing their circuit-switched network have a good reason to deploy IMS, and many will want to start introducing it fast (phasing out the old network and migrating subscribers to the new one is not an easy and instant process). For once in telecommunications, many operators are eager to introduce in their network a technology whose standardization/implementation (i.e. adaptation of 3GPP "multimedia" and mobile IMS to voice-centric and fixed requirements) is still not completed.
The not so positive side of the story is that the focus put on simulating plain old telephony services makes that fixed operators usually dedicate little effort to think of the next steps, and what IMS can offer beyond being a systematic replica of how a circuit-switched network works. This also largely contributes to the perception that IMS is just a technology to re-create the old telco world over IP.
This is a pity, because fixed operators have important IMS-related assets compared to mobile operators: no bandwidth problems, the possibility to rely on the openness of personal computers to easily test and introduce innovative services, and the possibility to find interesting synergies with newly introduced services like IPTV.
It should also be noted that re-creating on technologies like IP and IMS a legacy user experience created decades ago on a network optimized for it is not a simple thing. Some of the complexity is related to the need to artificially recreate a (limited) legacy user experience with a network and a protocol, which were made to naturally support a much richer one. This may lead to fixed network technicians complaining about the unability of IMS and SIP to faithfully and optimally replicate circuit-switched features while the same technicians totally ignore alternative and better features provided by the technology.