I'm at a SIP conference in Brussels. I've heard quite a few presentations on SIP and IMS, and I'm speaking later today about handsets.
As usual, I am struck by the ostrich-like viewpoint of many legacy mobile operators in insisting that IMS will be at the core of users' future interactive/online usage. I've heard assorted pitches describing interoperability of different operators' presence servers, or a video-sharing interoperability trial run by the GSMA with 57 participants. All of these conspicuously fail to talk about interoperation with other IM/presence/SIP domains, apart from maybe a fluffy cloud marked "other providers" on a chart, linked in to the ever-dodgy IPX pseudo-Internet concept.
Now, I reckon there's probably close on a billion SIP or SIP-like end-points out there already - VoIP, Internet IM devices and clients and so forth. Some are PC-based, some mobile-based, some as dedicated phones or ATAs. Sure, some are proprietary, but why not work on gateways rather than ignore them? This isn't "other", this is "vast majority".
At the moment, the GSMA and IMS-oriented operators are a "coalition of the losers" in terms of SIP deployment. The idea that joining up lots of services, each with zero subscribers, will somehow oust Yahoo, Microsoft, Vonage, Cisco, Skype etc is risible. Last time I checked my calculator, 57 x zero = zero.
Interestingly, I'm starting to see representatives of the operators' R&D departments start to talk a bit more sense. One speaker from a major carrier's lab talked about peer-to-peer SIP and the competition between "service" and "application". Another talked about lessons from Web 2.0, and how SIP could enable monetisation of "the long tail" of potential IMS/SIP applications, and foster the type of "perpetual beta" model seen on the web.
Just a pity that this dose of reality hasn't made it through to some of the IMS architecture and business development guys.....
I'll be pushing people to discuss this at next week's IMS Services Forum in London