I reckon that the entire Internet & IT community is negative towards IMS – Google, Microsoft, Yahoo, Skype et al.
IMS = walled-garden SIP, or perhaps more amusingly an “Internet Monetisation System”.
The problem is that IMS views everything as a billable ‘service’ – it doesn’t seem to accept that certain applications are based on the customer owning or operating their own software. In the real world, customers want certain capabilities delivered as ongoing sbillable ervices (opex) and certain things bought, owned & used outright (capex)
The current setup of the Internet is that centrally-controlled QoS and charging is anathema. IMS harks back to the legacy days of bundling access & service. That’s fine for certain things, but totally inappropriate for the Internet, as that control adds latency & friction to development & innovation. I’ve heard IMS vendors talk about developers and “2 men & a dog in a garage”, when what they actually meant was “2 men, a dog & a 30-person legal department”.
As a simple example – could you imagine that anything as mindbogglingly useful as PDF would have evolved had the Internet been based on IMS principles? Download the client for free & then use it in perpetuity as a browser plug-in? No, we would all have been charged for a usage-based ‘document viewing service’, and it would never have got the traction.
The one thing that could change the situation is if one of the vendors – perhaps Cisco or Avaya – invented a private IMS architecture, that enterprises or large Internet firms could own. It would be deeply amusing if Merrill Lynch or GlaxoSmithKline deployed their own IMS’s, and started charging interconnect fees to the telcos.