A few years ago, when it seemed apparent that all communications are moving to an IP based world, mobile operators had to decide on the standard to use in their all-IP world. SIP was selected for that purpose as the base protocol, with a lot of additional protocols taking part to comprise the whole network. The end result (which is an ongoing standardization effort) is IMS – the IP Multimedia Subsystem.
IMS was adopted by all other incumbent service providers – wireline, wireless and cable, which in a way made sure of continuity of service, interoperability and roaming between operators. Fun as it is, the problem with IMS is its complexity: it comes to replace a hundred years of developments in voice technologies, and wrap into their future network advanced services such as rich multimedia and presence. [Read more...]