CAMEL is to CS domain what IMS is to IP domain. Since we are all moving towards IMS, eventually CAMEL would become obsolete. Another important thing with IMS is that it is access independent and defined for wireless as well as wireline technologies.
IMS will take some time to be implemented and in the meantime CAMEL and IMS will co-exist. In the meantime operators may use CAMEL to control IMS to take advantage of the technology they have heavily invested in and have tested for some years.
CAMEL control of IP multimedia calls forms a bridge between the CS mobile network and the IP multimedia network. The IMS is the IP-based communication system for mobile networks. Although IMS, which was introduced in 3GPP release Rel-5, is specified for the mobile network,
it may also be used for wireline networks. In fact, the nature of IMS facilitates arbitrary access methods to be used.
Some Useful Specs as follows:
- 22.228: Service requirements for the IMS
- 22.250: IP multimedia subsystem group management
- 22.340: IP multimedia subsystem messaging
- 23.228: IP multimedia subsystem
- 23.278: CAMEL – IP multimedia system interworking
- 24.228: Signalling flows for the IP multimedia call control based on session initiation protocol and session description protocol (discontinued after Rel-5)
- 24.229: Internet protocol multimedia call control protocol based on session initiation protocol and session description protocol
- 29.228: IP multimedia subsystem Cx and Dx interfaces; signalling flows and message contents
- 29.229: Cx and Dx interfaces based on the diameter protocol; protocol details
- 29.278: CAMEL application part specification for IP multimedia subsystems
Further Reading: CAMEL: Intelligent Networks for the GSM, GPRS and UMTS Network by Rogier Noldus