The objective of this study item is to identify and document methods to guarantee that all the relevant charging data for an IMS session has been received in order to charge the IMS session correctly.
Within the study scenarios could be covered where a concatenation of applications leads to an correlation of charging relevant information.
In addition a method to identify all network elements generating CDR for offline charging within an IMS call in order to serve for an effective and accurate IMS Charging correlation is in focus of this study.
The following scenarios are be covered this study:
IMS calls where the service invocation is done in the originating and/or terminating home network. Scenarios to be considered should cover different network scenarios like roaming, transit, PSTN interworking, intra home network or home-a to home-b network. IMS Calls where a concatenation of applications appear. The invoked applications can be provided by AS from different networks.
IMS Calls where an Application Server hosts several applications invoked during one call.
IMS Calls where call leg manipulation apply and more than one application is involved.
IMS Calls where only several IMS network elements are necessary to generate charging information based on operator's configuration.
IMS Other scenarios where a correlation of charging relevant information created by application servers is needed.
The study will identify recommended enhancements to the charging architecture, message and CDR content, and internode signalling.
It will analyse operator requirements in consideration of the roaming scenarios and the existing charging specifications.
The conclusions are presented in a further section with assumptions made and proposed further proceedings on that issues.