<P> To ease the integration with the Internet , IMS uses IETF protocols wherever possible , e.g. , SIP ( Session Initiation Protocol ) . According to the 3GPP , IMS is not intended to standardize applications , but rather to aid the access of multimedia and voice applications from wireless and wireline terminals , i.e. , to create a form of fixed - mobile convergence ( FMC ) . This is done by having a horizontal control layer that isolates the access network from the service layer . From a logical architecture perspective , services need not have their own control functions , as the control layer is a common horizontal layer . However , in implementation this does not necessarily map into greater reduced cost and complexity . </P>
what does sip stand for in the ngn / ims context
Session Initiation Protocol