Bearer-independent circuit-switched core network; Stage 2
The present document defines the stage 2 description for the bearer independent CS core network. The stage 2 shall cover the information flow between the GMSC server, MSC server and media gateways. Note that nothing in the present document shall preclude an implementation of a combined MSC Server and MGW. The present document shall show the CS core network termination of the Iu interface in order to cover the information flow stimulus to the core network and describe the interaction with the supplementary and value added services and capabilities.
For the purposes of the present document, the protocol used over the Nc interface is an enhanced call control protocol supporting call bearer separation such as BICC (which is specified in [22]). The protocol used over the Mc interface is H.248 (which is specified in 3GPP TS 29.232 [6]). Existing specifications and recommendations shall not be repeated, as such the relevant specification shall be referred to.
SIP-I based CS core network is further specified in 3GPP TS 23.231 [42].
Local Call Local Switch (LCLS) functionality is further specified in 3GPP TS 23.284 [45].
The present document is applicable only for ATM or IP transport in the CS core network.
Figure 1: CS core network logical architecture
The CAP interfaces and the interfaces towards the HLR are outside the scope of the present document.
Details of Transcoder-Free Operation are outside the scope of the present document. Please see 3GPPTS 23.153 [3] for more information.
The present document specifies functions, procedures and information which apply to GERAN Iu mode. However, functionality related to GERAN Iu mode is neither maintained nor enhanced.