During the production of the 3GPP Release 7 specifications it was recognized that the IP Multimedia Subsystem was suitable for serving both mobile and fixed installations and a number of specifications developed by ETSI TISPAN were therefore embedded in the 3GPP specifications to form the Common IMS. Among other aspects, Common IMS requires that the IMS is able to connect with Next Generation Corporate Networks (NGCN), also known as IP-PBXs (see ETSI TS 181 019).
Managing the connection to IP-PBXs which do not use registration procedures when connecting to the IMS and operate in a static mode that is to enable the IMS to receive and send traffic to an IP-PBX, is realized by means of configuration within the network. The static mode of operation can be used in 2 scenarios, peering based business trunking and subscription based business trunking. The static mode of operation for both of the above mentioned scenarios can be studied in this TR.
It was however observed that the number of implementations of IP-PBXs that are operated in a static mode (e.g. based on the SIPConnect specifications recently released by the SIP Forum) increases.
The purpose of this study is to enable the IMS to manage connections to a large number of IP-PBXs that are operated in a static mode, with minimized configuration in the network.