7.2 Interworking between CS networks supporting ISUP and the IM CN subsystem

29.1633GPPInterworking between the IP Multimedia (IM) Core Network (CN) subsystem and Circuit Switched (CS) networksTS

The control plane between CS networks supporting ISUP and the IM CN subsystem supporting SIP, where the underlying network is SS7 and IP respectively is as shown in figure 2.

Figure 2: Control plane interworking between CS networks supporting ISUP
and the IM CN subsystem