SERVICE REQUEST HANDLING METHOD AND DEVICE AND COMMUNICATION SYSTEM

Embodiments provide a service request processing method, a related device, and a communications system in an IMS network. In the embodiments, because 5GC network slices correspond to different services, P-CSCFs in the IMS also correspond to different service information. After receiving a terminated service request sent by an I-CSCF, a first S-CSCF can obtain an address of a corresponding P-CSCF based on terminated service information carried in the terminated service request. Then, the first S-CSCF sends the terminated service request to the P-CSCF corresponding to the address, and the P-CSCF processes the terminated service request. The embodiments resolve a technical problem of how an S-CSCF in the IMS sends a terminated service request for UE to a corresponding P-CSCF for processing after the UE accesses the IMS through different 5GC network slices.