Redirecting a call by a circuit switched network to an internet protocol multimedia subsystem (IMS) network

A device receives a call for a user device associated with an Internet protocol multimedia subsystem (IMS) network, where the call includes a mobile directory number (MDN) associated with the user device, and retrieves, from a home location register (HLR), an address of a wireless intelligent network (WIN) termination trigger service control point (SCP). The device sends, to the WIN termination trigger SCP, a first message that includes the MDN, receives, from the WIN termination trigger SCP, a second message that includes steering digits as a prefix to the MDN, and generates a third message that includes a called party number set to the MDN and omits the steering digits. The device also routes, based on the steering digits, the third message to a media gateway control function/media gateway (MGCF/MGW) of the IMS network, where the MGCF/MGW further processes the call.