Registration switching method, request processing method, information sending method, and related device

A registration switching method, wherein the method is applied to a terminal supporting a narrowband (NB) capability and a wideband (WB) capability and comprises:

• camping on a network node supporting an NB service, and performing combined registration with a network supporting the NB service and a network supporting a WB service;
• and
• switching to a network node supporting the WB service, to transmit the WB service;
• wherein before the switching to a network node supporting the WB service, to transmit the WB service, the method further comprises:
• sending a second message to the network node supporting the NB service, wherein the second message is used to request the WB service;
• or
• receiving a third message sent by the network node supporting the NB service, wherein the third message is used to indicate that downlink data of the WB service is to be sent.