A communication method, comprising: obtaining, by a first mobility management network element (180, 190) which is an access and mobility management function, AMF, in a first network which is a 5th generation, 5G, network, information about N intermediate session management network elements, I-SMFs, that are capable of serving a terminal in the first network, wherein the N intermediate session management network elements comprise a combined intermediate session management network element, the combined intermediate session management network element is capable of providing session management in the first network and is capable of providing session management in a second network which is a 4th generation, 4G, network, so that the combined intermediate session management network element is an I-SMF plus a serving gateway control plane function, SGW-C, and N is an integer greater than 0; and determining, by the first mobility management network element (180, 190), that the combined intermediate session management network element is a first intermediate session management network element corresponding to a first session of the terminal in the first network, wherein an intermediate session management network element that is in the information about the N intermediate session management network elements and that comprises indication information is the combined intermediate session management network element, and the method further comprises: determining, by the first mobility management network element (180, 190), the combined intermediate session management network element based on the indication information. obtaining, by a first mobility management network element (180, 190) which is an access and mobility management function, AMF, in a first network which is a 5th generation, 5G, network, information about N intermediate session management network elements, I-SMFs, that are capable of serving a terminal in the first network, wherein the N intermediate session management network elements comprise a combined intermediate session management network element, the combined intermediate session management network element is capable of providing session management in the first network and is capable of providing session management in a second network which is a 4th generation, 4G, network, so that the combined intermediate session management network element is an I-SMF plus a serving gateway control plane function, SGW-C, and N is an integer greater than 0; and determining, by the first mobility management network element (180, 190), that the combined intermediate session management network element is a first intermediate session management network element corresponding to a first session of the terminal in the first network, wherein an intermediate session management network element that is in the information about the N intermediate session management network elements and that comprises indication information is the combined intermediate session management network element, and the method further comprises: determining, by the first mobility management network element (180, 190), the combined intermediate session management network element based on the indication information.