Access method in wireless communications network, related apparatus, and system

An access method in a wireless communications network, comprising:

• after user equipment UE accesses a non 3rd Generation Partnership Project 3GPP access network, receiving, by a mobility management network element that supports authentication and authorization functions for the non-3GPP access network, an authentication and authorization request message sent by a non-3GPP access gateway, wherein the authentication and authorization request message is used to request to perform authentication and authorization for the UE;
• performing, by the mobility management network element, authentication and authorization for the UE according to the authentication and authorization request message;
• after successfully performing authentication and authorization for the UE, receiving, by the mobility management network element, an access point name APN of the UE and an identity of a packet data network gateway P-GW that are sent by the non-3GPP access gateway, wherein the P-GW is selected by the non-3GPP access gateway for the APN of the UE;
• and
• sending, by the mobility management network element, the APN of the UE and the identity of the selected P-GW to the HSS.

A method for updating subscription data, comprising:

• receiving, by a mobility management network element, a data update request message sent by a home subscriber server HSS after subscription data of user equipment UE is updated, wherein the data update request message comprises an international mobile subscriber identity IMSI of the UE, updated subscription data of the UE, and an access type corresponding to the updated subscription data, and the data update request message is an insert subscription data message, a push subscription request message, or an insert subscriber data message;
• determining, by the mobility management network element according to the data update request message, a target gateway corresponding to the access type;
• and
• sending, by the mobility management network element, an update message to the target gateway, wherein the update message is used to request the target gateway to update the subscription data of the UE, and the update message comprises the updated subscription data of the UE and the IMSI of the UE.