Method for obtaining serving gateway, mobility management node, data gateway, and system

A mobility management node, comprising:

• a sending unit, configured to send a domain name resolution request to a domain name system (DNS) server according to access information of a user equipment (UE), wherein the access information comprises an access point name (APN) of the UE or an old-side location area identity of the UE;
• a receiving unit, configured to receive a hostname of a device returned, according to the domain name resolution request, by the DNS server;
• an obtaining unit, configured to obtain a hostname of a new-side available serving gateway (S-GW);
• and
• a selecting unit, configured to select the new-side available S-GW closest to the device on geographic topology as a new-side S-GW according to a part, in the hostname of the device, denoting a geographic topological relationship and a part, in the hostname of the new-side available S-GW, denoting a geographic topological relationship.

A system for obtaining a serving gateway (S-GW), comprising:

• a mobility management node and a domain name system (DNS) server;
• wherein the mobility management node is configured to:
• send a domain name resolution request to a domain name system (DNS) server according to access information of a user equipment (UE), wherein the access information comprises an access point name (APN) of the UE or an old-side location area identity of the UE,
• receive a hostname of a device returned, according to the domain name resolution request, by the DNS server;
• obtain a hostname of a new-side available S-GW;
• and
• select the new-side available S-GW closest to the device on geographic topology as a new-side S-GW according to a part, in the hostname of the device, denoting a geographic topological relationship and a part, in the hostname of the new-side available S-GW, denoting a geographic topological relationship.