Patent ID: 11870854
Assignee: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC G  H

Claim 8:
9. A method of operation of a Mobility and Management Entity, MME, for a cellular communications system, the method comprising:
receiving an attach request from a User Equipment, UE;
sending a location update request to a Home Subscriber Station, HSS;
receiving a location update acknowledgement from the HSS;
sending a Domain Name Server, DNS, query request to a DNS, the DNS query comprising an Access Point Name, APN, Fully Qualified Domain Name, FQDN;
receiving a DNS query response from the DNS, the DNS query response comprising information that:
identifies a plurality of candidate combined Session Management Function and Packet Gateway Control Plane, SMF/PGW-C, instances that satisfy the DNS query request; and
identifies at least two candidate combined SMF/PGW-C instances that belong to a same SMF/PGW-C set, the at least two combined SMF/PGW-C instances comprising a first combined SMF/PGW-C instance and a second combined SMF/PGW-C instance, where the SMF/PGW-C instances in the SMF/PGW-C set support the same services and the same Network Slice(s);

selecting the first combined SMF/PGW-C instance;
sending, to a Serving Gateway, SGW, a first create session request that comprises information that indicates the first combined SMF/PGW-C instance;
receiving a first create session response from the SGW;
sending an attach accept to the UE;
determining that the first combined SMF/PGW-C instance has failed;
responsive to determining that the first combined SMF/PGW-C instance has failed:
sending a second create session request to the SGW or a new SGW, the second create session request comprising information that indicates the second combined SMF/PGW-C instance; and
receiving a second create session response from the SGW or the new SGW.