Restoration of a PDN connection at PGW failure

A network node that implements a Mobility and Management Entity, MME, for a cellular communications system, the network node comprising processing circuitry configured to cause the network node acting as the MME to:

• receive an attach request from a User Equipment, UE;
• send a location update request to a Home Subscriber Station, HSS;
• receive a location update acknowledgement from the HSS;
• send a Domain Name Server, DNS, query request to a DNS, the DNS query comprising an Access Point Name, APN, Fully Qualified Domain Name, FQDN;
• receive 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;
• select the first combined SMF/PGW-C instance;
• send, to a Serving Gateway, SGW, a first create session request that comprises information that indicates the first combined SMF/PGW-C instance;
• receive a first create session response from the SGW;
• and
• sending an attach accept to the UE.