Techniques for improved service call session restoration

A Home Subscriber Server (HSS) computing device comprising:

• one or more processors;
• and
• one or more non-transitory computer-readable media storing computer-executable instructions that, when executed by the one or more processors, cause computing device to perform operations comprising:
• storing information about a proxy call session control function (P-CSCF) node in association with information about a specific user equipment (UE) that has a connection supported by the P-CSCF node;
• receiving an indication that a first service call session control function (S-CSCF) node is unresponsive, wherein the first S-CSCF node was also associated with the connection of the specific UE;
• selecting, based on the information about one or more capabilities, a second S-CSCF node to replace the first S-CSCF node for the connection of the specific UE, wherein the second S-CSCF node is selected from a set of S-CSCF nodes determined to be available and the set of S-CSCF nodes determined to be available is identified based on a current workload or bandwidth usage;
• receiving, from the second S-CSCF node, a request for the information about the P-CSCF node;
• and
• providing at least a portion of the information about the P-CSCF node to the second S-CSCF node.

A system comprising:

• at least one proxy call session control function (P-CSCF) node;
• multiple service call session control function (S-CSCF) nodes;
• and
• a home subscriber server (HSS) configured to:
• store information about the P-CSCF node in association with information about a specific user equipment (UE) that has a connection supported by the P-CSCF node;
• receive an indication that a first S-CSCF node of the multiple S-CSCF nodes is unresponsive, wherein the first S-CSCF node was also associated with the connection of the specific UE;
• select, based on the information about one or more capabilities, a second S-CSCF node to replace the first S-CSCF node for the connection of the specific UE;
• receiving, from the second S-CSCF node, a request for the information about the P-CSCF node;
• and
• provide at least a portion of the information about the P-CSCF node to the second S-CSCF node.