Methods, systems, and computer readable media for providing federated network interoperability in the absence of acesss token authorization support in the home network

A non-transitory computer readable medium having stored thereon executable instructions that when executed by a processor of a computer control the computer to perform steps comprising:

• discovering, by a security edge protection proxy (SEPP), network function (NF) profiles of consumer NFs allowed to send inter-public land mobile network (inter-PLMN) service-based interface (SBI) request messages;
• receiving, by the SEPP, an access token request message from a visited NF repository function (NRF) requesting an access token on behalf of a consumer NF to access a service in a home network;
• storing, by the SEPP, parameter values from the access token request message;
• forwarding, by the SEPP, the access token request message to the home network;
• receiving, by the SEPP, from the home network, and in response to the access token request message, an error message;
• authorizing, by the SEPP, the consumer NF;
• generating, by the SEPP, an access token, generating an access token response message, and transmitting the access token response message including the access token to the visited NRF;
• and
• receiving, by the SEPP and from the consumer NF, an inter-PLMN SBI request message including the access token, verifying the access token, removing the access token from the inter-PLMN SBI request message and forwarding the inter-PLMN SBI request message to the home network.