The GetRPCMethods argument is used by both the CPE and the ACS to request a list of the RPCs supported by either endpoint to better understand the endpoint’s capabilities. It’s one of the simpler RPCs in that it contains no arguments.
In the response, the ACS or CPE MUST include all of the required RPCs specified in TR-069, and may include additional optional RPCs or vendor defined RPCs.
For the ACS, these required RPCs include, Inform, GetRPCMethods, and TransferComplete
For the CPE, the require RPCs are GetRPCMethods, SetParameterValues, GetParameterValues, GetParameterNames, GetParameterAttributes, SetParameterAttributes, AddObject, DeleteObject, Reboot, and Download.
To define a vendor specific RPC, the method must be of the following form:
The method starts with X underscore, followed by a unique vendor identifier, usually an official OUI or domain name. After another underscore, the custom RPC is named.
Keep in mind that vendor extensions need to be understood to exist ahead of time or defined in a custom schema in order to be understood by the CPE or ACS.