Method and server for performing capability discovery

Home server of a home domain for performing a capability discovery comprising:

• a processor;
• a memory;
• at least one input/output module constructed and arranged to receive from a user terminal a principal discovery request comprising a complete contact list,
• wherein the processor is constructed and arranged to execute instructions contained in the memory in order to determine, from the complete contact list, which contacts are locally known in the home domain, and which contacts are locally unknown in the home domain to generate a limited contact list;
• and wherein the input/output module is constructed and arranged to send to a plurality of remote servers, for all contacts that are locally unknown in the home domain, a plurality of secondary discovery requests comprising the limited contact list, to receive from each remote server a notification containing capability discovery contact information about contacts contained in the limited contact list, including which contacts are remotely known and remotely unknown in each remote server of a respective remote domain, and to send, for each unknown contact both locally unknown by the home server and remotely unknown to the plurality of remote servers, a back-end subscription to a home IMS core.