Domain managing method, domain extending method and reference point controller electing method

A domain management method, a domain extending method thereof and a reference point controller electing method thereof are provided to recover the function of a reference point controller by using reference point controller candidates when the reference point controller has a problem. A domain management method comprises the steps of: receiving a request from reference point controller candidates concerned with reference point controller authentication by using managers which manages domains(S300); invalidating a stored reference point controller member token(S301); creating a unique reference controller member token which proves the permission that the reference point controller candidates are new reference point controllers(S302); and transferring the created reference point controller member token to the reference point controller candidates(S303).