A method for initiating a roaming communication link between a user equipment and a visited communication network, the method comprising: transmitting a registration request by the UE to a network entity of the visited communication network, wherein the registration request comprises an identity (UE ID) of the user equipment; detecting by the network entity of the visited communication network, based on the UE ID, that the registration request is related to a roaming communication with the UE; determining by the network entity of the visited communication network a home communication network of the UE; retrieving, by the network entity of the visited communication network, via a communication interface between the network entity and a remote data layer entity, subscriber-specific data of the UE from a data repository of the remote data layer entity of the visited communication network for initiating the roaming communication link of the UE in the visited communication network, wherein retrieving the subscriber-specific data of the UE is based on data base functions which only require a memory address for retrieving the user-specific data, wherein the memory address comprises a Public Land Mobile Network (PLMN) ID of another PLMN than the home communication network, wherein the RDL entity is coupled to the home communication network of the UE via a data base interface (206, 207) configured to retrieve the subscriber-specific data of the roaming UE from the home communication network; initiating by the visited communication network the roaming communication link with the UE based on the subscriber-specific data of the UE received via the RDL entity; and synchronizing, by the home communication network or by the visited communication network, the subscriber-specific data of the RDL entity with corresponding subscriber-specific data stored in the home communication network. transmitting a registration request by the UE to a network entity of the visited communication network, wherein the registration request comprises an identity (UE ID) of the user equipment; detecting by the network entity of the visited communication network, based on the UE ID, that the registration request is related to a roaming communication with the UE; determining by the network entity of the visited communication network a home communication network of the UE; retrieving, by the network entity of the visited communication network, via a communication interface between the network entity and a remote data layer entity, subscriber-specific data of the UE from a data repository of the remote data layer entity of the visited communication network for initiating the roaming communication link of the UE in the visited communication network, wherein retrieving the subscriber-specific data of the UE is based on data base functions which only require a memory address for retrieving the user-specific data, wherein the memory address comprises a Public Land Mobile Network (PLMN) ID of another PLMN than the home communication network, wherein the RDL entity is coupled to the home communication network of the UE via a data base interface (206, 207) configured to retrieve the subscriber-specific data of the roaming UE from the home communication network; initiating by the visited communication network the roaming communication link with the UE based on the subscriber-specific data of the UE received via the RDL entity; and synchronizing, by the home communication network or by the visited communication network, the subscriber-specific data of the RDL entity with corresponding subscriber-specific data stored in the home communication network.