A method of providing a communication service for a wireless device registered in a home network and that is roaming in a visited network, the visited network comprising routing means (V-MSC/VLR, V-SGSN), characterized in that the method comprises the following steps: • provisioning the routing means (V-MSC/VLR, V-SGSN) of the visited network with a plurality of identifiers that identify a plurality of wireless devices that are registered in the home network, defining thereby in the visited network a plurality of provisioned wireless devices; • provisioning the routing means (V-MSC/VLR, V-SGSN) of the visited network with an address of a module (V-MLR) located in the visited network and comprising at least a home location register (V-HLR), and assigning the address of the module (V-MLR) to the plurality of identifiers provisioned in the routing means (V-MSC/VLR, V-SGSN), so that the routing means (V-MSC/VLR, V-SGSN) can access the address of the module (V-MLR) located in the visited network based on an identifier of the plurality of provisioned identifiers; • at the routing means (V-MSC/VLR, V-SGSN) of the visited network: - receiving (101, 107, 108, 115) a message from a wireless device, the message comprising at least an identifier; - determining, based on said identifier, whether the message is received from a provisioned wireless device; - if the message is received from a provisioned wireless device, then determining, based on said identifier, the address of said module (V-MLR) that is assigned to the provisioned wireless device and then, based on this address, sending (102, 109, 116) to said module (V-MLR) located in the visited network and comprising at least a home location register (V-HLR) at least one of: - an authentication request message if the message received from the provisioned wireless device is a request for attachment; - an update location message if the message received from the provisioned wireless device is a response to an identity request, the identity request being exchanged during a phase of update location of the wireless device. • provisioning the routing means (V-MSC/VLR, V-SGSN) of the visited network with a plurality of identifiers that identify a plurality of wireless devices that are registered in the home network, defining thereby in the visited network a plurality of provisioned wireless devices; • provisioning the routing means (V-MSC/VLR, V-SGSN) of the visited network with an address of a module (V-MLR) located in the visited network and comprising at least a home location register (V-HLR), and assigning the address of the module (V-MLR) to the plurality of identifiers provisioned in the routing means (V-MSC/VLR, V-SGSN), so that the routing means (V-MSC/VLR, V-SGSN) can access the address of the module (V-MLR) located in the visited network based on an identifier of the plurality of provisioned identifiers; • at the routing means (V-MSC/VLR, V-SGSN) of the visited network: - receiving (101, 107, 108, 115) a message from a wireless device, the message comprising at least an identifier; - determining, based on said identifier, whether the message is received from a provisioned wireless device; - if the message is received from a provisioned wireless device, then determining, based on said identifier, the address of said module (V-MLR) that is assigned to the provisioned wireless device and then, based on this address, sending (102, 109, 116) to said module (V-MLR) located in the visited network and comprising at least a home location register (V-HLR) at least one of: - an authentication request message if the message received from the provisioned wireless device is a request for attachment; - an update location message if the message received from the provisioned wireless device is a response to an identity request, the identity request being exchanged during a phase of update location of the wireless device. - receiving (101, 107, 108, 115) a message from a wireless device, the message comprising at least an identifier; - determining, based on said identifier, whether the message is received from a provisioned wireless device; - if the message is received from a provisioned wireless device, then determining, based on said identifier, the address of said module (V-MLR) that is assigned to the provisioned wireless device and then, based on this address, sending (102, 109, 116) to said module (V-MLR) located in the visited network and comprising at least a home location register (V-HLR) at least one of: - an authentication request message if the message received from the provisioned wireless device is a request for attachment; - an update location message if the message received from the provisioned wireless device is a response to an identity request, the identity request being exchanged during a phase of update location of the wireless device. - an authentication request message if the message received from the provisioned wireless device is a request for attachment; - an update location message if the message received from the provisioned wireless device is a response to an identity request, the identity request being exchanged during a phase of update location of the wireless device.