Patent ID: 8041795

Claim:
An arrangement for a first operator network providing an IP Multimedia System (IMS) service to a first user by means of an IMS interconnect network, the first operator network comprises a Domain Name System (DNS) system comprising at least an external DNS to the first operator network and an internal DNS to the first operator network and the IMS interconnect network comprises at least an IMS interconnect DNS, wherein the arrangement comprises an interface to the IMS interconnect DNS and the DNS system of the operator network to be used by the first user, and means for administering the IMS interconnect DNS and the DNS system of the operator network to be used by the first user via said interface, the means for administering comprising: a processor adapted to establish a predefined domain, the processor further adapted to connect a user as a member of the predefined domain by providing the user, to be connected, an identity associated with the predefined domain, the processor further adapted to insert the established predefined domain in the IMS interconnect DNS and in the DNS system of the operator network to be used by the first user and the processor further adapted to insert members of the established predefined domain in the DNS system of the operator network to be used by the first user such that queries relating to users being members of the established predefined domain are forwarded to the external DNS of the first operator network, the processor further adapted to establish the identity associated with established predefined domain as a Private domain name based IMS public user ID (IMPU) associated to the IMS identity of the user, to be connected, to the established predefined domain, in the IMS interconnect network, and wherein the processor is further adapted to configure the external DNS of the operator network to be used by the first user such that a service (SRV) record associated with the established predefined domain is configured to define the identity of a member of the established predefined domain and is configured to point to said member's Fully qualified Domain Name of the operator network's entry point from the IMS interconnect DNS.