CALLBACK SERVICE IN SIP/IMS FROM A VISITED NETWORK WITH A LOCAL NUMBER

摘要

The application relates to a method and means for calling back an originally calling party when the caller is attached to a visiting network and the call is routed by the home network and the caller. dials a local number, i.e. a number conforming to the numbering plan of the visited network where this dial plan does not conform to the E.164 numbering plan. If the routing towards the recipient is provided by an entity in the home network (so called home control model of IMS) the home network cannot utilise the number conforming to the numbering plan of the visited network. This problem is solved in that an entity in the home network stores the numbering plan of the visited network, determines the visited network and transforms this number into an international E.164 format which is subsequently used to do a DNS ENUM query with the number in the E.164 format and to route the call to the address obtained by the DNS ENUM query. In a second embodiment the numbering plan of the visited network is downloaded to the terminal and the terminal translates the number.