A method for delivering information on a serving mobile switching centre server for an user equipment between a first communication network and a second communication network. The method includes a step of requesting an attachment of the user equipment to the second communication network by signaling between the user equipment and a network node of the second communication network, the signaling including at least part of information on the mobile switching centre server serving the user equipment in the first communication network. Additionally, an user equipment and a network node implementing the aspects of the method are described.