A method of initiating a Packet Data Unit, PDU, session between an User Equipment, UE, and a Data Network Name, DNN, in a telecommunication network, said method comprising the steps of; receiving, by an Access & Mobility Function, AMF, a registration request for an UE for registering said UE in said telecommunication network, retrieving, by said AMF, from an Unified Data Management, UDM, node, one or more DNNs to which PDU sessions are expected to be established by said UE in said telecommunication network, and wherein said step of retrieving is triggered by said receiving of said registration request, instructing, by said AMF, said UE to initiate said one or more PDU sessions between said UE and said one or more DNNs. Complementary methods and Devices for performing a method according to the invention are also presented herein.