A method of supporting
authentication of a
user equipment, UE, in an
Internet Protocol, IP,
Multimedia Subsystem, IMS, telecommunication network by connecting a Service Based Architecture, SBA, telecommunication network, the method comprising the steps of: receiving, by a Unified
Data Management, UDM, in the SBA telecommunication network, binding information from a
Session Management Function, SMF, in the SBA telecommunication network, wherein the binding information is used to identify the UE in the IMS telecommunication network; receiving, by the UDM in the SBA telecommunication network, a request to provide the binding information from a
Home Subscriber Server, HSS, in the IMS telecommunication network; and providing, by the UDM in the SBA telecommunication network, the binding information to the HSS in the IMS telecommunication network, thereby supporting
authentication of the UE. Supplementary methods and corresponding nodes are also presented herein.