A routing technique for supporting an internet protocol (IP) Multimedia Subsystem (IMS) Subscriber Locator Function (SLF) is provided. It is, in part, based on using a user's identification information, e.g. a user's realm, to facilitate the routing of information. This technique enables the implementation of a distributed subscriber location function (SLF) in an IMS network. The subscriber locator function (SLF) ultimately allows for accommodation of more users through multiple home subscriber service (HSS) elements.