Patent ID: 8811954

Claim:
A method comprising: at a serving call session control function (S-CSCF), receiving signaling for an incoming session intended for a user element and originated from a remote endpoint, wherein the user element is configured to support communications via a plurality of domains through corresponding communication clients; storing, in a home subscriber server (HSS), current domain information indicating a circuit switched (CS) domain and a multimedia subsystem (MS) domain in which the user element is concurrently registered and prior domain information identifying the CS domain or the MS domain used for establishing a prior call with the user element; from the S-CSCF, obtaining a selected domain from the plurality of domains for the incoming session from a domain selection function located in the HSS by sending a domain selection query to the domain selection function located in the HSS, wherein the domain selection function in the HSS selects between the CS domain and the MS domain based on the prior domain information and provides a domain selection response to the S-CSCF; and effecting, by the S-CSCF, routing of the incoming session to the user element via the selected domain contained in the domain selection response, wherein effecting routing of the incoming session to the user element via the selected domain contained in the domain selection response includes routing the incoming session to the user element via the CS domain if the domain selection response contains routing information for the CS domain and routing the incoming session to the user element via the MS domain if the domain selection response contains routing information for the MS domain.