Patent ID: 7453876
Filing Date: 2008-11-18
Classification: H04L

Abstract:
1. A method for routing in an internet protocol (IP) multimedia subsystem (IMS) incorporating a distributed subscriber locator function, the method comprising: determining by a first network element whether a private user identification including a realm name is available for use in routing using a Diameter Protocol; populating by the first network element a destination-realm attribute value pair of a first Diameter Protocol message with the private user identification if the private user identification is available; performing a subscriber locator function by a first network element to determine a first home subscriber service (HSS) element to which to send the first Diameter Protocol message based on the destination realm attribute value pair; transmitting the first Diameter Protocol message from the first network element to the first home subscriber service (HSS) element; populating by the first network element the destination-realm attribute value pair of a second Diameter Protocol message with a whole network realm if the private user identification is not available; transmitting the second Diameter Protocol message from the first network element to a second network element; performing a second subscriber locator function by the second network element to determine a second home subscriber service (HSS) element to which the second Diameter Protocol message should be sent; populating by the second network element a Redirect-Host attribute value pair with information relating to the second home subscriber service (HSS) element; and, transmitting the second message back to the first network element and to the second home subscriber service (HSS) element if the second home subscriber service (HSS) element is not the second network element.