Patent ID: 8861508
Filing Date: 2014-10-14
Classification: H04L

Abstract:
1. A method of routing a call setup request from an originating network to a destination serving node in a destination Internet protocol Multimedia Subsystem (“IMS”) network, the method comprising: a) a switching node in the originating network receiving the call setup request, in the form of a Session Initiation Protocol (SIP) Invite, having a destination number indicating a destination subscriber receiving service from the destination serving node; b) the switching node sending a query comprising the destination number to a number conversion database node within the originating network for destination routing information; c) the number conversion database node retrieving destination serving node information relating to the destination subscriber from subscriber information relating to the destination IMS network in response to the query for destination routing information from the switching node, the destination serving node information comprising: d) the number conversion database node replying to the switching node with destination routing information comprising the destination serving node address and the SIP URI; and e) the switching node routing the SIP Invite directly to the destination serving node using the destination serving node address and the SIP URI.