Patent ID: 9654964
Date: 2017-05-16
CPC Classifications: H04L,H04W

Claim:
1. A method comprising: receiving, by a processor at a CSCF (Call Session Control Function) portion of a home network in which a mobile station is subscribed, an IMS (IP Multimedia Subsystem) registration request from the mobile station via a visited network to which the mobile station is attached; establishing an SIP (Session Initiation Protocol) session between the mobile station and the CSCF in response to the received IMS registration request; receiving, at the CSCF, a first SIP INVITE message from the mobile station during the SIP session, wherein the first SIP INVITE requests use of a service; obtaining an identifier for the visited network; obtaining, in response to receiving the first SIP INVITE message, a first roaming policy based on the identifier for the visited network; determining whether the first SIP INVITE message is acceptable based on the obtained first roaming policy and the service requested by the first SIP INVITE message; sending a response for the first SIP INVITE message to the mobile station, wherein the response is based on the determination whether the first SIP INVITE message is acceptable; obtaining, at the CSCF and in response to receiving the first SIP INVITE message, a second roaming policy based on the identifier for the visited network; determining, by the CSCF, that the first SIP INVITE message is acceptable based on the second roaming policy; sending, in response to the determination that the first SIP INVITE message is acceptable based on the second roaming policy, a second SIP INVITE message, based on the first SIP INVITE message, from the CSCF to an AS (Application Server) included in the home network; determining, in response to receiving the second SIP INVITE message at the AS, a subscriber identifier or subscriber type for the mobile station; and obtaining the first roaming policy based on the identifier for the visited network and the determined subscriber identifier or subscriber type; wherein the determining whether the first SIP INVITE message is acceptable based on the obtained first roaming policy is performed by the AS.