Inter-domain call routing
AssigneeBlackBerry Limited
InventorKaniz Mahdi
Life of this patent
Estimating the term…
Abstract
The present invention provides for routing calls between disparate domains, such as a circuit-switched subsystem and a multimedia subsystem. When a user element is homed in a first domain and roaming in a second domain, an incoming call will arrive at a gateway node in the first domain. As a result, a message identifying the user element and indicating that an incoming call has been received at first gateway node for the first domain is sent to a continuity control function (CCF) residing in the multimedia subsystem. The CCF will create and effect delivery of an inter-domain routing number to the first gateway node. The inter-domain routing number is used by the first gateway node to route the call to the second domain. The inter-domain routing number may be associated with a second gateway node of the second domain.
Claims20
A method for routing an incoming call, the method comprising:
- receiving in a first domain, by a continuity control function (CCF) executing on an application server from a serving call session control function (S-CSCF), an invite message identifying a user element;
- terminating the invite message on a first signaling leg in the first domain by the CCF functioning as a Back-to-Back User Agent (B2BUA) on the application server;
- sending, by the CCF to a home location register (HLR), a first message identifying the user element and indicating that an incoming call intended for the user element has been routed to the CCF in the first domain;
- receiving, by the CCF, an inter-domain routing number for the CCF to use to route the incoming call into a second domain, wherein the inter-domain routing number identifies a visited mobile switching center (VMSC) in the second domain;
- and
- sending, by the CCF functioning as the B2BUA on the application server, a second message on a second signaling leg, where the second message is used to route the incoming call to the second domain using the interdomain routing number that identifies the VMSC, obtained in the step of receiving the interdomain routing number, wherein the second domain is a circuit-switched subsystem and the first domain is a multimedia subsystem.
An application server, comprising:
- a processor configured to execute a continuity control function (CCF) configured to:
- receive an invite message in a first domain from a serving call session control function (S-CSCF), the invite message identifying a user element;
- terminate the invite message on a first signaling leg in the first domain, wherein the CCF is configured to function as a Back-to-Back User Agent (B2BUA) to terminate the invite message on the first signaling leg;
- send, by the CCF to a home location register (HLR), a first message identifying the user element and indicating that an incoming call intended for the user element has been routed to the CCF in the first domain;
- receive, by the CCF, an inter-domain routing number for the CCF to use to route the incoming call into a second domain, wherein the inter-domain routing number identifies a visited mobile switching center (VMSC) in the second domain;
- and
- send, by the CCF functioning as the B2BUA on the application server a second message on a second signaling leg, where the second message is at least partially used to route the incoming call to the second domain using the interdomain routing number that identifies the VMSC, obtained in the step of receiving the interdomain routing number, wherein the second domain is a circuit-switched subsystem and the first domain is a multimedia subsystem.
Dependencies are inferred from the claim text.