Systems and methods for emergency call route failover
A system and method for performing an emergency call route failover between an Emergency Call Session Control Function (E-CSCF) and multi-homed remote end-point functions such as Border Gateway Control Function(BGCF)/Media Gateway Control Function (MGCF) or Interconnection Border Control Function (IBCF) in an Internet Protocol Multimedia Subsystem (IMS) uses Session Initiation Protocol (SIP) and/or Domain Name System (DNS) methods. The E-CSCF and/or a DNS server monitors the availability of the remote end-points to create a peer list of route options. The E-CSCF or the DNS server selects a route option from the peer list to route an emergency call to an appropriate Public Safety Answering Point (PSAP). In the event that the route option fails, the E-CSCF fails over to the next available route option to route the emergency call.
1. A method for performing an emergency call route failover within a telecommunications network, the method comprising:
receiving, from an Emergency Call Control Session Function (E-CSCF), a Domain Name System (DNS) request to determine a routing option for routing an emergency call;
initiating at least one health check request towards each of multiple gateway nodes to monitor health of the multiple gateway nodes;
receiving, from at least one of the multiple gateway nodes, one or more health check responses;
based on the one or more health check responses, identifying one or more gateway nodes from the multiple gateway nodes,
wherein the one or more gateway nodes are identified as being available to receive the emergency call, as being unavailable to receive the emergency call, or both;
selecting a gateway node to receive the emergency call; and
providing the selected gateway node as a response to the DNS request.
2. The method of claim 1 further comprising:
determining that the emergency call is associated with a gateway node of a specific type; and
selecting the available gateway nodes of the specific type to dynamically create a list of available nodes
wherein the specific type is one of: a Border Gateway Control Function (BGCF), Media Gateway Control Function (MGCF) or an Interconnection Border Control Function (IBCF).
3. The method of claim 1 further comprising:
receiving a Session Initiation Protocol (SIP) INVITE request associated with the emergency call;
initiating a SIP INVITE request associated with the emergency call towards the selected gateway node to deliver the emergency call to a public safety answering point (PSAP).
4. The method of claim 1 , wherein the E-CSCF is further configured to:
detect a failover condition when the selected gateway node fails to respond within a time period; and
select an alternate gateway node, in response to the failover condition.
5. The method of claim 1 further comprising:
providing routing information that includes Emergency Service Routing Key (ESRK) that is used by a PSTN PSAP or an IP PSAP to request location information associated with the emergency call.
6. The method of claim 1 , wherein the multiple gateway nodes are Media Gateway Control Function (MGCF) nodes when the emergency network has Time Division Multiplex (TDM) connectivity, and wherein the multiple gateway nodes are Interconnection Border Control Function (IBCF) nodes when the emergency network has Internet Protocol (IP) connectivity.
7. At least one machine-readable medium, excluding transitory signals, having stored thereon instructions, which when executed by at least one machine, analyzes nodes for use with emergency call routing in a telecommunications network causing the at least one machine to:
receive, from an Emergency Call Control Session Function (E-CSCF), a Domain Name System (DNS) request to determine a routing option for routing an emergency call;
initiate at least one health check request towards each of multiple gateway nodes to monitor health of the multiple gateway nodes;
receive, from at least one of the multiple gateway nodes, one or more health check responses;
based on the one or more health check responses, identify one or more gateway nodes from the multiple gateway nodes,
wherein the one or more gateway nodes are identified as being available to receive the emergency call, as being unavailable to receive the emergency call, or both;
based on the identification, select a gateway node to receive the emergency call; and
provide the selected gateway node as a response to the DNS request.
8. The at least one machine-readable medium of claim 7 , wherein the instructions, when executed, further cause the at least one machine to:
determine that the emergency call is associated with a gateway node of a specific type; and
select the available gateway nodes of the specific type to dynamically create a list of available nodes
wherein the specific type is one of: a Border Gateway Control Function (BGCF), Media Gateway Control Function (MGCF) or an Interconnection Border Control Function (IBCF).
9. The at least one machine-readable medium of claim 7 , wherein the instructions, when executed, further cause the at least one machine to:
receive a Session Initiation Protocol (SIP) INVITE request associated with the emergency call;
initiate a SIP INVITE request associated with the emergency call towards the selected gateway node to deliver the emergency call to a public safety answering point (PSAP).
10. The at least one machine-readable medium of claim 7 , wherein the E-CSCF is configured to:
detect a failover condition when the selected gateway node fails to respond within a time period; and
select an alternate gateway node, in response to the failover condition.
11. The at least one machine-readable medium of claim 7 , wherein the instructions, when executed, further cause the at least one machine to:
provide routing information that includes Emergency Service Routing Key (ESRK) that is used by a PSTN PSAP or an IP PSAP to request location information associated with the emergency call.
12. The at least one machine-readable medium of claim 7 , wherein the multiple gateway nodes are Media Gateway Control Function (MGCF) nodes when the emergency network has Time Division Multiplex (TDM) connectivity, and wherein the multiple gateway nodes are Interconnection Border Control Function (IBCF) nodes when the emergency network has Internet Protocol (IP) connectivity.
13. The at least one machine-readable medium of claim 7 , wherein the response to the DNS request includes an IP address of the selected gateway node.
14. A system for performing an emergency call route failover within a telecommunications network, the system comprising:
at least one telecommunications server coupled to the telecommunications network, wherein the telecommunications server includes a processor to perform a method, the method comprising:
receiving, from an Emergency Call Control Session Function (E-CSCF), a Domain Name System (DNS) request to determine a routing option for routing an emergency call;
initiating at least one health check request towards each of multiple gateway nodes to monitor health of the multiple gateway nodes;
receiving, from at least one of the multiple gateway nodes, one or more health check responses;
based on the one or more health check responses, identifying one or more gateway nodes from the multiple gateway nodes,
wherein the one or more gateway nodes are identified as being available to receive the emergency call, as being unavailable to receive the emergency call, or both;
based on the identification, selecting a gateway node to receive the emergency call; and
providing the selected gateway node as a response to the DNS request.
15. The system of claim 14 , wherein the health check responses comprises at least one of variables, data node-specific information collected by SNMP agents, acknowledgement to the health check requests, error responses, or any combination thereof.
16. The system of claim 14 , wherein the method further comprises:
updating a peer list of BGCF/MGCF nodes and/or a peer list of IBCF nodes based on the health check responses,
wherein nodes that respond with an error are marked as being down or unavailable, fail to respond, or are otherwise unusable by the system, and
wherein nodes that respond with acknowledgement and/or other data are marked as being up or available.
17. The system of claim 14 , wherein the selection of the gateway node to receive the emergency call is based on round-robin scheduling, geographical scheduling, area code/Automatic Number Identification (“ANI”), or any combination thereof.
18. The system of claim 14 , wherein the response to the DNS request includes an IP address of the selected gateway node.
19. The system of claim 14 , wherein the method further comprises providing routing information that includes Emergency Service Routing Key (ESRK) that is used by a PSTN PSAP or an IP PSAP to request location information associated with the emergency call.
20. The system of claim 14 , wherein the multiple gateway nodes are Media Gateway Control Function (MGCF) nodes when the emergency network has Time Division Multiplex (TDM) connectivity, and wherein the multiple gateway nodes are Interconnection Border Control Function (IBCF) nodes when the emergency network has Internet Protocol (IP) connectivity.