IMS emergency call routing techniques
IMS emergency call routing techniques are described. In one embodiment, for example, an apparatus may comprise at least one memory and logic for a P-CSCF node, at least a portion of the logic comprised in circuitry coupled to the at least one memory, the logic to cause the P-CSCF node to receive an SIP INVITE message from a roaming UE, the SIP INVITE message associated with an attempt to place an emergency call via an unauthenticated IMS session, the logic to cause the P-CSCF node to obtain a PSAP callback number for the UE from a PCRF node via an Rx interface, identify a PSAP callback parameter for the UE based on the PSAP callback number, insert the PSAP callback parameter into the SIP INVITE message, and forward the SIP INVITE message to a PSAP. Other embodiments are described and claimed.
1. An apparatus, comprising:
processing circuitry; and
non-transitory computer-readable storage media to store instructions that, when executed by the processing circuitry, cause a proxy call session control function (P-CSCF) of an internet protocol multimedia subsystem (IMS) of a public land mobile network (PLMN) to:
determine a callback parameter for user equipment (UE) roaming within the PLMN based on a mobile station international subscriber directory number (MSISDN) comprised in a message received from a policy and charging rules function (PCRF) node during an Rx session establishment procedure;
insert the callback parameter into a received session initiation protocol (SIP) INVITE message associated with an attempt on part of the UE to place an emergency call via an unauthenticated IMS session, the received SIP INVITE message to comprise an anonymous user parameter; and
forward the SIP INVITE message to a public safety answering point (PSAP).
2. The apparatus of claim 1 , the callback parameter to comprise a telephone uniform resource identifier (TEL URI).
3. The apparatus of claim 1 , the non-transitory computer-readable storage media to store instructions that, when executed by the processing circuitry, cause the P-CSCF to initiate the Rx session establishment procedure based on receipt of an SIP REGISTER message from the UE.
4. The apparatus of claim 3 , the non-transitory computer-readable storage media to store instructions that, when executed by the processing circuitry, cause the P-CSCF to determine, based on the SIP REGISTER message, that no network-to-network interface (NNI) exists between the IMS of the PLMN and an IMS of a home public land mobile network (HPLMN) of the UE.
5. The apparatus of claim 3 , the SIP REGISTER message to comprise an SIP uniform resource identifier (SIP URI) of the UE.
6. The apparatus of claim 1 , the non-transitory computer-readable storage media to store instructions that, when executed by the processing circuitry, cause the P-CSCF to initiate the Rx session establishment procedure by sending an AA-Request command to the PCRF node via an Rx interface.
7. The apparatus of claim 6 , the AA-Request command to comprise an indication of an internet protocol version 4 (IPv4) address of the UE.
8. The apparatus of claim 7 , the AA-Request command to comprise a Framed-IP-Address attribute-value pair (AVP) indicating the IPv4 address of the UE.
9. The apparatus of claim 8 , the AA-Request command to comprise an IP-Domain-Id value associated with the IPv4 address of the UE.
10. The apparatus of claim 6 , the AA-Request command to comprise an indication of an internet protocol version 6 (IPv6) prefix associated with the UE.
11. The apparatus of claim 10 , the AA-Request command to comprise a Framed-Ipv6-Prefix attribute-value pair (AVP) indicating the IPv6 prefix associated with the UE.
12. The apparatus of claim 6 , the message received from the PCRF node to comprise an AA-Answer command received via the Rx interface.
13. Non-transitory computer-readable storage media having stored thereon instructions that, in response to being executed by processing circuitry of a computing device, cause a proxy call session control function (P-CSCF) of an internet protocol multimedia subsystem (IMS) of a public land mobile network (PLMN) to:
determine a callback parameter for user equipment (UE) roaming within the PLMN based on a callback number comprised in a message received from a policy and charging rules function (PCRF) node via an Rx interface;
insert the callback parameter into a received session initiation protocol (SIP) INVITE message comprising an anonymous user parameter indicating an attempt by the UE to place an emergency call via an unauthenticated IMS session; and
forward the SIP INVITE message to a public safety answering point (PSAP) of the PLMN.
14. The non-transitory computer-readable storage media of claim 13 , the callback number to comprise a mobile station international subscriber directory number (MSISDN) associated with the UE.
15. The non-transitory computer-readable storage media of claim 13 , the callback parameter to comprise a telephone uniform resource identifier (TEL URI).
16. The non-transitory computer-readable storage media of claim 13 , the message received from the PCRF node to comprise an AA-Answer command receiving during an Rx session establishment procedure.
17. The non-transitory computer-readable storage media of claim 16 , having stored thereon instructions that, in response to being executed by processing circuitry of the computing device, cause the P-CSCF to initiate the Rx session establishment procedure by sending an AA-Request command to the PCRF node via the Rx interface.
18. The non-transitory computer-readable storage media of claim 17 , the AA-Request command to comprise an indication of an internet protocol version 4 (IPv4) address of the UE.
19. The non-transitory computer-readable storage media of claim 18 , the AA-Request command to comprise a Framed-IP-Address attribute-value pair (AVP) indicating the IPv4 address of the UE.
20. The non-transitory computer-readable storage media of claim 17 , the AA-Request command to comprise an indication of an internet protocol version 6 (IPv6) prefix associated with the UE.
21. The non-transitory computer-readable storage media of claim 20 , the AA-Request command to comprise a Framed-Ipv6-Prefix attribute-value pair (AVP) indicating the IPv6 prefix associated with the UE.
22. The non-transitory computer-readable storage media of claim 16 , having stored thereon instructions that, in response to being executed by processing circuitry of the computing device, cause the P-CSCF to initiate the Rx session establishment procedure based on receipt of an SIP REGISTER message from the UE.
23. The non-transitory computer-readable storage media of claim 22 , having stored thereon instructions that, in response to being executed by processing circuitry of the computing device, cause the P-CSCF to determine, based on the SIP REGISTER message, that no network-to-network interface (NNI) exists between the IMS of the PLMN and an IMS of a home public land mobile network (HPLMN) of the UE.
24. The non-transitory computer-readable storage media of claim 23 , the SIP REGISTER message to comprise an SIP uniform resource identifier (SIP URI) of the UE.