Techniques for providing location data in emergency calls

An emergency call routing method, comprising:

• receiving a session initiation protocol (SIP) INVITE for an emergency call from a telephony endpoint associated with a telephone number serviced by a telecommunication service provider (TSP) SIP call server, the SIP INVITE message header including multiple location objects including:
• (i) a registered geo-coded address location object associated with the telephone number placing the emergency call, and (ii) a location object comprised of lat-long coordinates determined at the time the emergency call is placed;
• determining whether the registered geo-coded address and the lat-long coordinates are within a specified distance of one another;
• when the registered geo-coded address and the lat-long coordinates are within a specified distance of one another, using the geo-coded address as the location object when handling the emergency call;
• when the registered geo-coded address and the lat-long coordinates are not within a specified distance of one another, using the lat-long coordinates as the location object when handling the emergency call;
• determining a public safety answering point (PSAP) to route the emergency call based on location object;
• and
• when the PSAP is presence information data format location object (PIDF-Lo) capable:
• routing the emergency call to the PSAP with the PIDF-Lo;
• receiving a SIP acknowledgement from the PSAP;
• forwarding the SIP acknowledgement back to the telephony endpoint such that a media path may be created between the telephony endpoint and the PSAP.

At least one machine-readable non-transitory medium comprising a set of instructions executable on a computing device operating as a Voice-over Internet Protocol (VoIP) emergency call server to cause the computing device to route emergency calls by:

• receiving a session initiation protocol (SIP) INVITE for an emergency call from a telephony endpoint associated with a telephone number serviced by a telecommunication service provider (TSP) SIP call server, the SIP INVITE message header including multiple location objects including:
• (i) a registered geo-coded address location object associated with the telephone number placing the emergency call, and (ii) a location object comprised of lat-long coordinates determined at the time the emergency call is placed;
• determining whether the registered geo-coded address and the lat-long coordinates are within a specified distance of one another;
• when the registered geo-coded address and the lat-long coordinates are within a specified distance of one another, using the geo-coded address as the location object when handling the emergency call;
• when the registered geo-coded address and the lat-long coordinates are not within a specified distance of one another, using the lat-long coordinates as the location object when handling the emergency call;
• determining a public safety answering point (PSAP) to route the emergency call based on location object;
• and
• when the PSAP is presence information data format location object (PIDF-Lo) capable:
• routing the emergency call to the PSAP with the PIDF-Lo;
• receiving a SIP acknowledgement from the PSAP;
• forwarding the SIP acknowledgement back to the telephony endpoint such that a media path may be created between the telephony endpoint and the PSAP.

An emergency call routing system, comprising:

• a Voice-over Internet Protocol (VoIP) emergency call server configured to:
• receive a session initiation protocol (SIP) INVITE for an emergency call from a telephony endpoint associated with a telephone number serviced by a telecommunication service provider (TSP) SIP call server, the SIP INVITE message header including multiple location objects including:
• (i) a registered geo-coded address location object associated with the telephone number placing the emergency call, and (ii) a location object comprised of lat-long coordinates determined at the time the emergency call is placed;
• determine whether the registered geo-coded address and the lat-long coordinates are within a specified distance of one another;
• when the registered geo-coded address and the lat-long coordinates are within a specified distance of one another, use the geo-coded address as the location object when handling the emergency call;
• when the registered geo-coded address and the lat-long coordinates are not within a specified distance of one another, use the lat-long coordinates as the location object when handling the emergency call;
• determine a public safety answering point (PSAP) to route the emergency call based on location object;
• and
• when the PSAP is not presence information data format location object (PIDF-Lo) capable:
• convert the SIP_INVITE to a TDM_ESQK message that includes the determined PSAP;
• send the TDM_ESQK message to a selective router for routing to the determined PSAP;
• receive a TDM acknowledgement message from the PSAP by way of the selective router;
• convert the TDM acknowledgement message to a SIP acknowledgement;
• forward the SIP acknowledgement back to the telephony endpoint such that a media path may be created between the telephony endpoint and the PSAP.

An emergency call routing method, comprising:

• receiving a session initiation protocol (SIP) INVITE for an emergency call from a telephony endpoint associated with a telephone number serviced by a telecommunication service provider (TSP) SIP call server, the SIP INVITE message header including multiple location objects including:
• (i) a registered geo-coded address location object associated with the telephone number placing the emergency call, and (ii) a location object comprised of lat-long coordinates determined at the time the emergency call is placed;
• determining whether the registered geo-coded address and the lat-long coordinates are within a specified distance of one another;
• when the registered geo-coded address and the lat-long coordinates are within a specified distance of one another, using the geo-coded address as the location object when handling the emergency call;
• and
• when the registered geo-coded address and the lat-long coordinates are not within a specified distance of one another, using the lat-long coordinates as the location object when handling the emergency call;
• determining a public safety answering point (PSAP) to route the emergency call based on location object;
• and
• when the PSAP is not presence information data format location object (PIDF-Lo) capable:
• converting the SIP_INVITE to a TDM_ESQK message that includes the determined PSAP;
• sending the TDM_ESQK message to a selective router for routing to the determined PSAP;
• receiving a TDM acknowledgement message from the PSAP by way of the selective router;
• converting the TDM acknowledgement message to a SIP acknowledgement;
• forwarding the SIP acknowledgement back to the telephony endpoint such that a media path may be created between the telephony endpoint and the PSAP.

At least one machine-readable non-transitory medium comprising a set of instructions executable on a computing device operating as a Voice-over Internet Protocol (VoIP) emergency call server to cause the computing device to route emergency calls by:

• receiving a session initiation protocol (SIP) INVITE for an emergency call from a telephony endpoint associated with a telephone number serviced by a telecommunication service provider (TSP) SIP call server, the SIP INVITE message header including multiple location objects including:
• (i) a registered geo-coded address location object associated with the telephone number placing the emergency call, and (ii) a location object comprised of lat-long coordinates determined at the time the emergency call is placed;
• determining whether the registered geo-coded address and the lat-long coordinates are within a specified distance of one another;
• when the registered geo-coded address and the lat-long coordinates are within a specified distance of one another, using the geo-coded address as the location object when handling the emergency call;
• and
• when the registered geo-coded address and the lat-long coordinates are not within a specified distance of one another, using the lat-long coordinates as the location object when handling the emergency call;
• determining a public safety answering point (PSAP) to route the emergency call based on location object;
• and
• when the PSAP is not presence information data format location object (PIDF-Lo) capable:
• converting the SIP_INVITE to a TDM_ESQK message that includes the determined PSAP;
• sending the TDM_ESQK message to a selective router for routing to the determined PSAP;
• receiving a TDM acknowledgement message from the PSAP by way of the selective router;
• converting the TDM acknowledgement message to a SIP acknowledgement;
• forwarding the SIP acknowledgement back to the telephony endpoint such that a media path may be created between the telephony endpoint and the PSAP.