Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

...

The E-CSCF functionality can be used when SBC acts as Proxy Call Session Control Function (P-CSCF). Therefore, the SBC acts as a combined P-CSCF and E-CSCF (P+E-CSCF).

...

  • Receives an emergency session establishment request from a P CSCF or an S-CSCF.
  • If location information is not included in the emergency request or additional location information is required, the E CSCF requests the LRF to retrieve location information.
  • If required, the E-CSCF requests the LRF to validate the location information included by the UE.
  • Determines or queries the LRF for the proper routing information/PSAP destination.
  • Route emergency session establishment requests to an appropriate destination including anonymous session establishment requests.
  • Subject to local regulation, the E-CSCF may send the contents of the P-asserted ID or UE identification to the LRF.
  • Based on operator policy, the E-CSCF may route the emergency IMS call to ECS for further call process.
  • For supporting SRVCC, the E-CSCF forwards the session establishment request to the EATF in the serving IMS network for anchoring.

Deployment Scenario

The SBC acting as an E-CSCF can interact with the 3rd a third-party LRF. An LRF is responsible for retrieving the location information of the UE that has initiated an IMS emergency session. An LRF can interact with a location service and to manage ESQK allocation and management. The ESQK is used by the PSAP to query the LRF for location information and optionally a callback number. Information provided by the LRF to the E‑CSCF includes the routing information to the appropriate PSAP and other parameters necessary for emergency services, which is forwarded to the PSAP by SBC as E-CSCF.

In some Some regions, for example in the North American region, it may be a requirement such as North America, may require the ability to provide the PSAP with an accurate initial location estimate for the UE and possibly to provide an accurate updated location estimate for the UE if requested by the PSAP. When this requirement exists. In such cases, the LRF may store stores a record of the emergency session including all information provided by the E‑CSCF and shall only release this , and releases the record when informed by the E‑CSCF that the emergency session has terminated. The information provided by the LRF to the E‑CSCF (for example, ESQK) then includes correlation information identifying both the LRF and the emergency session record in the LRF. This correlation information is transferred to the PSAP by the SBC as E-CSCF during session establishment. The PSAP may can use this information to request an initial location estimate from the LRF and/or to request an updated location estimate.

...

Anchor
ZoneConfiguration(TowardsPeerinExternal)
ZoneConfiguration(TowardsPeerinExternal)
Zone Configuration (Towards Peer in External)

...

IBCF (Towards Peer IBCF/IPX)

Common Configuration

...