This document defines the stage 2 service description for emergency services in the IP Multimedia Core Network
Subsystem (IMS), including the elements necessary to support IP Multimedia (IM) emergency services.
ITU-T Recommendation I.130 [4] describes a three-stage method for characterisation of telecommunication services,
and ITU-T Recommendation Q.65 [3] defines stage 2 of the method.
This document covers also the Access Network aspects that are crucial for the provisioning of IMS emergency services.
Other 3GPP specifications that are related to the IMS emergency services are TS 23.228 [1] on IMS in general,
including fixed broadband access aspects, and TS 23.234 [7] describing 3GPP/WLAN Interworking and TS 23.271 [5]
that covers location services. TS 25.301 [6] contains an overall description of the UMTS Terrestrial Radio Access
Network.
GPRS functions for support of IMS emergency services are not defined in this version of the specification.
The emergency support in different IP-CANs is described in the Informative Annex E.