E.3 Enhanced caller data

33.1273GPPLawful Interception (LI) architecture and functionsRelease 18TS

E.3.1 General

Two approaches, namely Rich Call Data (RCD) and eCNAM (Enhanced Calling Name) build on STIR/SHAKEN to provide additional caller information rendered to the callee during alerting to encourage the callee to answer the session.

E.3.2 RCD

RCD is described in an IETF draft draft-ietf-stir-passport-rcd-12 [42]. RCD is of two main categories. The first data is a more traditional set of information about a caller associated with "display-name", typically a textual description of the caller in the SIP INVITE. The second category is a set of RCD that is defined as part of the jCard (JSON format for vCard) as specified in RFC 7095 [43]. RCD is inserted in the SIP Identity header token and is digitally signed. If a session is not authenticated and signed then RCD cannot be used. While RCD can be provided by an originating authentication service, an intermediary in the session path could also acquire RCD by querying a third-party service. Such a service effectively acts as a STIR authentication service, generating its own Identity token including RCD, and that token could be attached to a SIP session by either the originating or terminating side.

E.3.3 eCNAM

The Enhanced Calling Name (eCNAM) service defined in TS 24.196 [44] provides the terminating user with a name that identifies the originating user, and metadata about that originating user (e.g. address, language, etc.), like with RCD. eCNAM data is managed by the originating network and stored in an authoritative database. To enable the terminating network to retrieve eCNAM data, the terminating service provider queries the database using the calling telephone number as the key, to obtain calling display name and other metadata.

In both RCD and eCNAM the terminating network shall populate the received name and received metadata elements in appropriate SIP headers in the INVITE request being forwarded to the terminating UE.