correlationID  IE 

The Correlation ID parameter contains the SIP-URI-B identifying the (MSISDN-less) destination user. SIP-URI-A and HLR-ID shall be absent from this parameter. The Correlation ID indicates by its presence that the request is sent in the context of MSISDN-less SMS delivery in IMS (see 3GPP TS 23.204). When received, the HLR shall return the IP-SM-GW number and shall not forward the request to an IP-SM-GW.

Reference: TS 29.002-f30   View