Section: Annex E (Normative): TWAN mapping table between GTPv2 S2a Cause and non-3GPP access Cause values
Content: The TWAN initiates session establishment requests or mobility management requests towards the PGW. If this operation is not successful, there are several possible cause codes, which need to be mapped to the appropriate cause codes over non-3GPP access to the UE. The TWAN should map these cause codes as defined in Table E.1, Table E.2, Table E.3 and Table E.4. Table E.1: Mapping from GTPv2 S2a to non-3GPP access Cause values – Rejection indication from PGW Table E.2: Mapping from GTPv2 S2a to non-3GPP access Cause values – Acceptance indication from PGW Table E.3: Mapping from GTPv2 S2a to WLCP Cause values – Indication in request from PGW Table E.4: Mapping from WLCP to GTP Cause values – Rejection indication from TWAN