The present document defines the stage-3 protocol description for several reference points for the non-3GPP access in EPS. The present document is applicable to: The SWa reference point between an un-trusted non-3GPP IP access and the 3GPP AAA Server/Proxy. The STa reference point between a trusted non-3GPP IP access and the 3GPP AAA Server/Proxy. The SWd reference point between the 3GPP AAA Proxy and 3GPP AAA Server. The SWx reference point between the 3GPP AAA Server and the HSS. The S6b reference point between the 3GPP AAA Server/Proxy and the PDN GW. The H2 reference point between the 3GPP AAA Server and the HA. The SWm reference point between the 3GPP AAA Server/Proxy and the ePDG.