The roadwarrior carol sets up a connection to gateway moon. At the outset the gateway authenticates itself to the client by sending an IKEv2 digital signature accompanied by an X.509 certificate.
Next carol uses the MD5 (EAP-MD5) method of the Extensible Authentication Protocol to authenticate herself. The gateway forwards all EAP messages to the RADIUS server alice. In addition to her IKEv2 identitycarol@strongswan.org, roadwarrior carol uses the EAP identity carol.