untrusted Non-3GPP access in LTE - how ePDG request for Qos rule to PCRF in PMIP

Question

If we look at the spec 23.402 v10.8 section-5.2 and 6.2.1 the BBERF(SGW/trusted non-3GPP access) creates a Gateway Control Session Establishment Procedure call before it sends Proxy Binding Update message to PGW for QoS rule request (PMIP varient S2b). Now for Untrusted Non-3GPP access attach procedure section 7.2.1 after authentication and authorization procedure ePDG does not creates Gateway Control Session Establishment Procedure call.So how ePDG will request for QoS rule to PCRF during attach??

Answer 1

There should be a missing step to describe Gateway Control Session Establishment Procedure prior to Proxy Binding Update, similar to the figures in section 6.2.1.