When an HLR receives a request for authentication and ciphering data for a Mobile Subscriber and it does not hold the requested data, it requests it from the AuC via the H-interface, stores
it and delivers it to the VLR and SGSN and MME which need them to perform the security functions for a mobile station.
The protocol used to transfer the data over this interface is not standardized.
This is the reference point for signalling and user data transfer between UE and HA.
H1 may be transported over IP connectivity provided by I-WLAN or 3GPP access system.
The H1 should be a subset of S2c.
This reference point defines the interface between HA and 3GPP AAA infrastructure (3GPP AAA server
or 3GPP AAA proxy) and is used to transport authentication, authorization and charging-related
information in a secure manner.
This is the IP transport reference point to carry the end-to-end UE-HA signalling and user data between
Access Router and HA. Since there is no direct signalling messages between these two entities this is
simple IP transport reference point, which does not require additional specification.