"This document provides user level descriptions and access network call flows designed toassist in the development of the interfaces that coincide with the Reference Points: ""A""@""Ater""@ ""Aquater""@ and ""Aquinter""@ as defined in the Network Reference Model (refer to[27])@ and Reference Points 48 and 27 as defined in Network Reference Model (refer to[34]). Refer to [14]~[17] for definitions of messages and timers used in this document."