works. Next Generation Mobile Communications Ecosystem User Data Signaling HSPA Device WCDMA Device Figure 8.5 3GPP Release 7 direct tunnel architecture 8.2.1.6 Release 8 Release 8 brings the most significant change to the CN architecture since the inception of mobile tele- phony. First the EPC (Evolved Packet Core) will only support packet switched traffic and second in a most basic sense, the CN architecture consists of only one node in the user plane, core network Gateway (GW). 8.2.1.6.1 Objectives The objective of the SAE (System Architecture Evolution) or EPC is to build the specifications for a packet optimized system that is designed to support multiple radio access technologies. This system designed for a packet switched domain with the assumption that voice services are supported within this domain. The main objectives of the SAE are as follows: Overall architecture impacts stemming from requirements coming out of RANs LTE work. Overall architecture impacts stemming from the SA1's (Services Working Group) all-IP work. Overall architecture aspects of supporting mobility between heterogeneous access networks. Core Networks and Operations Support Systems GERAN GPRS Core UTRAN Serv. Evolved RAN Anchor Anchor (IMS, etc...) Evolved 3GPP IP Packet Core Access Trusted non 3GPP IP Access Access NW * Colour coding: red indicates new functional element / inteface Figure 8.6 Logical high level architecture for the evolved system. Reproduced with permission from C 2008 3GPP 8.2.1.6.2 System Architecture Figure 8.6 shows the possible evolved system architecture [12] that consists of Evolved RAN, EPC (Evolved Packet Core Network), IMS and hooks to 3GPP and non-3GPP access technologies. A brief definition of these elements is as follows: The Evolved RAN will include eNodeBs (evolved base transceiver stations) that interface with user equipments and supports LTE air interface (E-UTRAN). The EPC includes MME/UPE functionalities and 3GPP and SAE anchor points. The Mobile Management Entity (MME) that supports user equipment