PS core network

The PS core network consists of two parts, the traditional General Packet Radio Service (GPRS) core network and the new Evolved Packet System (EPS) core network. The PS core network connects mobile subscribers to Packet Data Networks (PDNs) such as the Internet, corporate networks or operator services networks. a functional overview of the PS core network.

Logical entities and interfaces are shown in black and form a 2G/3G network, while the blue boxes and lines in Figure  show the LTE/EPC related parts. The LTE/EPC network can be regarded as an extension and evolution of existing 2G/3G networks. From a node implementation perspective, there is no strict border between the two networks. The corresponding logical entities of GPRS and EPS networks can be deployed concurrently in Ericsson PS core nodes, such as the SGSN-MME and EPG; these are marked in red. In addition, Ericsson GPRS nodes can be upgraded with EPC functionality by software only.

Network evolution is supported by the following Ericsson PS core products.

·         Serving GPRS Support Node - Mobility Management Entity (SGSN-MME) - The SGSN-MME acts either as the SGSN for GPRS core network, or as the MME for EPC network, or as a combination of both SGSN and MME.

·         Evolved Packet Gateway (EPG) - EPG allows simultaneous combination of the Gateway GPRS Support Node (GGSN), Serving Gateway (SGW), and PDN Gateway (PGW) functions on one physical node.

As part of the evolution of EPC, the Policy and Charging Control (PCC) architecture, shown in Figure 3, is mainly provided by the Policy and Charging Rules Function (PCRF), the Policy and Charging Enforcement Function (PCEF), the Application Function (AF) and the Online/Offline Charging System (OCS and OFCS) entities. Ericsson Service-Aware Charging and Control (SACC) solution provides complete and validated PCC functions based on the following Ericsson PS core products:

·         Service Aware Policy Controller (SAPC) - SAPC implements the PCRF function as described by the 3GPP PCC standards.

·         Service Aware Support Node (SASN) - SASN is a standalone PCEF entity and can be deployed on the Gi/SGi interface between the EPG and Internet Security and Gateway functions.

·         EPG - as a combined gateway platform for GGSN, SGW and PGW, the EPG contains a PCEF function for PCC architecture. The service awareness function in the SACC Solution is based on an advanced packet inspection available integrated in EPG or  standalone in SASN.