Key CN Enhancements The two key enhancements in the core network are - Next Generation HLR (ngHLR) and the second important element is Generic Authentication Architecture. The consolidation of IMS specifications in the form Common IMS are also highlighted in the section. 8.2.5.1 ngHLR The ngHLR technology is not associated with any specific 3GPP release but rather it is an infrastructure vendors' and operators' driven initiative for improving the performance of HLR. The initiative stated the Next Generation Mobile Communications Ecosystem Core Network Home Agent INTERNET IP backbone Foreign Agent Figure 8.13 MBWA core network ngHLR should be subscriber centric and IP-based. It should also be based on an open and distributed architecture and support different access techniques. 8.2.5.1.1 Overview and System Architecture The ngHLR design is based on a highly distributed architecture in which HLR application (service logic) and the HLR data are logically (and often physically) separated. Figure 8.14 shows the service-level view of the ngHLR architecture, where the subscriber and service data associated with the HLR has been decoupled from the application logic and resides within a Central Database. The Central Database can be shared for both CS and PS services. BEFORE AFTER Provisioning Provisioning Service De-silo the data Logic Logic Logic Logic Logic Service Figure 8.14 ngHLR architecture Core Networks and Operations Support Systems The distributed architecture consists of front-end and back-end systems. The front-end (FE) systems implement application logic whereas back-end (BE) systems hold subscribers data. The architectural separation of data (BE/Data Base) and signaling (FE/Call Control) means that there is no need to add unnecessary subscriber capacity in order to increase the signaling capacity, and vice versa. By varying the numbers of HLR FEs, deployments can encompass transaction rates from 100s to 1000s per second. By varying the numbers of HLR Back End nodes, deployments can easily range from less tha