This chapter introduces the Network Location Register (NLR) and provides information about the system hardware and software platform requirements. It contains the following sections:
•Network Location Register Description
The P25 Network Location Register (NLR) stores data about subscribers and groups operating within a single Radio Frequency Subsystem (RFSS). It can function as a traditional Home Location Register (HLR) for an APCO P25 system as well as a Visitor Location Register (VLR) for roaming subscribers, that is, those subscribers that are not declared ("homed") at this RFSS.
Network Location Register Description
The NLR runs on a Commercial Off-The-Shelf (COTS) PC. All interfaces are IP-based, so no special cables or hardware are required. The NLR can also be part of a high availability or disaster recovery node within the core network.
Figure 1-1 shows an example of a multiple RFSS, consisting of one or more base stations and a central RFSS Network Controller along with the NLR.
Figure 1-1 Typical Multi Site RFSS
The NLR requires no special equipment to install, as it is a software application that runs on any COTS PC. The NLR will usually plug directly into a local network switch for its network interface. If the NLR is co-hosted with the RNC, it is possible to share a single physical network connection by allocating the primary IP for the RNC and assigning a second virtual IP interface for the NIF process.
The single supported operating system for the NLR is IPICS OS 4.5. Cisco provides an installer that installs the ISSI Gateway software on IPICS OS. The NLR is included on that software installation.