Additional IN Service Examples Two additional services are presented here to reinforce how IN operates in a real network context. The LNP service represents a government mandated service need | Additional IN Service Examples Two additional services are presented here to reinforce how IN operates in a real network context. The LNP service represents a government mandated service need while the PVN demonstrates a solution to a common business need. Both services can be implemented using any of the IN versions discussed in this chapter. Local Number Portability LNP The North American Local Number Portability Act of 1996 relies on IN technology to deliver number portability for subscriber numbers. Prior to LNP blocks of phone numbers were associated to specific exchanges. Routing of interexchange calls was based on the NPA-NXX portion of the called number. The NPA identifies a particular geographic region and the NXX identifies the particular exchange. The long-term goal of LNP is to associate the phone number with individual subscribers effectively removing the network node association and allowing subscribers to keep their numbers. This means that as users migrate throughout the network a particular SSP will eventually handle many different NPA-NXX combinations instead of just one or two. Number Portability is being rolled out in phases that are designated by three different types of portability Service Provider Portability Service Portability Location Portability Service Provider Portability is the first phase and is currently being implemented. It allows subscribers to choose a different service provider but remain within their local region. More specifically they must remain within their present rate center which is generally defined as a local geographic area of billing such as a Local Access Transport Area LATA . Service Portability gives the subscriber the ability to change types of service while keeping their same phone number. For example a basic telephone service subscriber can switch to ISDN service without changing numbers. Location Portability allows subscribers to change geographical regions and take their phone numbers with them. At this point
