Method and apparatus for implementing a plurality of numbering plans in a telecommunications network

Abstract

A method and apparatus are disclosed for implementing a plurality of numbering plans in a telecommunications network. A network can support a private numbering plan for identifying private lines, as well as conventional public numbering plans. An illustrative hybrid numbering plan has a generic format of NPA-PPP-EXTN. The NPA value is a geographic component, in a similar manner to the PSTN plan. The PPP value identifies private lines or trunks. The EXTN value carries either the dialed digits or the derived digits through the network to the terminating private line. The EXTN digits may be required by a destination PBX to route a call to a connected station or another PBX. A numbering plan flag differentiates each of the different numbering plans employed by a network, such as the private numbering plan and the public numbering plan, to establish a plurality of routing domains. Each node or switch uses the numbering plan flag to access the appropriate routing table and forward the call to the proper destination. The numbering plan flag can be configured to differentiate among each possible routing domain, for example, using multiple flags or multiple bits in a single flag. Calls can be completed to private lines, without assigning public telephone numbers to the private lines.