2.2 TIF Number Substitution Feature

Number substitution of both the Calling and Called Party provides customers the ability of supporting numbers outside their normal number range without having to upgrade all the nodes in the network. The TIF Number Substitution (TIF NS) feature, along with the Numbering Plan Processor (NPP) and the Triggerless ISUP Framework (TIF), provide the following capabilities:

• Called number substitution to change a Public DN into a Private DN
• Calling number substitution to change a Private DN into a Public DN

The TIF NS feature is built upon the services provided by TIF and NPP to support Number Portability lookup of both Calling Party and Called Party numbers for substitution.

TIF NS provides the following functions:

• Definition of feature-specific pre-NPP processing to be performed by TIF
• Service Action specification (including Service Action names and precedence)
• Service Action Handlers
• Feature-specific post-NPP processing, if needed