12 V IRTUAL CONNECTIONSThis chapter describes these elements of the system:■ Overview of Virtual Tie Lines■ TAPI Route Points■ TAPI SettingsFor more information about these topics and configuration procedures,see the online Help.Overview ofVirtual Tie LinesA Virtual Tie Line (VTL) provides a way to make calls between system sitesthat are separated geographically but tied together by a Wide AreaNetwork (WAN). VTLs are a licensed feature of the systems. V3000,V3001R, and V5000 systems can support up to 48 simultaneous VTLconnections. NBX 100 systems can support up to 8 simultaneous VTLconnectionsOn any system, you can use a VTL connection either for an incoming VTLcall from any site or for an outgoing VTL call to any site. A VTL connectionis not dedicated in the same way as a physical tie line, which alwaysconnects the same pair of sites. In the example in Figure 20, you can usethe VTLs on the Chicago system for any combination of incoming andoutgoing VTL calls to either Atlanta or Dallas.The system can reroute VTL calls that fail to reach their destination on thefirst attempt. For details, see “Call Rerouting for Virtual Tie Lines” onpage 341.■ You must configure the system for either IP On-the-Fly or Standard IPto use VTL connections to other systems.■ VTL connections are not available on a SIP-mode system.
