3Com SuperStack 3 NBX Administrator's Manual page 89

Figure 28 Multi-site network using Virtual Tie Lines
Chicago
NBX System
Extensions
1000 – 1999
In the sample network shown in Figure 28, each site is set up to use a
unique range of telephone extensions. The dial plan on each of the
systems is configured so that whenever a call is made to an extension not
located at the local site, the NBX system sets up a VTL connection to the
appropriate site.
To make a call to a user in Dallas, a user in Chicago dials a Dallas
extension (3000 through 3999). The dial plan on the Chicago NBX system
is configured to set up the necessary VTL connection to the Dallas NBX
system, and then to the extension at that site.
See "Dial Plan Configuration" later in this chapter for further information
on how to set up VTLs in the dial plan.
Overview of Virtual Tie Lines
WAN
Dallas
NBX System
Extensions
3000 – 3999
89
Atlanta
NBX System
Extensions
2000 – 2999