Packet Zone

For the network layout there are several zones that can be assigned within
a PDSN network. These zones are referred to as packet zones and should be
distributed along the same deployment and logical assignment method
used for assigning BSCs. In other words, every BTS connected to a particular
BSC should have the same packet zone assigned to it. However, it is possible
to have several BSCs residing in the same packet zone, but it is
recommended that a separate packet zone be assigned to every BSC.