Comtech EF Data VMS v3.12.x Vipersat - Manual (Page 370)

Switching Out-of-Band Modems MN/22156, rev 12
7-14 VMS User Guide
setting that defines the ModCod. With SNMP controlled modems, the ModCod
must be preset from either the modem front panel, a console or Web session, or
from the VMS Parameter View.
Every channel has one managed device, and it can never be re-used by another
channel, neither for InBand nor OOB. However, unmanaged devices can be re-
used in other channels. Note, however, that the risk in using unmanaged devices
multiple times is that the operator can activate a channel where one or more of
the unmanaged devices are already in use, and the VMS will take them from the
active circuit.
There can be any number of channels defined for a custom circuit, as long as
there are enough devices/units to support the channels.
A site is chosen as the “owner” of the circuit, and this site must contain the
device(s) that is/are to be the managed device(s) for the channel(s) in the circuit.
As a general rule, the owner must be the site that has the transmitting unit/
device. One exception to this rule is the half duplex circuit that is set up between
just two sites; in this case, either the transmitting site can be the owner (with the
modulator as the managed device) or the receiving site can be the owner (with
the demodulator as the managed device). Note that, for a full duplex circuit,
either site can be chosen as the owner because there is just one unit at each site
involved, and they both transmit as well as receive.
Configuring OOB Circuits
A powerful feature that is provided for building the OOB circuits is the Out-of-
Band Circuit Creation Wizard. This tool presents a simple method for configur-
ing any of the three circuit types.
OBCM User Interface
Circuit configuration is performed from the VMS using ViperView. The circuits
can be viewed by hierarchy but must be created at a site, either Hub or Remote,
as shown in figure 7-10, below.