Comtech EF Data VMS v3.12.x Vipersat - Manual (Page 247)

Chapter 4 - Configuring Network Modems 4-29
MN/22156, rev 12 Network
matches a particular route, the ModCod specified for the group to which the
Remote belongs is immediately known and is applied.
The determination of what ModCod should be assigned to a group is by the link
budget calculations; a combination of distance from the satellite, the satellite's
G/T performance, dish size, and environmental conditions. The grouping should
be based on an equal distribution or fairness within the assigned group. Depend-
ing on the use of IP addressing plans, the groups may be governed by the
customer.
Each group is assigned a ModCod that is the maximum ModCod that the pack-
ets can go out in, but the packets could go out in a lower ModCod when the
VMS determines—through its optimized scheduler algorithm—a better utiliza-
tion of the bandwidth and oversubscription conditions.
This shifting of ModCod assignments at the Hub requires that the ModCod
selection for the CDM-840 Remote demodulator be set for Auto. See the
section “Devices | Demod” on page 4-64.
A maximum of six unique ModCods can be specified for use by a CDM-800 for
the TDM outbound carrier. The same ModCod can be assigned to multiple
groups.
Figure 4-19 Quality of Service Groups dialog