Comtech EF Data CDD-56X Series Vipersat - Manual (Page 70)

Vipersat Configuration MN/22137, rev 1
3-36 Vipersat CDD-56X Series User Guide
Typically the default value will be optimum, but if there may be a larger band-
width requirement after the switch, the percent allocation value can be
increased. In choosing a value for this allocation, future bandwidth require-
ments for the channel must be balanced against efficient bandwidth utilization.
Keep Alive Timer for Carrier Inhibit
This parameter applies to a Hub unit only. Note that, although this menu item
also appears for a Remote unit, it does not apply to a switched demod unit at a
remote site.
The Keep Alive Timer for Carrier Inhibit parameter provides a fixed setting
that can be specified for the keep alive message sent to the Remotes from the
Hub. This provides an alternate to the burst map which is variable and may
become excessively long in certain applications. An example of this is a burst
map containing a large number (up to 100) of remotes running in ECM mode
where the burst period exceeds the Remote carrier inhibit timer.
When implemented, this parameter is set at either the TDM outbound unit or a
switched demod, not at the STDMA Controller, in order to prevent a problem
should the burst controller be rebooted.
Enter C at the command prompt in the Auto Switching screen to display the
dialog shown in figure 3-47.
Figure 3-47 Keep Alive Timer for Carrier Inhibit prompt
Note that this timer setting should be at least three times faster (shorter in dura-
tion) than the timer setting at the Remote(s) to ensure that network links are
maintained.
Hitless Switching Parameters
Unless inherent delays in configuring both ends of a satellite bandwidth link
during dynamic switching are accounted for, transmitted data may be lost
during the transition. The time for a switch command to be sent across the satel-
lite link (~ 250 ms), the command processing time, as well as receiver acquisi-
tion time must be considered. The Vipersat Hitless Switching feature provides