Comtech EF Data CDM-760, Installation And Operation Manual

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Ethernet Interface Operation Revision 4
CDM-760 Advanced High-Speed Trunking Modem MN-CDM760
7–74
When the presence of the optional K4 GZip Compression is detected, this page provides a live
graphical representation of the trending characteristics that are available while using this feature.
Once you open or refresh this page, allow some time for the modem to compile and
graph the performance statistics. If you resize the browser window, allow
approximately 5 to 10 seconds for the graph set to regenerate, then re-center in the
browser window.
This page provides three performance graphs and four configuration status graphs:
Rx Percent Decompression Graph
The Rx Percent Decompression graph represents the WAN to LAN decompression statistic as
described in Sect. 6.2.3.6.3 (Monitor: Stats) Compression

LanToWan or WantoLan . Rx
Percent Decompression (% DeComp) is calculated using the following formula:
100 * (1-(Bytes Out/Bytes In))
Rx WAN Capacity Graph
The Rx WAN Capacity graph logs the following information:
•
Avail means “Available Capacity” or what the satellite link is capable of receiving at any
given moment. Available Capacity is calculated using the following formula:
(Rx Symbol Rate)(Rx Spectral Efficiency)
Spectral Efficiency is a function of ModCod, Pilots On or Off, and Normal or Short Block
being used.
See
Appendix B. Es/No MEASUREMENT
for detailed information about
and reference tables pertaining to Spectral Efficiency.
• Used means “Capacity Used” or the data rate of all traffic sent over the satellite before
decompression (if enabled), and including any overhead the far end modem asserts due
to encapsulation or overhead due to compression. The Capacity Used is taken directly
from the “Bytes from WAN” Monitor Statistics, as averaged over the graphed time
period. When decompression is enabled, the capacity used may be substantially less
than the terrestrial rate of the user traffic due to the effect of the compression card.
Rx ModCod and Local Es/No Graph
The Rx ModCod and Local Es/No graph logs two pieces of data in time synchronous manner:
•
The left side of the graph has a vertical key of Rx ModCod (blue).
•
The right side of the graph has a vertical key of Local Es/No (red).
•
The Local Es/No is the Es/No of the local modem. When more than one ModCod is
received in the smallest interval period allowable by the graph, the most common
ModCod received in that time interval is displayed.
Rx Capacity Configuration Parameters Graphs
The Rx Capacity Configuration Parameters graphs provide a graphical representation for some
of the common configuration settings that can affect user data rate, and typically do not change:
• Pilots On or Off
•
Normal Block or Short Block