Comtech EF Data CDM-750 Installation And Operation Manual page 126

CDM-750 Advanced High-Speed Trunking Modem
Ethernet Management
When the presence of the optional K4 GZip Compression is detected, the 'TxGraph' pages
provide a live graphical representation of the trending characteristics that are available while using
this feature.
Click the appropriate time interval page tab – TxMinutes, TxHours, or TxDays – to view the
pertinent performance graph sets. Figure 6-16 shows, for the purpose of example, the nested
TxHours page.
The time interval afforded each nested page is self-explanatory. When the top-level TxGraph
menu tab is selected, the page view defaults to the TxMinutes page. Click the desired tab to view
any other nested graphing page to continue.
Note: Once any graph page is selected, allow some time for the performance statistics to be
compiled, then graphed. If the browser window is resized, allow approximately 5 to 10 seconds
for the graph set to regenerate, then re-center in the browser window.
On each page, a set of four graphs is provided. The function of each graph on each page is
identical, and is explained thusly:
•
Tx Percent Compression (% Comp) – This graph represents the LAN to WAN
compression statistic as described in Sect. 5.2.2.3.6.3 Monitor: Stats
LanToWan. Tx Percent Compression is calculated using the following formula:
•
Tx WAN Capacity (Avail/Used) – The following information is logged into the Tx
WAN Capacity graph:
o Avail means Available Capacity, or what the satellite link is capable of
o Used means Capacity Used, or the data rate of all traffic sent over the satellite
•
Tx ModCod and Remote Es/No (ModCod / Rem Es/No) – This graph is particularly
useful when the modem is running is ACM mode as it maps the remote Es/No of the far
end modem synchronously along with the near side (local) Tx ModCod used. Note that
two pieces of data are graphed in time synchronous manner:
o The left side of the graph has a vertical key of Tx ModCod (blue).
o The right side of the graph has a vertical key of Remote Es/No (red).
In this format, the graph depicts changes in ModCod that occur when the reported
Remote Es/No meets the Es/No trigger points to switch up or down.
100 * (1-(Bytes Out/Bytes In))
transmitting at any given moment. Available Capacity is calculated using the
following formula:
(Tx Symbol Rate)(Tx Spectral Efficiency)
Spectral Efficiency is a function of ModCod, Pilots On or Off, and Normal or
Short Block being used. Refer to Appendix A. Es/No MEASUREMENT for
detailed information about and reference tables pertaining to Spectral Efficiency.
after compression (if enabled), and including any overhead the modem asserts
due to encapsulation or overhead due to compression. The Capacity Used is
taken directly from the "Bytes to WAN" Monitor Statistics, as averaged over the
appropriately graphed time period (i.e., TxMinutes, TxHours, or TxDays). When
compression 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.
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MN-CDM750
Compression