Comtech EF Data CDM-750, Installation And Operation Manual

Page: 173 / 300

CDM-750 Advanced High-Speed Trunking Modem Revision 2
Ethernet-based Remote Product Management MN-CDM750
6–31
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 ‐ 18 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.
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. Note the following:
•
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
Æ
Compression
Æ
LanToWan . Tx Percent Compression is calculated using the following formula:
100 * (1-(Bytes Out/Bytes In))
•
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
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 E. Es/No MEASUREMENT for
detailed information about and reference tables pertaining to Spectral
Efficiency.
o
Used means Capacity Used , or the data rate of all traffic sent over the satellite
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.