Appendix B. Ethernet Statistics And Status Reporting; Introduction; Data Flow Diagram - Comtech EF Data CDM-750 Installation And Operation Manual

B.1

Introduction

Information is available from the CDM-750 Advanced High-Speed Trunking Modem to report
ongoing and time-varying quantities, along with some operational status items. Of particular
interest in this section are those related to the Ethernet data traffic associated with normal
operation and metrics – i.e., items that are attributed new meaning in special modes like Adaptive
Coding and Modulation (ACM) or DoubleTalk Carrier-in-Carrier (CnC). All of the metrics
(counts, configuration, ratios, etc.) are referred to collectively as statistics. (For the purpose of
this application, the intent of using the word 'statistics' here is to gather naturally associated
items.)
Note: This appendix excludes much of the information provided earlier in this manual (e.g.,
Es/No, RSL, etc.) in order to focus strictly on data traffic-related items.
B.2

Data Flow Diagram

A way to visualize the CDM-750 and its data traffic handling capabilities is via the simplified
diagram shown on the next page (Figure B-1). While this figure includes a few of the normal
modulator and demodulator features, its primary purpose is to emphasize the blocks involved in
data flow.
Note the following:
•
The names of the blocks/regions correspond to generic functions within the modem.
•
The blocks in this diagram are numbered to indicate valid traffic flow between blocks.
•
Data flow only occurs as indicated by the lines in the diagram. For example, data flow from
Blocks 1 to 2 is valid, while data flow between Blocks 2 and 8 is not.
•
The arrows in the diagram indicate the direction of data flow; while data flow between
Blocks 1 and 2 is valid, data flow between Blocks 2 and 1 does not occur. Arrows on both
ends of a link show where data flow is bidirectional.
Appendix B. ETHERNET
STATISTICS
B–1
STATUS
AND
REPORTING