Ecm Overview - Comtec CDM-840 Installation And Operation Manual

CDM-840 Remote Router
Appendix G
Abbreviation Term
SUM Status Update Message
Transmission Announcement
TAP
Protocol
VMS Vipersat Management System
G.1.2

ECM Overview

•
Comtech EF Data CDD-880 Multi Receiver Router Installation and Operation Manual
(CEFD P/N MN-CDD880)
•
Comtech EF Data ODM-840 Remote Router / ODMR-840 Reduced Form Factor
Remote Router / ODMR-840B Remote Router Board Set Installation and Operation
Manual (CEFD P/N MN-ODM840)
Figure G-1 illustrates the processing diagram for ECM (Entry Channel Mode) messaging. ECM is a
feature based on slotted Aloha with random retransmission backoff. ECM supports multiple
carriers through frequency assignments, which provide simplified deployment and scalability.
Figure G-1. ECM – Message Processing Diagram
G–2
Comments
SUM is used for updating VMS device control
parameters, such as Tx Frequency, Data Rate, Current
MODCOD, Eb/No, Es/No, ACM information, etc.
The TAP is the time and frequency reference
message sent on intervals to synchronize any
listening CDM-840s into the Entry Channel.
A VMS is a configuration, management, and control
tool that is used to configure the Advanced VSAT
Network and respond to network anomalies.
MN-CDM840
Revision 3