Comtech EF Data CTOG-250 - Manual (Page 26)

CTOG-250 Comtech Traffic Optimization Gateway Revision 1
Introduction MN-CTOG250
1–4
• Chapter 5. FAST ACTIVATION PROCEDURE
• Sect. 7.4.4.2.3 (CTOG-250 Web Server Interface) Admin | FAST Page
1.2.1 CTOG-250 / CDM-800 Integrated Operation
The CTOG-250 with integrated CDM-800 Gateway Router:
• Is compatible with Comtech EF Data’s CDM-840 Remote Router for Variable Coding and
Modulation (VCM) operation.
• Supports reception and transmission of IP data over satellite links via two fundamentally
different types of interface – IF and data:
o
The IF interface provides uplink connectivity with the satellite.
o
The data interface is a bidirectional path that connects the customer’s equipment
(assumed to be the Data Terminal Equipment, or DTE) to the unit (assumed to be the
Data Communications Equipment, or DCE). All terrestrial data is connected using the
available 10/100/1000 Gigabit Ethernet interface.
1.2.2 DVB-S2 Transmitter
The CTOG-250, via the CDM-800’s modulator, supports enhanced GSE encapsulation and label
filtering insertion for up to 2,047 unique labels. It supports DVB-S2 QPSK, 8-PSK, 16-APSK and 32-
APSK modulation up to 62 Msps with transmit data rates up to 160 Mbps depending on the
modulation type and code rate.
In DVB-S2 operation, the CDM-800’s transmitter operates in the VCM mode. The receive modem
automatically detects for spectral inversion pilots ON/OFF, spectral rolloff of 20%, 25% or 35%,
frame size NORMAL/SHORT, and automatically detects the modulation and code rate (MODCOD).
1.2.3 Outbound Adaptive Coding & Modulation (ACM)
ACM allows each remote in a shared outbound to achieve maximum efficiency and throughput
by operating at the best MODCOD, subject to current conditions. Each remote reports the
current receive conditions to the ACM controller at the Hub, which adjusts the MODCOD for
traffic destined to that remote. The ACM controller selects the MODCOD on a frame by frame
basis to optimize efficiency and availability.
Without ACM the shared outbound would have to be dimensioned for the most disadvantaged
remote leading to significantly inefficient operation. ACM maximizes network efficiency and
throughput under all conditions – be it location disadvantage, rain fade, inclined orbit operation,
interference or other impairments.