Management Interface:10/100Base-T Ethernet for web and SNMP
Compatible with CDM-625 Advanced Satellite Modem equipped with Packet Processor
Comtech EF Data’s Advanced VSAT Series products offer industry-leading solutions for cellular backhaul,
Universal Service Obligation (USO) networks, corporate networks, Internet Service Providers and other
applications requiring high-performance IP transport in a hub-spoke network environment. Incorporating
advanced technologies developed by Comtech EF Data, Comtech AHA and Memotec, these products are
specifically designed to provide unmatched performance at an attractive price for a wide range of
applications in a hub-spoke environment.
The Advanced VSAT Series includes the CDM-800 Gateway Router, the CDM-840 Remote Router, the
ODM-840 Remote Router (outdoor version of CDM-840), the CDD-880 Multi-Receiver Router and the CXU-
810 RAN Optimizer. The products incorporate industry-leading WAN bandwidth optimization to provide the
Physical layer transport without compromising latency
Link layer transport
Higher layer transport
Radio Access Network (RAN) backhaul
Designed for use at the hub site, the CDD-880 can receive transmissions from up to 12 CDM-840 Remote
Routers. It combines a number of advanced technologies in a 1RU platform enabling the most efficient
return channel for hub-spoke networks:
VersaFEC® low-latency LDPC
Ultra low overhead Streamline Encapsulation (SLE)
Lossless Payload decompression
Offshore & Maritime
Mobile Backhaul with
Internet access (ISP)
Maritime & offshore
For efficient IP networking and transport over satellite, the CDD-880 features integrated routing capability with very low overhead
encapsulation, header decompression, and payload decompression. It ensures the highest quality of service with minimal jitter and
latency for real-time traffic, priority treatment of mission critical applications and maximum bandwidth efficiency.
Ultra Low Overhead Encapsulation
The CDD-880 supports Comtech EF Data’s patent-pending ultra low overhead Streamline Encapsulation (SLE). SLE can reduce the
encapsulation overhead by as much as:
65% compared to HDLC
90% compared to AAL5 used in DVB-RCS
90% compared to proprietary framing used by other VSAT solutions
The CDD-880 supports header decompression for IP traffic that is compatible with CDM-840’s (and CDM-625’s) industry-leading header
compression. Header compression can reduce the 40 byte IP/UDP/RTP header to as little as 1 byte. For TCP/IP, the 40 byte header is
reduced to as little as 3 bytes. For applications such as VoIP, header compression can provide bandwidth savings exceeding 60%.
E.g. 8 kbps G.729 voice codec requires 24 kbps of IP bandwidth once encapsulated into an IP/UDP/RTP datagram. With header
compression, the same voice call needs about 8.5 kbps – a saving of almost 65%. Bandwidth requirements for typical Web/HTTP traffic
can also be reduced by 10% or more with TCP/IP header compression.
Lossless Payload Decompression
The CDD-880 supports industry-leading 2nd generation lossless payload decompression for IP traffic that is compatible with CDM-840’s
(and CDM-625’s) industry-leading payload compression. Implemented in the hardware for maximum throughput and efficiency, payload
compression can reduce the required satellite bandwidth by as much as 40-60%.
Advanced Quality of Service (QoS)
The CDD-880 transparently passes the QoS prioritization established at the transmit end by CDM-840 (or CDM-625).
CDD-880 supports VersaFEC Low-latency LDPC. VersaFEC is a patented (Covered by U.S. patents 7,353,444 and 7,415,659. Other
patents pending) system of high performance short-block low-latency LDPC codes designed to support latency-sensitive applications,
such as cellular backhaul over satellite. VersaFEC provides excellent coding gain with lowest possible latency. VersaFEC’s coding
performance is similar to that of DVB-S2 (short block) or LDPC (16k block) with up to 95% lower latency.
Adaptive Coding and Modulation (ACM) Capable
Satellite users have traditionally relied on worst case link margin to overcome rain fade and other impairments which leads to significant
inefficiencies. ACM converts the available link margin into increased throughput – gain of 100% or more is possible. ACM maximizes
throughput under all conditions – rain fade, inclined orbit satellite operation, antenna mispointing, noise, interference and other
The modem can be managed via the web-based user interface or SNMP.
Lesser of +10 dBm or 105 - 10 log(symbol rate,
desired carrier) dBc, uniformly spread across
950-2150 MHz less desired carrier occupied
This spec allows the entire 950-2150 MHz
L-Band to be filled with an average uniform
spectral density that is 14 dB greater than the
desired carrier spectral density
Absolute Maximum, No
20%, 25%, 35%
Receive Symbol Rate (Rs) < 64 ksymbols/sec
± Rs/2 kHz (fixed), Rs in ksymbols/sec