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Packet Processor

The Packet Processor enables efficient IP networking and transport over satellite by adding routing capability with very low overhead

encapsulation, header compression, payload compression and Quality of Service to the CDM-625. The advanced QoS combined with

header and payload compression 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.

Header Compression

The Packet Processor incorporates industry-leading header compression for IP traffic. 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. the 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%. And, bandwidth requirements for typical Web/HTTP traffic can be reduced by 10% or more with TCP/IP header

compression.

Payload Compression

The Packet Processor incorporates industry-leading payload compression for IP traffic. Implemented in the hardware for maximum

throughput and efficiency, payload compression can reduce the required satellite bandwidth by as much as 40-50%.

Streamline Encapsulation (SLE)

The Packet Processor incorporates Comtech EF Data’s patent-pending very low overhead Streamline Encapsulation (SLE). SLE can

reduce the encapsulation overhead by as much as 65% compared to industry standard HDLC.

Advanced Quality of Service (QoS)

The Packet Processor incorporates multi-level QoS to ensure the highest quality service with minimal jitter and latency for real-time

traffic, priority treatment of mission critical applications and maximum bandwidth efficiency.

Supported modes are:

• DiffServ – Industry-standard method of providing QoS enabling seamless co-existence in networks that implement DiffServ

• Max/Priority – Provides multi-level traffic prioritization with the ability to limit maximum traffic per priority class

• Min/Max – Provides a Committed Information Rate (CIR) to each user defined class of traffic with the ability to allow a higher

burstable rate depending on availability

Managed Switch Mode

Managed switch modem enables layer 2 operation with the Packet Processor. This provides significant bandwidth savings for layer 2

operation with very low overhead Streamline Encapsulation, header compression and payload compression.

Quad E1 Interface (QDI) with Enhanced D&I++

The CDM-625 supports a Quad E1 interface that can aggregate up to four full or fractional E1s into a single carrier, with very low

overhead. This provides significant CAPEX savings by reducing the number of modems and could possibly reduce the BUC/HPA size

by eliminating the multi-carrier backoff. A proprietary, closed network drop & insert (D&I++) allows for dropping or inserting any

combination of 1 to 31 time slots on each E1. D&I++ is supported for E1-CCS only.

IP Sub Multiplexer

The IP sub mux allows multiplexing IP/Ethernet traffic with serial or G.703 traffic into a single carrier. This is particularly useful for

cellular backhaul when both E1 and IP backhaul is required. This reduces the number of modems and could possibly reduce the

BUC/HPA size by eliminating the multi-carrier backoff. The IP sub mux ratio ranges from 9:1 (IP data rate is 9 times that of the serial or

G.703 data rate) to as low as 1:59.

EDMAC & AUPC

The CDM-625 supports EDMAC, EDMAC-2, EDMAC-3 and AUPC. EDMAC/EDMAC-2/EDMAC-3 can be used to monitor and control

the distant end of a satellite link using a proprietary overhead channel. EDMAC-3 is also used for SNMP management of the distant

end modem. AUPC enables automatic uplink power control for a duplex link.

Management & SNMP Proxy

The modem can be managed via the front panel, the remote M&C port (EIA-232/EIA-485), or the 10/100Base-T Ethernet port. With

support for SNMP, HTTP and Telnet, the modem can be easily integrated into an IP-based management system.

The CDM-625 can also act as SNMP proxy for the distant end modem. This allows distant end modem management using SNMP

without requiring an end-to-end IP link.

IEEE 1588v2 Precision Time Protocol (PTP)

PTP has emerged as the key technology for frequency, time and phase synchronization over a packet network. The CDM-625 is the

first satellite modem to incorporate hardware support for PTP, thereby significantly improving synchronization accuracy for satellite

backhaul. PTP requires Revision 2 modem hardware.

Advanced FSK for LPOD Monitoring & Control

The Advanced FSK allows for monitoring and control of LPOD through modem front panel menus, serial remote control and Telnet.

Feature Enhancements

Enhancing the capability of the CDM-625 in the field is easy. Features that do not require additional hardware can be added on site,

using FAST access codes purchased from Comtech EF Data.

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