Comtech EF Data CDM-625 - Manual (Page 416)

CDM-625 Advanced Satellite Modem Revision 15
IP Packet Processor Option MN-CDM625
18–4
18.2.5.1 Header Compression
The IP 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 Voice-over-IP (VoIP), header compression can provide bandwidth
savings exceeding 60%. For example, 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%.
In addition, bandwidth requirements for typical Web/HTTP traffic can be reduced by 10% or
more with TCP/IP header compression.
18.2.5.2 Payload Compression
The IP Packet Processor features 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%.
18.2.5.3 Advanced Quality of Service (QoS)
The IP Packet Processor incorporates multi-level QoS to ensure the highest quality of service
with minimal jitter and latency for real-time traffic, priority treatment of mission critical
applications and maximum bandwidth efficiency.
The supported modes of QoS 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
When using rule-based QoS, you can configure up to 32 different rules based on:
• Source IP address and subnet mask • Destination IP address and subnet mask
• Source Port • Destination Port
• Protocols (well known) • Priority