Header And Payload Compression; Ip Header Compression - Comtech EF Data CDM-570A Installation And Operation Manual

CDM-570L/570AL Satellite Modem with Optional Packet Processor
Appendix D
From the CDM-570A/570AL-IP front panel – Select (UTIL: FAST) FAST Configuration  Demo
Mode  ON. Press ENTER. The Demo Mode Timer decrements from 2592000 seconds (30
calendar days) but can be stopped at any time by setting Demo Mode to OFF.
From CDM-570A HTTP Interface – Use the Admin | FAST page Demo Mode drop-down list to
set operation as Enabled, and then click [Submit]. The Demo Mode timer decrements via the
Demo Time Remaining: XX days XX hours XX minutes banner. To stop Demo Mode at any
time, use the drop-down list to set operation as Disabled.
Make sure to reboot the unit any time you turn Demo Mode ON (Enabled) or OFF
(Disabled).
D.1.2.7.2

Header and Payload Compression

D.1.2.7.2.1 IP 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 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. Using IP/UDP/RTP Header Compression, the same traffic only
needs 10.8 kbps total WAN satellite bandwidth to cross the link. A total maximum of 64
simultaneous VoIP calls can be compressed. Normal HTTP (Web) traffic can be reduced an
additional 10% via IP/TCP header compression.
In addition, bandwidth requirements for typical Web/HTTP traffic can be reduced by 10% or
more with TCP/IP header compression. The Packet Processor supports Header Compression for
the following Ethernet and Layer 3, 4 & 5 Headers:
Supported Ethernet Headers
Ethernet 2.0
Ethernet 2.0 + VLAN-tag
Ethernet 2.0 + MPLS
802.3-raw
802.3-raw + VLAN-tag
802.3 + 802.2
802.3 + 802.2 + VLAN-tag
802.3 + 802.2 + SNAP
802.3 + 802.2 + SNAP + VLAN-tag
802.3 + 802.2 + SNAP + MPLS
Note the following:
•
Header Compression Configuration is completely independent from QoS, and there is no
configuration required except enabling the Header Compression feature on both the
sending and receiving Comtech EF Data IP modem. Packets with a Header Compression
Supported Layer 3 & 4 Headers
IP
TCP
UDP
RTP (Codec Independent)
D–16
MN-CDM570A
Revision 3