Managed Switch Multicast Option; Header/Payload Compression Refresh Rate - Comtech EF Data CDM-570 Installation And Operation Manual

CDM-570/570L Satellite Modem with Optional IP Module
Ethernet IP Module - CLI and Telnet Operation
14.2.2.8

Managed Switch Multicast Option

The Managed Switch Multicast Option (Modem Firmware Ver. 1.5.4 or later; this feature was
titled easyConnect Multicast Option in Modem Firmware Ver. 1.5.3.6 or earlier) page from the
Administration page. It allows multicast to be either transmitted or received through the modem.
This applies to Managed Switch Mode only. Managed Switch Mode will normally filter
multicast traffic.
If the Working Mode is Managed Switch and multicast traffic is intended to
pass across a pair of modems, this option must be enabled on both modems.
14.2.2.9

Header/Payload Compression Refresh Rate

The Header Compression Refresh Rates are configured from the Administration page.
Selection
Header comp refresh rate
(in pkts) for UDP/RTP1
Header comp refresh rate
(in pkts) for UDP
Header comp refresh rate
(in pkts) for all others
The Header Compression Refresh Rates determines how many compressed header packets are
sent before a single full header packet is sent. Some compressed header traffic could be lost
during deteriorated satellite link conditions. Sending a full header packet will allow the return of
the traffic stream. Refresh rates from 1 to 600 can be individually selected for UDP/RTP1, UDP
and all other IP headers. The Refresh Rate can be decreased for poor satellite link conditions or
increased to further reduce overhead. The default Refresh Rate of 50 has been found to provide
the best performance and efficiency in typical satellite link
Managed Switch Mode will automatically use L2 Header Compression (even if
Header Compression option has not been purchased). Because of this, some of
the initial traffic sent between two devices will not be received over the satellite
until a full Header is transmitted. For example, the default Header Compression
Refresh Rate is 50 packets. If a ping is sent over the satellite, it will time out
until the full Header packet is sent. The Header Compression Refresh Rate on
the Administration Menu can be reduced to minimize the amount of traffic lost
when traffic is first sent between two devices. Once communication between
two devices has been established, both modems are able to receive all traffic,
unless one modem is power cycled or reset.
Entry Description
H Selects how often a single, full header UDP/RTP1 packet is transmitted with
Header Compression enabled.
U Selects how often a single, full header UDP packet is transmitted with
Header Compression enabled.
O Selects how often a single, full header packet is transmitted with Header
Compression enabled (for all other types of IP headers).
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MN/CDM570L.IOM