USER’S MANUAL__________________________________________________________________
106 _________________________________________________________________ M211322EN-D
The M menu always works from the current parameter values, not from the
saved values in non-volatile RAM. If the host computer has modified some
of the current values, you see these changes as you skip through the setup
list. However, typing S at that point would save all of the current settings
and would, perhaps, make many changes to the original non-volatile
settings. In general, to make an incremental change to the saved settings,
first type R to restore all of the saved values, then type M to make the
changes starting from that point, and then type S to save the new values.
A listing of the parameters that can be viewed and modified with the M
menu is detailed in the following subsections. In each case, the line of text
is shown exactly as it appears on the TTY with the factory default settings.
A definition of each parameter is given and, if applicable, the lower and
upper numeric bounds are shown.
4.2.1 Mc — Top Level Configuration
This set of commands configure general properties of the IFDR.
IP address of networked RVP9/IFD: 10.0.1.254
This is the ethernet address of the remote IFDR module. For best results,
the IFDR should be attached to a dedicated ethernet port of the host
computer and with no routers, switches or hubs in between.
Maximum ethernet incoming UDP frame length : 8192
The (I,Q) time series data from the IFDR are transmitted to the host
computer through ethernet UDP packets. Depending on the receiver
configuration (dual-pol, bin spacing, etc.) the time series data rate may be
as high as 50 MBytes/second. To improve the efficiency of packet
transmission and reception it is very helpful to employ “jumbo” packets,
that is, packets that are longer than the typical 1500-byte standard. The
RVP900 allows jumbo packets up to 8192 bytes to be used.
Limits: 250 to 8192 bytes. Use, for example, “ifconfig mtu 8192 eth0” to
set the receiver Maximum Transfer Unit size on the host computer. Also
make sure that any inline ethernet switches are also configured to transmit
the jumbo packets.
Receive buffer size for incoming UDP packets : 1500000
The UDP time series packets are send-and-forget, meaning that the IFDR
assumes that every transmitted packet is correctly received by the RVP900
host computer. This assumption is reliable as long as there is sufficient
buffering of the incoming data to prevent overruns within the Linux
environment. In most cases the 1.5 MByte default provides reliable
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