It is possible to use more than one Repeater within a network. To eliminate the risk of
creating a loop, the "Number of repeaters" has to be set in all units in the network, including
the Repeater units themselves.
Warning: Should Repeater mode be enabled "Modulation rate" and "FEC" must be set
to the same value throughout the whole network to prevent frame collisions occurring.
Number of repeaters
Default = 0
If there is a repeater (or more of them) in the network, the total number of repeaters
within the network MUST be set in all units in the network, including the Repeater units
themselves. After transmitting to or receiving from the Radio channel, further transmission
(from this RipEX) is blocked for a period calculated to prevent collision with a frame
transmitted by a Repeater. Furthermore, a copy of every frame transmitted to or received
from the Radio channel is stored (for a period). Whenever a duplicate of a stored frame
is received, it is discarded to avoid possible looping. These measures are not taken when
the parameter "Number of repeaters" is zero, i.e. in a network without repeaters.
Stream
In this mode, the incoming bytes from a COM are immediately broadcast over the Radio
channel. COM port driver does not wait for the end of a frame. When the first byte is coming
from a COM, the transmission in the Radio channel starts with the necessary frame header.
If the next byte arrives before the end of transmission of the previous one, it is glued to it
and the transmission on the Radio channel continues. If there is a gap between incoming
bytes, the byte after the gap is treated as the first byte and the process starts again from the
beginning. Padding is never transmitted between block of bytes.
The receiving RipEX transmits incoming bytes (block of bytes) from the Radio channel to
both COM ports immediately as they come.
When the ETH interface is used simultaneously (e.g. for remote configuration), it works as
the standard bridge described above. ETH frames have higher priority, i.e. the stream from
COM is interrupted by a frame from Ethernet.
Stream mode is recommended to be used for time-critical application only, when the first
byte has to be delivered as soon as possible. However there is not any data integrity control.
If the Baud rate of COM is significantly lower than the Modulation rate on the Radio channel,
frames are transmitted byte by byte. If it is higher, blocks of bytes are transmitted as frames
over the Radio channel.
NOTE: Stream mode can not be used when there is a Repeater in the network
Advanced parameters
Others
Radio ARP timeout [min]
TX Delay [bytes]
Default = 0 [0=0ff, 1600=Max]
Each packet is delayed before it is transmitted on Radio channel for time, which is
equal to the time needed for transmition of the number of bytes set. This time depends
on the set Modulation rate. E.g. if you want to delay all packets for time which equals
the transmission time of a UDP packet with 150 user data bytes, you need to set 178
bytes (20B IP header, 8B UDP leader, 150B user data).
121© RACOM s.r.o. – RipEX Radio modem & Router
Advanced Configuration
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