RACOM RipEX 1.12.0, User Manual, Page: 92 / 189

○ Progressivity
List box: Off, On.
Default = Off
When On, the Prog value used in the formula above is calculated as follows:
Prog = Ft * (Nr - 1)
Ft – see above
Nr – the retransmission sequence number, e.g. Nr = 3 when the very same frame is to be re-
transmitted for the third time (Nr = 0 for the initial frame transmission)
○ Fix timeout [bytes]
Default = 350 [10=Min, 10000=Max]
This part of the retransmission timeout is always included (see the formula above). The actual
time equals the time needed for transmittion of the number of bytes set. This time depends on
the set Modulation rate. E.g. when the Fix timeout should equal the transmission of a UDP
packet with 150 user data bytes, you need to set 178 bytes (20B IP header, 8B UDP leader,
150B user data).
○ Variable timeout [bytes]
Default = 350 [10=Min, 10000=Max]
This part of the retransmission timeout is multiplied by an integer random number (see the formula
above) and then included. The actual time is obtained in the same way as for the „Fix timeout
[bytes]“ above.
○ Max Variable [No]
Default = 4 [0=Min, 15=Max]
This number defines the range from which the random integer number is chosen to multiply the
Variable timeout (see the formula above).
○ Busy channel access
An advanced user can modify the RF channel access parameters in this menu. The explanations
below assume general knowledge of collision-oriented MAC layers of layer 2 protocols.
• Busy channel access
An advanced user can modify the RF channel access parameters in this menu. The explanations
below assume general knowledge of collision-oriented MAC layers of layer 2 protocols.
○
TX Delay [bytes]
Default = 0 [0=Off, 16000=Max]
The number of bytes set in this parameter define time period the same way as e.g. the „Fix
timeout [bytes]“ above. This time period is added to the normal access time (i.e. random number
of slots, see below) whenever the RF channel is evaluated as busy in the moment the transmis-
sion is requested. Access to a free channel is not delayed.
○ Slot length [bytes]
Default = 0 [0=Min, 250=Max]
Length of MAC layer access slot. The respective time period is calculated the same way as for
the „Fix timeout [bytes]“ defined above. When value of 0 (default) is set, the slot time is set to
the shortest possible frame size.</p> <p>Beware! Sloth length significantly influences the network
throughput under heavy load conditions. It MUST be set to the same value in every network
member.
○ Slots after RX [No]
Default = 4 [0=Min, 12=Max]
The range from which the random integer number is chosen to multiply the slot length in order
to get the access time period. This value is used when the previous channel event was a data
frame reception (by the same radio). Note that ACK is not considered a data frame.
○ Slots after TX [No]
Default = 6 [0=Min, 12=Max]
RipEX Radio modem & Router – © RACOM s.r.o. 92
Advanced Configuration