Mv – value
"Max Variable [No]"
[0..Mv] represents a random number from sequence 0 to Mv (limiting values included).
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 retransmitted 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 transmition 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 ex-
planations 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 transmission 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.
WARNING: 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]
RipEX Radio modem & Router – © RACOM s.r.o.
124
Advanced Configuration
Summary of Contents for RipEX
Page 2: ......
