StreamCaster MIMO Radio User Manual
4/30/19
10017C000
Silvus Technologies Confidential
Page
87
Quality of Service Port Classification:
The Quality of Service configuration page allows the user to make a distinction between low and
high priority traffic transmitted through each radio. High priority traffic will always jump to the
front of the queue and bypass any awaiting low priority traffic. In instances where the link cannot
support the amount of data trying to be transmitted, low priority traffic may be completely
shelved in order to ensure that the high priority traffic gets through.
To specify Low/High priority traffic, the user needs to simply input the port number that the
traffic will be arriving on. Multiple ports of the same priority can be separated by a comma (i.e.
5001, 6001, 6002). Alternatively, the user can specify a range of ports using a dash (i.e. 5001-
5006). Any combination of commas and dashes will work as well (i.e. 5001, 6001-6007, 8000).
Any field can be cleared by removing the text and clicking ‘Apply’ or ‘Save and Apply’. If
unspecified, traffic is treated as Low Priority.
Quality of Service Contention Window Control:
The Quality of Service Contention Window Control tunes the aggressiveness of CSMA backoffs
when collisions occur. The MAC takes random backoffs in the range [0, 2^cw_min]. Every time
there is a collision/noise it will increase this cw_min by 1, until it is capped by cw_max.
E.g. 4,10 translates to random backoffs in the range [0,16] in the beginning for a packet. If the
first try results in a collision, it will pick another backoff in the range [0,32], then [0,64], until
[0,1024]. After successful transmission, backoff is reset to [0,16]. The default is 4,10 for low
priority, and 3,6 for high priority. For larger networks, it is recommended to increase the Low
Priority minimum to reduce the chance of collisions occurring.
End-to-End Automatic Repeat request (Beta Feature
–
License Enabled)
The End-to-End ARQ feature provides packet re-ordering capability to the radio. This feature is
useful in applications that are sensitive to out of order packets (i.e. video applications where the
decoder does not have the ability to re-order packets).
To enable packet reordering, specify the port number of the subject data in the same format as
the QoS ports on the source and destination radio. The settings should match on both radios and
do not need to be set on any relays.
Retransmissions Disabled
–
Only packet re-ordering with no end-to-end retransmissions if
packets are lost. The receiver timeout is the length of time the receiver waits for out-of-order
packets before giving up and delivering the data it has in its buffer. This is similar in concept to
