136 | Managing the Radio
Aprisa SRi User Manual 1.1.0
Initial Setup for Mirrored Bits® Support
The MTU can be adjusted up or down in steps of 8 bytes
•
Increase by 8 bytes if Mirrored Bits® is not running without alarms or ROK assertions
•
Decrease by 8 bytes if Mirrored Bits® is running error free, the target is to find the smallest MTU for
reliable transport
If reliable Mirrored Bits® communications cannot be achieved after increasing the MTU by 10 steps or 80
bytes, then the following CLI commands can be used to extract low level packet information from the radio.
This information can be forwarded to 4RF to determine what is occurring and identify alternate
configurations.
•
Configure Radio / Mirrored Bits® equipment for 9600 baud rate.
•
Connect Mirrored Bits® equipment to one of the serial ports and start traffic.
•
Ensure no management traffic or other services are connected to the Ethernet or Serial ports.
•
Login to the radio CLI as
‘
admin
’
and execute
‘
debug set 2 5
’
-> there will be continuous scrolling
information.
•
Screen capture one page of the scrolling information to send to 4RF.
•
Remove serial cable and execute
‘
debug clear 2 5
’ via the CLI
to clear the debug routine,
alternatively reboot the radio.
•
Note if the serial baud rate intended to be used is not 9600 then repeat for each different rate and
clearly identify the screen prints by baud rate before forwarding to 4RF.
Note there are additional low level configurations which can improve performance. 4RF will detail these if
required based on the information received.
Additional Setup for Improved Latency or Additional Services
Once reliable Mirrored Bits® communications has been achieved, experimentation can be undertaken to
reduce latencies or provide support for additional services such as Ethernet based SCADA polling.
Increasing the MTU will impact latency for each packet (refer to table in section 4). A point may be reached
where the gaps between individual packets are too high and the Mirrored Bits® ROK or other alarms will
assert.
Increasing the MTU allows some ‘space’ in each packet for additional data from the second serial port o
r
the Ethernet ports.
Support for Ethernet is highly dependent on the size and frequency of packets being sent. A level of trial
and error is required. At the slower OTA data rates, support may be limited however with higher OTA data
rates some services may be supported (such as polling).
It should be noted that if the Mirrored Bits® devices or network manager can accept occasional ROK
assertions then there is more flexibility for other services.
