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Reliable datagram protocols - select repeat ARQ etc.

0 votes
I've set myself the goal to simulate a serial stream over XBee API mode (i.e. use XBee addressing/meshing and support a reliable datagram with crcs and acks).

It's been an interesting exercise. Timing the packets and optimising packet size has been important.

But as for the actual protocol, am wondering if there has been any work done on this? A crude select repeat ARQ is giving me ~224 bits per second at 9600baud with 100byte packet sizes.

Am convinced we can do better. i.e. the protocol might be able to be tweaked to only send a single ack/nack per window rather than per frame.

Am curious to know if anyone has been down this road before me and what their conclusions were.
asked Sep 10, 2015 in RF Solutions and XBee by nzfarmer New to the Community (5 points)
recategorized Sep 11, 2015 by LeonidM

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3 Answers

0 votes
Which XBee product and firmware version are you working with?
answered Sep 11, 2015 by mvut Veteran of the Digi Community (11,300 points)
0 votes
A pair of XBee 900 Pros
answered Sep 11, 2015 by nzfarmer New to the Community (5 points)
If you are referring to the XBee PRO 900 HP or the old XBee PRO 900 product and related firmware versions, then your maximum payload size is 256 bytes per RF packet. In both cases, this was derived from the NP command.
0 votes
Thanks. But what about the selection of algorithms for a secure datagram layer? Has this been implemented before?
answered Sep 14, 2015 by nzfarmer New to the Community (5 points)
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