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describe the new zstd protocol

pull/116/head
bert hubert 2020-04-28 14:55:48 +02:00
parent c3737713e1
commit 53f91088e0
1 changed files with 15 additions and 0 deletions
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architecture.md
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@ -58,6 +58,21 @@ Both rtcmtool and ubxtool can send data over TCP/IP, but also to standard
output. This standard output mode makes it possible to pipe the output of
these tools straight into navdump or navparse.
There are two transport protocols, one uncompressed, which consists of the 4
byte magic value, a 2 byte length field, and then the message. This protocol
has been deprecated for TCP, but it is still there for --stdout output.
The second protocol is zstd compressed, and features acknowledgements. The
protocol is an initial 4 byte magic value "RNIE", followed by 8 reserved
bytes which are currently ignored. Then zstd compression starts, each
message consists of a 4 byte message number, followed by a two byte length
field, followed by the message. There are no further magic values beyond the
first one.
The receiver is expected to return the 4 byte message number for each
message received. Messages which have not been acknowledged like this will
be retransmitted on reconnect.
Storage details
---------------
Storage is very simplistic but robust. For every receiver, for every hour,