Re: xAP EOM identifier in xAP v1.3

[Kevin Hawkins <yahoogroupskh@xxxxxxxxxxxxxx>]

This is a graphical front end  iPhone application (iViewer byCommand
Fusion) .  They have TCP/UDP socket support to handle two way
interaction with remote devices for status updates and control.   They
are not writing anything specifically for xAP - just hoping to be able
to support it, and their parsing works best if they can handle complete
messages by way of an EOM identifier or UDP receive event.

In practice they have experienced occasional truncated or concatenated
messages and so were suggesting an EOM would be most helpful.  The
truncation may well be due to a partial concatenation which would
otherwise exceed the a buffer boundary and not any data lost.  They want
something compatible  with as much xAPware as possible and as they're
not coding specifically for xAP and are using UDP.  The double '0A'
seems most suitable for them and anyone else with a similar need.

The UDP datagram size seems to be quite a debateable issue.  RFC 879
apparently says "The default IP Maximum Datagram /size/ is 576"
but  it
seems this is now rather archaic in terms of implementations and rarely
a LAN concern.  I did find that AMX truncates at 512  bytes though,
whilst trying to get my xAP AMX module running - in the end I had to use
TCP to xServer..  I think this was more a convenient software buffer
size than any other reason and I hope they have increased this in later
firmware

K



Patrick Lidstone wrote:
>
> Perhaps you can share more of the specific details of the device(s) in
> question (manufacturer, docs, o/s etc), and their specific behaviour,
> which seems a bit anomalous?
>



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