[OZAPRS] some comments re the ongoing findu discussion

[Hamish Moffatt]

On Thu, Mar 18, 2004 at 01:54:36PM +1030, John Williams wrote:
> The comments about preserving the digipeat bit or flag on systems that
have already digpeated 
> a packet seems the be handled differently by aprs digipeater
implementations or is it the 
> application used to monitor these frames.

Yes I suspect you are right. I think it is different TNCs outputting the
results in different ways. I think it would be better if everybody used
KISS mode on their TNCs..

> I don't have the ax25 spec to hand, but the address field does have one
bit reserved to indicate 
> if a station has digipeated a packet and I can see no reason once this
bit has been set why it 
> would be reset by the next station to receive this packet.  In fact
evidence would suggest that 
> the digipeated bit state is maintained or can be maintained and it is
perhaps up to the 
> application to check to complete address field and test every address in
the repeater sub field.

The spec clearly says (I checked it this morning) that a repeater should
set the bit, recalculate the CRC, and pass the packet on. Nothing about
clearing the bit on previous digipeater addresses.

> My understanding was that if a station from outside your filtered feed
sent you a message that 
> their position would be sent and away you went.    Did the servers run
something other than 
> javAPRSsrvr originally.   I think aprsd worked in this fashion.

Yes it does.


Hamish
-- 
Hamish Moffatt VK3SB <hamish at debian.org> <hamish at cloud.net.au>
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