[aprssig] IS-to-RF packet Weighting

Andre aprs at pe1rdw.demon.nl
Wed Dec 28 18:11:19 EST 2011

True 30 seconds delays are to be expected but there is still the 
checking for call in the digipath, the only way to defeat that loop 
block is if someone runs a digipeater that strips out the used path, 
when someone goes to that level of stupidety then there is nothing to 
prevent a loop from forming and even then the loop would not go trough 
the aprs-is but stay on rf and most likely die out there in one or 2 
loops if it even makes it trough one loop, loops like that can and might 
already be happening right now.

xband digipeaters have been in use as long as the first hf gates came on 
aprs, the only difference is that now the hf channel is replaced with an 
axudp link and the gate limiting is the otherway around, for hf gates 
only a path with hfgate gets put trough to hf, in this case only a path 
with the specific udp gate call gets gated trough. in essence only one 
gate will ever gate the packet over to 2 meter, where with igates it can 
and does happen that a message is gated by 2 or 3 igates because they 
don't know what gate is going to send it along, all they know is if the 
adress station of the message is local enough.

About the specs but I remember thet 3th party format was invented for 
bob's ziplan concept long before the specs where put in place.
You could say aprsdos with ziplan was the orginal igate and loops back 
then where no concern.

73 Andre PE1RDW
Op 28-12-2011 23:39, Pete Loveall AE5PL Lists schreef:
> We found out early on that dupe checking alone is not sufficient.  It is very easy to introduce>30 second delays on RF as well as some Internet configurations.  IGates do not block loops.  Servers block loops that fall within their dupe windows.
> The reason for the third-party packet requirement for gating to RF is to help servers and IGates block those packets from repropagating.  Also, the third-party packet tells an IGate what other IGates are on the frequency (no need to gate to RF a message destined for another IGate).  There is a reason for the specifications.  Deviations from those specs can be expected to cause issues.
> This is not digipeating, it is gating which is significantly different.
> 73,
> Pete Loveall AE5PL
> pete at ae5pl dot net
>> -----Original Message-----
>> From: Andre
>> Sent: Wednesday, December 28, 2011 4:29 PM
>> Don't excisting igates already block loops between eachother?
>> In my proposal because it is digipeater based, loops are already filtered out
>> by dupechecking, digined does not process any packet it has in it's dupe
>> buffer, has the digicall in the path as been digied or has the digicall as sender.
>> excisting specs already work for paralel vhf and uhf networks.
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