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[aprssig] NOSaprs update - cross port digi with callsign substitution

Robert Bruninga bruninga at usna.edu
Wed Jun 22 16:28:58 UTC 2005


Maiko, 
thanks.  I agree with everyone of your objectives.
In fact I started suggesting a level 4 system
for distributing APRS ui packets as early as 1994,
I am thrilled to see this progress...

But I was just pointing out the pitfalls of some
things in your example that cause problems.  If I 
can further elaborate:

>>> <maiko at pcs.mb.ca> 06/22/05 11:02 AM >>>
>> Until some other routing method is developed the senders
>> intent in his  path  should be honored as long as it is not
>> abusive to the network.
>
>My understanding is that with the current routing method, 
>the senders path is of no value.

To some maybe, but to the sender, one has no proof of that.
His path is still what the sender chose to transmit and I dont
think anyone wants their personal transmissions to be
modified along the way in such a way that it appears as
though they originated it.  That just violates every principle
of ham radio.  
NOTE: I am not arguing against path modification in any way, 
its  only that the only paths that should be modified are paths 
that the sender KNOWS before hand *are potential for
modification*

> It is not able to be used in any way by the recipient 
>in the return message, so in the end it just takes up 
>packet space. Is this correct ?

No, the biggest problem in APRS when WIDEn-N came
into common use was its lack of traceablity and 
reversability.  Now all that is fixed with the New-N
Paradigm which now makes ALL paths traceable
at each hop along the way.

>> I would be very incensed to see my packets sent
>> as WIDE2-2, arriving somehwere else as WIDE3-3
>> beacuse someone thougth that their area wanted
>> to make my packets go farther.
>
>Is that really a big deal ?

Absolutely.  WIth all the path police out there now,
I would not want everyone seeing a path in my
packets that I was not responsbile for.   Conversly
if someone does come up with a routing method
that does modify the paths along the way, then
it should only work on paths that I, the sender,
submit to that system.  Currently the historical
use of WIDEn-N is not such a path.

>That's like me calling CQ on 3650, but I don't want
>anyone further than Staten Island to come back to me.

No, its like you calling CQ on 3650 and having
someone in  California, Colorado and Alabama
patching it over to their local VHF repeater.
Your name and call would be mud. when you
did not respond and just jammed their repeaters.

>The point is that I can't control the conditions of the
>network, being a mere sender of a message. 

If you chose a path of WIDEn-N (or befor the new-N
Paradigm) of WIDE or RELAY, there were certain
well published expectations of that path.  YOu expect
the system to follow those expectations.  If you come
up with a system for altering peoples paths, then 
simply choose a different generic indication for it.
This way, the SENDER uses your generic indication
that he does want to use this new system and is 
offering his packet u p for whatever your system
wants to do with it.  But it is the sender's choice.

Again, I am not at all discouting your objectives,
only pointing out that the existing generic APRS
paths of WIDE, RELAY, and WIDEn-N should not
be mnodified along the way beyond their published
expectations or the integrity of the system is being
compormised.


>if you can remember the old days...of BBS forwarding 
>[when] all it took was one sysop to impose his own 
>standards or *restrictions* on what was allowed to 
>forward or not. Things broke very quickly from there. 

Which is exaclty the root of my concerns of the
specific exampl you used that showed a local sysop
modifying someone's packet without his knowledge,
and then sending it on.

You can do that without any objections from me at
all as long as you consider these conepts:

1) The original packet remains intact including
the path (unless it is specifically using a path
that is widely known to be available for modification).

2) The packet be forwarded onward in some kind of
3rd party manner so that there is no question of
what part was the sender's and what part have
been modified by others along the way.

Your example could have been this:
Sender on HF  SENDER>APRS,VHFDX:packet
Here the "VHFDX" I just made up as a generic
PATH indicator indicating that the sender wants
his packet to go as far and wide as it can on 
VHF everywhere and so he is showing that he
is welcoming further modification and distribution
of his path...

Then I would have no objection if some sysop
chose to path that to VHF as the path
SENDER>APRS,VHFDX,URGATE,WIDE3-3

Because then the sender has made the choice 
to let your Gate blather his packet everywhere.
Now then it becomse a local issue of your
GATE flooding the local network with unwanted
VHF DX packets, but that is a separate issue.
The sender and your intent are clearly visible
and so others can decide...

So again, not at all picking at your objectives and
intents.  Just wanted to clarify the paticular
pitfalls of your specific example.

thanks
Bob





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