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[aprssig] Designating HOME Igates

Robert Bruninga bruninga at usna.edu
Sat Jun 18 00:55:39 UTC 2005


>> I disagree.
>> Every APRS operator has a home area, and 
>>being able to have the system deliver his 
>>traveling packets effeciently back to his "home" 
>>should be a significant part of the job of APRS.  
>
>Why?  The operators in our coverage area would 
>rather not have somebody beaconing on our 
>RF frequency... regardless of whether that person 
>is "from" here. 

If the person is driving locally and then leaves for a trip
he still is one person in your area and I think in
most friendly APRS areas, the locals like to keep
up with each other as they travel.  The load on the
local network doesnt change whether he is local
or driving across the USA.

> And your "plan" does nothing to enforce those 
>packets to be from a formerly "local" station
>(because you can't do it).

My original plan did.  I had proposed that the request
for "HOME" could only be made locally on RF before
the person left.  But that seemed restrictive, but
could still be an option for paranoid areas.

>As I said, if your goal is so your unlicensed spouse 
>can go in and look at your home station to see where 
>you are, read the regulations regarding broadcasting 
>to the general public.

Not at all.  APRS users in our area are a friendly
bunch and like to keep up with each other
(that's why we have radios and APRS).  WHen
one of us is travelling its nice to use APRS to
include them still in the "local" net...

With IRLP and ECHOlink and APRS, then, seeing
where they are, and that they ARE mobile at
the time, makes for easy to arrange (via APRS)
a voice QSO too.  But only if you can see him on
your mobile... (which requires the HOME function
that I want to see in APRS)...

>As I pointed out, your "plan" cannot work in the 
>current APRS-IS network nor should it.  APRS 
>was never designed for the operator to "deliver"
>his packets to an arbitrary area

It most certainly was designed to have that
capability (not for routine operations, but for
the occassional need)....  And it works well for
those who are willing to take the time to
understand what a digi path is...

> (note that the "destination" field in the AX.25 
>packet is not used to indicate a destination).  

No but the path does.  I agree that these days
with overloaded networks, such activity beyond
a few hops is of little value, but that still does not
eliminate the "need" for a station to be able to
direct his packets "home"...  Hence do it via IGates
which give the capability unlimited range...

>After designing APRS, you tried to add all types 
>of source routing (SSID, UI-Flood, UI-Trace, etc.)

Not true.  Source routing was always inherent in
AX.25, and APRS only overlayed on top of that.
APRS primarily focused on one-to-all local distribution,
but no where did it make any attempt to eliminate
the ability for source routing over a given, chosen
path.  In fact, such paths were encouraged for
anything beyond 2 hops.

Though again, these days, with the load it is of
no practical value on RF.  That is why the APRS-IS
should do it for us if needed by a traveler far from
home.

> The AX.25 UI protocol is a "multicast" protocol
>best suited to local RF operations.  Yet, you consistently 
>try putting a "but" into these facts by saying 
>"I want my packets to be heard over there, too."  

You missunderstand the issue.  I have no desire to
send my packets willy-nilly all over the place.  I want
to be able to send them HOME to my LOCAL
OPERATING area where I am a participating member
of a LOCAL RF net.  That is why the APRS-IS which
is NOT RF should get my traveling packts back here
if I want so that it remains a LOCAL RF issue.

>This is where most of the congestion problems 
>originate today: people trying to get their packets 
>"over there".

True, and I agree, but that has NOTHING to do with
getting them back HOME.  There is a big difference 
between getting them "over there" and getting
them  HOME to my local area (without bothering
everyone inbetween)...  

This concept of HOME makes absolutely no impact
on the local RF network.   If I am home, my packets
are on RF at home.  If I am on a rare trip, my
packets could still get HOME if I select the home
option.  There is no added burden on the local RF
net at all.  In fact, it could be said to be less, since
via the IGate, my packets should only go one h op
not 2...

>As I said, if you want to communicate with a specific 
>station, send a message to them.  

My experience is that the IGates do not check for
the succcess of their local-courtesy-position packet
and onlyh send it once every 30 minutes if the
QSO continues.  If the first position packet collides
then you wont see them.  And that is why this technique
does not work.  If the IGate, made sure to LISTEN
to verify that the courtesy position packet got out,
then this technique would be much more useful.

I have had very little success with it.  Especially in
poorly set up IGates..

>If you want to send bulletins, weather, posits, or
>whatever to our area just because you can, thank 
>goodness the IGate authors had the foresight to 
>keep you from doing that.

Absolutely agree there.  But that is not what we
are tallking about.  We are talking about adding
the concept of "HOME" destination for a travelers
packets far from home.  And I'd be happy if the
IGate would filter it down to no more than once per
5 minutes just to be safe too...


>APRS is a broadcast protocol, not a point-to-point 
>protocol.  Don't try to make it a point-to-point protocol 
>because you will fail just as miserably as your 
>attempt to make AX.25 a routing protocol.

Not trying to do either.  Just trying to get the
IGates to recognize the concept of a HOME 
IGate for travelers away from home.  ANd finding
a way to do it so that it is not a management
burden on the IGate operators.  That is all.

de Wb4APR, Bob





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