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[aprssig] Packet routing, path specification.

AE5PL Lists HamLists at ametx.com
Wed Jun 22 18:49:10 UTC 2005

I recommend you read the papers in the Winter and Spring PSR's
(www.tapr.org) on no-source-routing in APRS.  There is a drive on to
implement the stated algorithm in all current smart digipeaters (mostly
software) and new digipeaters (hardware and software).  The NSR
algorithm eliminates user-defined paths and eliminates the failed
attempts to make AX.25 (a link-level protocol) into a routed protocol.
The NSR algorithm promotes the use of APRS as a broadcast protocol (that
is what it is, after all), not a directed protocol (which APRS is not).
It makes APRS on RF a true network, not a mish-mash of individuals
blindly trying to achieve independent objectives on a shared frequency
with abysmal results.

Best of all, it can be implemented today, in today's RF network, with
the only pain felt by those who insist on trying to use the RF network
to see how far they can go on RF.  Be aware, however, that there are
short-sighted, stick-in-the-mud individuals out there who simply can't
grasp the NSR concept nor the concept that repeater owners, not repeater
users, define the repeater network and the same should be said of
today's digipeater owners.

AX.25 has been abused since it was introduced in the late 70's by people
who mistakenly thought that having the ability to define digipeaters in
the packet meant that it is a routing protocol.  The latest version of
the AX.25 specification reduces the allowed number of digipeaters to
two.  There is a reason for this.  The authors of the specification have
seen this abuse, seen what it does to the usability of the protocol
(destroys it), and they want to help people understand that AX.25 is a
link-level (radio station to radio station) protocol.  In the case of
the UI subset of the AX.25 (APRS uses this subset), it can be (and has
been) shown very easily that user-defined paths have caused most of our
congestion problems today in APRS with no benefit to the local amateur
communities overall.

It is time we put to bed those tired old ideas founded in failed
arguments which have been disproved over and over again, and start
looking (as you have) towards a future where APRS is easy to use,
stable, and effective.

I'm done with my soapbox.  Next... ;-)


Pete Loveall AE5PL
mailto:pete at ae5pl.net 

> -----Original Message-----
> From: Rick Green
> Posted At: Wednesday, June 22, 2005 12:03 PM
> Subject: [aprssig] Packet routing, path specification.
>    I keep coming back to the desire that the network manage 
> itself, and minimize or eliminate the need for the end-user 
> to know the topology of the network in the neighborhood they 
> just happen to be passing thru.

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