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

Bill Vodall wa7nwp at jnos.org
Wed Jun 22 14:18:39 UTC 2005


On Wed, 22 Jun 2005, Robert Bruninga wrote:

> >>> <maiko> 06/21/05 3:06 PM >>>
> >NOSaprs now provides customized crossport 
> >digipeating... if we get:   HFUSER>APRS,WIDE
> >on HF, we can direct it to go out on VHF as :
> >     HFUSER>APRS,N1OHX*,WIDE3-3
> 
> 1) It is a 3 hop path that is not welcome in
> most high density areas of the APRS system

It's just an example..   Granted it should be shorter.

> 2) It violates the fundamental principle that
> the network should not modifying the path or
> intent of the sender except to protect the
> network from abuse. (or in response to a 
> request from the sender).

It's not.  It's sending the packet on a different
network.  The original has been unchanged.  This
is a good technique to expand the system and make
a little use of our vast underutilized frequencies.
As mentioned later - it should be in 3rd party format.

> 3) This path modification expands its load on
> the network adding to network congestion

Different network -- thus different rules for the path.

> 4) HF gates have the potential to add lots of
> added load to local networks.  It has always been

Spotty 300 baud is adding "lots" to 1200 baud.  The
years I gated 10.151 to 144.39 here -- the number
of packets were insignificant.

> the solid receommendation that HF packets should
> not go more than one hop on VHF so that that
> added congestion remains in the "backyard" of
> the HF gate and only impacts his local net, and
> not any surrounding states or nets that simply
> do not want it.  APRS loads should be managed
> at the local level and this becomes impossible

"the local level" - that's the key.  In some areas
even zero hops would be bad.  In other areas, Wide3
might be welcome.  The important thing is we
have the technology to do this.

> when large packet sources like HF gates and
> IGates spew their trafffic out more than generally
> 1 hop in all directions.

HF gates are certainly not in the same category
as IGates..

> 5) The only time (IMHO) that the network should
> modify the original packet of a sender is to:

> b) When removing APRS packets from the APRS
> system and placing them in another system and
> then only in a 3rd party format so that the 
> originators intent and original packet remains
> intact.

This is a big thing.   I've had "3rd party format" on
the wish list for Digi_ned for years for just this
reason.   When I was gating 10.151, it was essentially
as a one-way system bringing in the traffic for information
purposes only.   I didn't want the system to consider my
HFgate as a return path.  Yet since there was no way to
do 3rd party format, I became a bogus route to the 30 meter
stations.

I'll be talking to Maiko about the 3rd party format as
an extention to the NosAPRS gating.

Maybe this isn't such a good time to bring up my "need" to
actually change the data payload of packets when gating
them between networks...   :-)


Bill





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