[aprssig] Documenting the APRS Generic Digipeating spec?

spam8mybrain spam8mybrain at yahoo.com
Thu Jan 5 15:00:31 CST 2017


From reading the specs, the generic and New-N paradigm digipeating aren't documented anywhere in the AX.25 specifications. AX.25 Version 2.2 is so old, it predates RELAY and WIDE, let alone the New-N paradigm. And would connected-mode packet work reliably with redundantly responding digipeaters?
So any spec would have to clearly note that generic digipeating and its successors of New-N, viscous, and preemptive digipeating do not apply and should not be used for I and S frames (and possibly not for other subtypes of U frames besides UI), aside from the issue of deprecating 1st generation generic digipeating (RELAY/WIDE/TRACE).
Your webpage seems to be a good starting point for 2nd gen generic digipeating.
Andrew, KA2DDO

-------- Original message --------
From: Robert Bruninga <bruninga at usna.edu> 
Date: 1/5/17  3:18 PM  (GMT-05:00) 
To: TAPR APRS Mailing List <aprssig at tapr.org> 
Subject: [aprssig] Documenting the APRS Generic Digipeating spec? 

APRS Authors: We all came up with the “Generic-digipeating” concepts for APRS in 1995 or so and is pretty well established in most modern TNC’s  But its been so long and maybe I am having a senior moment, but I am drawing a blank in trying to think where it is actually documented in AX.25!??  The APRS spec only addresses the data formats (and the use of the AX.25 Destination callsign field in its non-standard way).  The APRS spec (I don’t think) addresses any of the generic digipeating techniques used. I think we need to nail this down by spec, since there are some weird implementations that cause confusion.  And if there are new ideas we want to add, then we should have a documented baseline starting point. We could call it AX.25-UI for clarification. My source for how this all works is my decade old http://aprs.org/fix14439.html web page.Is there another better starting point for extracting exactly what UI digipeating is? Or am I having a senior moment? Bob, WB4APR
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