ID/NOID AND WHY ALL APRS DIGI's SHOULD BE NO-ID! 29 Oct 2001 --------------------------------------------------------------------------- WB4APR All APRS DIGI's should be set with the UIFLOOD WIDE,28,NOID. They should never be set to "ID" or if they are, then they should be clearly marked, since they will screw up the interpretation of APRS path data. This missunderstanding has been with us since 1998, and it NEEDS TO BE FIXED. Here was my latest attempt at educating the owners of DIGIS with the "ID" parameter improperly set. > ...From the perspective of a digi operator who is interested in seeing > the network's performance, I really don't care what digi a station > entered the network from. I am more interested in how *I* heard the > station. This is useless information. If you hear it, then you hear it. Done. It is not how you hear it that is important, but *what will hear you* (or what will hear your users)... > When I am in Mississippi or Alabama driving in the > boonies, why do I care what digi heard the originator? He should either > have a proper position entered or else he should be using a GPS. More than half of APRS packets contain no position data. And when one needs to *communicate via message*, none of the packets do. WIth ID enabled, every digi destroys the oritinators original path entry and thus all flexibility in optimizing paths for passing real information (not just posits) is lost. ALso in your ALA/MISS example, *you, the mobile* are the "originator" that may have the biggest interest in knowing what digi heard *you*. ANd one final comment before I turn to the REASONS file and the thing that caused me to raise this topic in the first place. This was while I was a visitor in Atlanta for the AMSAT convention. In that area, most of the digis are set to "ID". While I was there, I monitored 144.39 and could learn nothing about the local network, Every packet for 3 days arrived as XXXXX>APRS,N4NEQ-2*,WIDEn-N:... YYYYY>APRS,N4NEQ-2*,WIDEn-N:... ZZZZZ>APRS,N4NEQ-2*,WIDEn-N:... ad nausium. Yes after the first packet, I could see that I was hearing N4NEQ-2. But the fact that the originators path information was destroyed in the thousands of other packets coming in over 4 states, is what weakens the APRS network. The entire time I was in the city I could gain nothing from the network by monitoring path data. BECAUSE "ID" WAS SET and it was obliterating all other path data! Here is what I wrote the last time this came up: WHY UIFLOOD WAS DESIGNED TO DEFAULT TO NOID: The setting of ID has always been very controversal because it is NOT how APRS WIDEn-N digipeating was designed to work. When new digi owners in the West were the first to start putting up WIDEn-N digis, they thought it made sense to turn ID on. It took years to get them to understand that that is not the intent, was not the design, and was not how WideN-N is supposed to work. The default for the UIDIGI command is NOID. That is how it is supposed to work. Notice, that slowly but surely most regions of the country have now switched back to NOID. And now, finally Jeff Brenton changed his recommendations on the dididahdahdidit web page so that this confusing information is finally out of the way. Here is the rationale for three very reasonable USER paths: A) VIA WIDEn-N User chose shortest possible path B) VIA DIGI1,WIDEn-N includes originating digi for return path info C) VIA WIDE,WIDEn-N Same as B, but user is not sure of his digi D) VIA RELAY,WIDE Same as C, but user may need to use a home stn. Now lets look at how these are displayed after going through a WIDEn-N digi, (lets call it DIGIZ) with each of the two settings of ID and NOID: If ID is set: A) WIDEn-N arrives as DIGIZ*,WIDEn-X making all packets longer B) DIGI1,WIDEn-N arrives as DIGIZ*,WIDEn-X and source info is lost C) WIDE,WIDEn-N arrives as DIGIZ*,WIDEn-X and source info is lost D) RELAY,WIDEn-N arrives as DIGIZ*,WIDEn-X and source info is lost If NOID is set. A) WIDEn-N arrives as WIDEn-X preserving shortness B) DIGI1,WIDEn-N arrives as DIGI1*,WIDEn-X and source info is kept C) WIDE,WIDEn-N arrives as DIGI1*,WIDEn-X and source info is kept D) RELAY,WIDEn-N arrives as DIGI1*,WIDEn-X and source info is kept Thus, the NOID setting preserves the original intent of the sender. The ID setting destroys the intent of the sender. THus having NOID set is the way APRS WIDEn-N digipeating was designed. It has many,many advantages: 1) It preserves the intent of the sender 2) It preserves the source digipeater always 3) It allows everyone to see their OUTGOING path successes. (It is the success of your OUTGOING path that determines your ability to communicate, not your incoming path). 4) It allows tracking any TNC without a GPS or position data to the nearest digipeater anywhere in the world. I can build a cigarette pack sized TNC tracker (with no GPS) that will wake up and send a packet once an hour for a YEAR on 4 AA batteries. I can track it anywhere in the world if digis use NOID. Because I can always see which digi HEARD IT first. Compare that to a tracker that can only last 5 hours on the same 4 AA batteries because of the GPS.. 5) It allows reverse pathing for sending back efficient messages. All I need to see is ONE packet from you and I can see what digi you are near. Even without any POSITION info from you, I can look at a map, see where that digi is, and send you back a reply. 6) If a person uses a HOME digi to get out of a canyon or a building in an "ID" network, no one will ever be able to send him anything, because they do not know that they must include WIDEn-X,HOME as the return path. Conversly, In a NOID network, his packets all arrive everywhere as HOME,WIDEn-X so everyone knows you must reverse the path via WIDEn-X,HOME to get back to him... Note, the ONLY advantage of "ID" is so that you can see what your local digipeater is. But Geeze. That is easy. And not worth the destruction of all other path data... If you want to see what your local digi is, send a packet via WIDE and it should come back with its callsign inserted. Please consider changing your digis to the way WIDEn-N was designed and intended and all of its advantages... Thanks! But I am no longer being emotional about this. If you have good reason to have set ID, then at least mark those digis with the "I" overlay so that users will know how to interpret packets in your area. Because without this knowledge, then the following packet can mean two totally different things: WB4APR,DIGIX,WIDE3-2:Anybody copy? Did it begin in a NOID network with the first hop of DIGIX? or did it end in an ID network via the last hop of DIGIX? Thanks, for your consideration... Bob, WB4APR