SSn-N Values


Lynn Deffenbaugh
 

James,

Very well stated and it matches my understanding of the paradigm as well. Rest easy, the reason I'm looking for such a list has nothing to do with APRSISCE/32!

As I mentioned in an earlier post, I also tinker around with analyzing the APRS infrastructure by watching packets from all over North America and trying to make sense out of the paths. Your standard of putting the aliases into the beacon status text is really good for humans looking for what is supported in a given area. However, software doesn't have the reading ability of a 2 year old let alone the ability to interpret the various ways operators code such information for humans.

Consider a digiS that uses tactical callsigns of CNABAR, HARIN, LEWIS, PEQUOP, and VIC. Suppose further that someone decides to use an SSn-N alias of PIPEn-N (anywhere from 1-1 through 7-7 as in your example). And to complicate matters, someone half-way around the world decides to call their special event stations PIPE1, PIPE2, ..., PIPE7, PIPE8, and PIPE9 (maybe they're a pipe-rolling event). Consider the paths of packets that have gone through the various digis and gotten marked used, especially the SSn-N aliases that are used up.

How can you tell the difference between
.....>.....,CNABAR,HARIN,PIPE2*.... and
....>.....,PIPE2*,WIDE2-1..... especially when PIPE2 IDs itself as
PIPE2>APXXXX:

Did the first packet really go through PIPE2 the station or is there really a PIPEn-N running around?

My analysis software had this trouble even with WIDE1 and WIDE2 when people mis-configure their stations and accidentally make that their MyCall. I finally decided that WIDEn-N is well known and coded around it. I am now trying to determine if the SSn-N aliass have a "well known" list somewhere or whether they're only local word-of-mouth information. Apparently, it's more the latter (except that it's word-of-digi-comment).

Anyway, I'll let the list get back onto APRSISCE/32 topics now that I've chased this rabbit into the briar patch...

Lynn (D) - KJ4ERJ - Author of APRSISCE/32 and APRS Infrastructure Visualizer

PS. I finally decided that I'll just ignore "impossibly long" digi paths and let the rest of the routes land where they fall.

PPS. To see some of the graphs of which I speak, go to

http://tinyurl.com/APRSAct24 or http://tinyurl.com/APRSAct00



James Ewen wrote:

On Wed, Mar 3, 2010 at 12:45 PM, Lynn W. Deffenbaugh <kj4erj@arrl.net> wrote:


We've all become familiar with WIDE1-1 and WIDE2-1 or WIDE2-2, but the
SSn-N path aliases don't seem to have any other description other than
on that page (at least, from what I've been able to find).
What exactly are you looking for Lynn? A list of specified values for
SS? There isn't one. The concept is to use the two letter abbreviation
for the state/province. In some areas they use a 3 letter
abbreviation, such as Northern California (NCA).

If one wanted to, they could organize a group of digipeaters that
responded to a totally unique SS value, such as BOINKn-N... as long as
the alias fits the packet name type properly, it's good. It would be
up to the locals to publish the local SSn-N path to use, as they see
fit.

That's why we send that information in the position packets from our
digipeaters around here. W3, ABn, Edmonton, VE6SBR is what the main
digipeater in Edmonton sends, telling people that it supports up to 3
hops via WIDEn-N, the local SS alias is AB, the digipeater is in
Edmonton, and the IC assigned callsign is VE6SBR.

The value of SS doesn't even need to be supported by all the
digipeaters in a specific area. It could be possible to implement a
pipeline of digipeaters between two areas that respond to a special
alias, which would allow people to send packets between to very
disparate areas along a specialized path, without having to flood the
whole area. I could conceivably set up a string of digipeaters between
Edmonton, and Seattle that use an SS alias of PIPE. By sending a
packet with a path of PIPE7-7, I could get that packet to follow the
route on the specific digipeaters that respond to PIPEn-N, getting the
packet to the far end without lighting up any other digipeaters
between Edmonton and Seattle.

So, having said that, I'm still wondering why you are looking for a
definitive list of SS values.

James
VE6SRV


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