[aprssig] SSn-N Organizational boundaries
bruninga at usna.edu
Fri Nov 30 01:05:49 EST 2007
> Since the population density of Europe is,
> on average, far higher than most of the US,
> it makes sense to segment Euro SSn-N regions
> to areas smaller than an entire nation...
Just to be very clear. Sorry to repeat myself....
We are not after geographic boundaries or political boundaries. The segmentation into SSn-N or SSSn-N is intended to be purely along COMMUNICAION ORGANIZATION boundaries.
The purpose of SSn-N (or SSSn-N) is to provide a "means" and also a "LIMIT" so that those top-level communications organizatiosn may at times comunicate throughout their entire communications area of responsibility (without flooding areas beyond their interest)..
Of course, it turns out, that in most cases, these top-level amateur radio organizational boundaries usually do match political and geographic boundaries because those are the people, areas and agencies they serve. But that is a coincidence.
So when I used WPA and EPA as examples for Western PA and Eastern PA, it was not because those are two ends of a long state, it is because those are the actual designations for the two ARRL SECTION organizations in that state.
When the SECTION Manager of WPA wants to send out an emergency bulletin to his WPA APRS organization, he could use the path of WPA7-7 and A) Know that he used the best path to cover all of his area, while also B) Knowing that he did not flood any QRM outside of his area.
And there is nothing wrong with SS7-7 in these types of situations; for example, in Maryland, although MD3-3 from the middle of the state would hit all 15 digis in the state, but it takes MD5-5 for someone at one end of the state to hit all the other Maryland Section members during a MD emergency net. But since MD3-3, or MD5-5 both hit the same 15 digis and no farther, then there is nothing wrong with using MD7-7 either. It still hits the same 15 digis ONCE.
SO again (repeating myself)... SSn-N is only intended for AREA WIDE organizational (rare) emergency and Nets that require AREA-WIDE commmunications. In that case, usually SS7-7 will always work and will not cause any real problems.
TRACEABLE SSn-N! Lastly, remember that SSn-N is NOT traceable (in the KPC-3's) because we are using the TRACEABLE routing for WIDEN-N, therefore SSn-N as implemented can only identify the LAST digi in the path. SO here are TWO OPTIONS:
1) Use SS7-7 for the most efficient and shortest packets but NOT traceable, and hard to figure out two-way paths.
2) Use SS1-1,SS6-6 for TRACEABLE paths if 2-way messaging will be involved or you want to have traceable paths. The packets will arrive everywhere with the FIRST and LAST digis identified.
Hope that is helpful...
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