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[aprssig] Tier 2 Status

Steve Dimse steve at dimse.com
Thu Jun 22 03:04:37 UTC 2006


On Jun 21, 2006, at 10:16 PM, AE5PL Lists wrote:

>> -----Original Message-----
>> From: Steve Dimse
>> Posted At: Wednesday, June 21, 2006 8:45 PM
>> Subject: Re: [aprssig] Tier 2 Status
>>
>> On Jun 21, 2006, at 7:57 PM, AE5PL Lists wrote:
>>
>>> There are over 5,000 stations (IGates, clients, and
>> servers) directly
>>> connected to APRS-IS.
>>
>> Ummm, this number seems awfully high. How do you arrive at
>> this? In the last hour, the number of position reports
>> received by findU is 9233. This includes objects, weather
>> warnings, and earthquakes.
>
> When you take a myopic view of things, I can see where you would
> misinterpret numbers.  I am looking at a 30 day database based on qac
> and qax q-constructs which means that my number is low.

Do you need capacity the number of people that connect to the APRS in  
a 30 day period, or do you need to support those that connect at the  
same time (plus a reasonable excess margin and redundancy). For  
example, there have been 2205 CW reports in the last hour, but these  
connect every 5 to 15 minutes, send data for a couple seconds and  
disconnect. Do you need to have capacity for each of them to be  
connected constantly?

I can see where you got that number if you are using the q's, but the  
great majority of those will be CW connections that are simply not  
the same as a 24/7 IGate! Call me myopic if you want (it is true, and  
I do not believe laser eye surgery has adequate followup yet!) but if  
you think the APRS IS needs to have a dedicated connection for  
everyone that connects once a month, you are grandiose! We should be  
talking about the maximum number of simultaneous connections, not the  
number of people spread out over a long, arbitrary time frame.
>
>> To add each server to the core, a new person would need to
>> edit their config file to match a template, and start the
>> javAPRSrvr program.
>
> ???  Steve, I understand how a mesh works.  What you conveniently  
> forget
> is that the load does not evenly spread out and the issues of
> _coordinating_ those servers becomes exponentially more difficult.

Where's the exponent? The problem is linear, n servers equals n  
sysops, each of whose hub has n-1 connections to other hubs. If  
managers where really afraid of linear increases in complexity, we'd  
all still be living in villages!
>
>>> and getting then necessary OC-3 pipes with high pps routers
>> donated is
>>> unlikely as well.
>>
>> I disagree strongly with this statement. As I said, I have
>> had no problems getting such sites donated every time I have
>> asked. There are a lot of APRS users that control sites with
>> fat pipes.
>
> Glad you disagree.  Gee, if my number of 5000 was high and you think
> there are maybe only 1000 direct APRS-IS users,

If you are talking about the number of APRS (not CW) users, I'd say  
even less.

> and 1% work for ISPs (a
> generous percentage)

And one I have no estimate for, other than working from the other  
end, the number which actually deliver...

As I say, EVERY time I have needed a site, I've gotten multiple  
offers from very good sites, people that in fact do have total  
control (like CTOs of large co-lo sites). Every offer I have accepted  
has turned out to be real (and don;t think I don;t lose a little  
sleep shipping an $8k server to someone I never heard od before!) So  
whatever the percentage is, it is adequate.

Again, I am not trying to convince you, or anyone else. I do believe  
that the two tier system is inefficient, and my purpose in jumping in  
here was to make it clear this is not the way I designed the system,  
and that I do believe it could be run more logically as a single core  
system.

The fact is, it does work, and well. I just want to be able to say "I  
told you so" when it stops working ;-)

Steve K4HG




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