[aprssig] APRS-IS core Servers - THANKS!

[Robert Bruninga]

And everyone that contributes is AMAZING!



Imagine, an all-volunteer network held together by extremely dedicated
volunteers and contributors.

Spanning the globe…  all for APRS.



Thanks!

Bob Bruninga, WB4APR





*From:* aprssig <aprssig-bounces at lists.tapr.org> *On Behalf Of *Tom Hayward
*Sent:* Thursday, August 16, 2018 8:36 PM
*To:* aprssig at lists.tapr.org
*Subject:* Re: [aprssig] APRS-IS core Servers



On Thu, Aug 16, 2018 at 2:34 PM Steve Dimse <steve at dimse.com> wrote:

> Could someone tell me what the APRS core servers are needed for?
> On the websites of some core servers I saw that some people connect to
them instead of connecting there stations
> to Tier2 servers. But I think they could switch to Tier2 servers easily.
>
This question will open old wounds and probably start a few arguments, but
here we go.

The question you should ask is "Why Tier 2?"



Well, it's clear which side Steve is on.



The current Tier2 design was implemented during a period when there were
often no free slots. I believe there were only three or four core servers
at the time and each had a max connection limit of around 200. There were
more than 600 hams/igates on APRS at the time (I believe the total was
around 2k), so at peak times there would be no free slots to connect. By
implementing "hubs" in Tier2, the Tier2 servers could continue to exchange
packets even if they could not connect to core.



Since then, more core servers have been deployed, and many have had their
max connection limits increased (due to more capable hardware and more
efficient software).



Another nice feature about Tier2 is that the rotate addresses are
dynamically built with input from healthchecks. They only include the best
8 servers at the time, and servers are frequently swapped in and out of the
list due to number of free slots, downtime, or increased latency.



Tom KD7LXL
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