Re: [DSTAR_DIGITAL] callsign routing

Nate Duehr Fri, 16 Oct 2009 13:41:57 -0700

The information is in a table on the local GW that's updated
periodically from the central Trust Server.  The user radios
aren't involved at all, other than sending the callsign(s)
required.

The local GW's don't update often enough to make jumping from GW
to GW always feasible. Various update times have been used over
the "history" of D-STAR all the way back to Gateway v1 software.
Right now, I believe it's about 5 minutes, but don't quote me on
that. I lost interest in chasing this design flaw by trying to
change timing values, long ago, because it's not the right way to
fix it.

So, right now, if you hit it at "the right time", when a GW has
just updated from the Trust Server, it'll seem quick. If you
switch GW's right after an update, you're "stuck" until the next
update, though. Catch-22.

To do it closer to "real-time" would probably require a re-design
of the GW/Trust Server environment. Right now, all GW's update
constantly. This is not the correct way to design a system for
growth. It's called a "centralized" or "clearinghouse" design
methodology, and puts heavy load on the central servers doing
updates that no GW actually needs.

To do it differently, updates should be dynamic and pulled only
when needed, but announcements made of users moving between
systems (which isn't ALL that common, so traffic of that type
would be very low, overall)... thus, available immediately if a
user switches GW's.

Better yet, the best design for this type of network would be to
decentralize the whole thing, with the only data necessary in a
centralized location being the list of GW's, and have GW's query
each other, directly. Similar to DNS.

In fact, it could all be done with DNS TXT records with the
NOTIFY feature of bind. No need to have an RDBMS at all, nor
take the performance penalty of having to run an entire RDBMS
engine for the tiny number of records that actually need to be
"known" at any one time, by each GW.

Bind even has DNSSEC if someone were worried about security. All
traffic in the network of machines could be encrypted.

Anyway, making it work right would be easy. Plenty of other ways
even if not done with BIND.

Getting the politics done to get Icom to change it? I have no
dog in that fight.
--
Nate Duehr, WY0X
n...@natetech.com

On Wed, 14 Oct 2009 19:40 -0400, "Fran Miele"
<f...@miele-family.com> wrote:

I frequently talk with my son in Dallas, N1GAT and use call sign
routing as he does when he calls me. The questions I have are:
where is the information stored that is used for his radio to
find which repeater I last transmitted? How long does it stay
there? How long does it take to update?

I have noticed a couple of things. Sometimes when he calls me I
am on one of our repeaters that is linked to a reflector so I try
not to talk with him there. I usually go to our stand alone
repeater, transmit there and then wait for him to call. However,
sometimes he calls me before I have switch. So I tell him to
wait, I switch repeaters and call him. On some occasions the
switch is almost instantaneous and sometimes it takes a while. In
fact one night I switched before he called and his call to me
still went to the other repeater, not the one I had last
transmitted on 30 minutes earlier.

Fran

References

Re: [DSTAR_DIGITAL] callsign routing

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