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ZL3AI > APRDIG 21.01.07 22:51l 257 Lines 9658 Bytes #999 (0) @ WW
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Subj: [APRSSIG] Vol 31 #21, 2/4
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From: ZL3AI@ZL2BAU.#79.NZL.OC
To : APRDIG@WW
Message: 6
Date: Thu, 18 Jan 2007 19:42:50 -0700
From: Chris Howard <w0ep_at_frii.com>
Subject: Re: [aprssig] Periodic Disconnects from APRS-IS
Is there any list I can go to that doesn't play dueling banjos?
On Thu, 2007-01-18 at 12:22 -0500, Steve Dimse wrote:
>On Jan 18, 2007, at 10:44 AM, Phillip B. Pacier wrote:
>
>>Ah! One of the main reasons why Tier 2 was created!
>
>Pete's post had nothing to do with Tier 2.
------------------------------
Message: 7
Date: Thu, 18 Jan 2007 18:45:37 -0800
From: "Scott Miller" <scott_at_opentrac.org>
Subject: RE: [aprssig] Periodic Disconnects from APRS-IS
That's why I suggested it'd be useful on high-volume ports. If you're
carrying the full IS feed, you're looking at maybe 100 msec of buffering
time. If it can be supported by the server software, why not reserve a
buffered port?
Scott
N1VG
>-----Original Message-----
>From: aprssig-bounces_at_lists.tapr.org
>[mailto:aprssig-bounces_at_lists.tapr.org] On Behalf Of AE5PL Lists
>Sent: Thursday, January 18, 2007 11:29 AM
>To: TAPR APRS Mailing List
>Subject: RE: [aprssig] Periodic Disconnects from APRS-IS
>
>This has nothing to do with programming language or how TCP works. This
>has to do with what APRS is: a near real-time reporting system, and what
>APRS-IS is: a very basic APRS packet transport system built originally
>on TCP. Yes, it is very inefficient because the Nagel algorithm is
>turned off (nothing to do with what language clients or servers are
>programmed in). The Nagel algorithm has to be turned off if significant
>delays are not to be incurred due to buffering of packets (which is what
>we saw a few years ago before we started turning off the Nagel
>algorithm). Hope this clears up why the protocol is inefficient and why
>it will stay that way when using TCP.
>
>Also, my posts had nothing to do with bandwidth at the server. The
>bandwidth issue I spoke of is at the client and is primarily a
>processing issue in the client software although it can also be
>problematic for limited bandwidth residential configurations.
>
>73,
>
>Pete Loveall AE5PL
>pete at ae5pl.net
>
>>-----Original Message-----
>>From: Scott Miller
>>Posted At: Thursday, January 18, 2007 11:16 AM
>>Subject: RE: [aprssig] Periodic Disconnects from APRS-IS
>>
>>Last time I looked at a TCP dump of an APRS-IS connection, it seemed to be
>>making rather inefficient use of the bandwidth. I saw exactly one line per
>>packet. For slow ports (message only, local filters) this is fine - it
------------------------------
Message: 8
Date: Thu, 18 Jan 2007 18:49:52 -0800
From: "Scott Miller" <scott_at_opentrac.org>
Subject: RE: [aprssig] Periodic Disconnects from APRS-IS
>Is there any list I can go to that doesn't play dueling banjos?
What, with more than 20 hams in one place? Surely you jest! =] Come to
think of it, though, I think every mailing list I'm on has at least one
topic that results in periodic holy wars, regardless of the subject. Human
nature, I suppose.
Scott
N1VG
------------------------------
Message: 9
Date: Thu, 18 Jan 2007 22:11:57 -0500
From: "Stephen Brown Jr" <stephen.brown75_at_gmail.com>
Subject: [aprssig] Setting up a KPC-3+ with a Davis WX station
There is a local ham that is wanting to setup a Davis ProVantage II with a
KPC-3+ to send out WX data back to my QTH to hit my igate and make it's way
to the internet. We attempted this last weekend without success, much of it
due to my own ignorance with this type of setup. Prior to this I have never
put my hands on a KPC-3 or a WX station, certainly has been an enlightening
learning experience.
I understand a little more of what I have to do to get this properly setup,
however, I had still had some questions that I'm hoping someone here with
experience on this can answer.
First a summary of what we are doing:
Just passing WX data, this setup is located on a remote mountaintop with no
phone/internet/cell phone coverage. Radio is the only way we can get the WX
data we need out of there for our local Skywarn folks. Not such a bad thing
:D
With that being said, there will be no digipeater functions enabled. I want
to broadcast the WX data every 10 minutes direct to my station at home
(hopefully we wont have to digipeat it to my house, I think I can hear him
direct, and he has a 4 element yagi pointed directly at me) After reading
about the LT buffers, I think the best way for me to do that is to set the
datalogger unit in the WX station to send data every 5 minutes, and fill two
buffers, sending each buffer every ten minutes (if anyone knows of a more
efficient way as far as timing goes, please, I'm all ears, I'm so new to
this)
Some of my questions. How do I set a path instead of a generic alias? Is
this done through the unproto command? For example, if I just want to send
the data direct back to me, would my unproto be something like APRS via
N1VLV-10? Or if I wanted to digipeat, APRS via KS4NG-7(our local digi that
is closest to me), N1VLV-10?
Another thing, is there a way to set a WX symbol in the TNC itself, or am I
to assume this is passed on from the datalogger in the WX station in the
proper format to be xmitted?
Sorry so many questions and they may be vague.... but completely new to me
and I need some guidance from those of you that have experience in this
area.
tnx and 73's
Stephen
N1VLV
------------------------------
Message: 10
Date: Thu, 18 Jan 2007 20:18:30 -0700
From: Chris Howard <w0ep_at_frii.com>
Subject: RE: [aprssig] Periodic Disconnects from APRS-IS
On Thu, 2007-01-18 at 18:49 -0800, Scott Miller wrote:
>>Is there any list I can go to that doesn't play dueling banjos?
>
>What, with more than 20 hams in one place? Surely you jest! =] Come to
>think of it, though, I think every mailing list I'm on has at least one
>topic that results in periodic holy wars, regardless of the subject. Human
>nature, I suppose.
I guess you're right. But usually it's the trolls vs. the kooks. On this
list we have representatives of the two largest server systems that make
the backbone of APRS-IS. And the guys seemingly hate each other enough to
ditch data... my data, into the bit bucket rather than communicate with
each other.
Somewhat less than comforting. If I were paying for the service I would be
asking for my money back.
Chris Howard
w0ep and CW0078
------------------------------
Message: 11
Date: Thu, 18 Jan 2007 20:53:15 -0700
From: Joel Maslak <jmaslak-aprs_at_antelope.net>
Subject: Re: [aprssig] Periodic Disconnects from APRS-IS
On Jan 18, 2007, at 7:42 PM, Chris Howard wrote:
>Is there any list I can go to that doesn't play dueling banjos?
I doubt it.
But I share your frustration. I'm about to pack up my IGate, I shouldn't
need to choose political sides simply to enjoy a hobby.
------------------------------
Message: 12
Date: Thu, 18 Jan 2007 22:14:01 -0600
From: "AE5PL Lists" <HamLists_at_ametx.com>
Subject: RE: [aprssig] Periodic Disconnects from APRS-IS
This is not an issue of computer buffering but of TCP buffering. We found
the Nagel algorithm to be severely harmful to the APRS type of traffic as
was born out by the substantial delays (seconds, not milliseconds) that
were seen a few years ago before we disabled it. Again, this is not an
issue of programming technique or trying to optimize an unknown TCP stack
(yes, every OS implements the stack differently), it is an issue of passing
a near-real-time protocol without delays which can induce loops, among
other issues. This has been explored from many angle and eliminating
buffering was the only solution to keep APRS-IS stable and representative
of the information it is carrying. Once again, the bandwidth involved is
minimal and a _non-issue_.
APRS software authors, PLEASE DO NOT use buffering on your APRS-IS TCP
sockets (set the socket to TCP_NODELAY). All buffering has caused in the
past is problems because the APRS protocol is meant for immediate (not
delayed) delivery. Assuming that the minimum buffering time is the maximum
buffering time is not understanding how the Nagel algorithm works and I
recommend you review the extensive studies on this subject that have been
done on protocols similar to APRS.
73,
Pete Loveall AE5PL
pete at ae5pl.net
>-----Original Message-----
>From: Scott Miller
>Posted At: Thursday, January 18, 2007 8:52 PM
>Subject: RE: [aprssig] Periodic Disconnects from APRS-IS
>
>That's why I suggested it'd be useful on high-volume ports. If you're
>carrying the full IS feed, you're looking at maybe 100 msec of buffering
>time. If it can be supported by the server software, why not reserve a
>buffered port?
------------------------------
Message: 13
Date: Thu, 18 Jan 2007 22:42:47 -0600
From: "Kurt A. Freiberger" <kurt_at_badgers-hill.net>
Subject: Re: [aprssig] Periodic Disconnects from APRS-IS
Amen!
Can I mention Hitler now? Please?
I can't remember when I have had to wade through such unmitigated
h*rs*sh*t. Makes me long for the sohpisticated useNet crowd.
Chris Howard wrote:
>Is there any list I can go to that doesn't play dueling banjos?
>
>On Thu, 2007-01-18 at 12:22 -0500, Steve Dimse wrote:
>>On Jan 18, 2007, at 10:44 AM, Phillip B. Pacier wrote:
>>
>>>Ah! One of the main reasons why Tier 2 was created!
>>Pete's post had nothing to do with Tier 2.
--
Kurt A. Freiberger Austin, TX kurt_at_badgers-hill.net
Amateur Radio Callsign WB5BBW AIM Handle: WB5BBW
"Reputation is what other people know about you.
Honor is what you know about yourself."
- Lois McMaster Bujold - "A Civil Campaign"
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