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ZL3AI > APRDIG 14.05.04 21:08l 154 Lines 5802 Bytes #999 (0) @ WW
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Subj: TAPR Digest, Apr 27, 2/2
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: Re: timeslotting on 30m
From: "K. Mark Caviezel" <kmcaviezel@yahoo.com>
Date: Tue, 27 Apr 2004 08:07:10 -0700 (PDT)
X-Message-Number: 9
WB4GQK:
timeslotting is *exactly* the remedy for deaf trackers if there was any
'disciple and order' to it. What you've described sounds like a bit of a
free for all.
Maybe it's too late to change, or possibly things could evolve to enable
timeslotted 30m APRS transmitters to co-exist. Maybe an alternate frequency
on 30 m could be employed, with gentlemen's agreements about who would
transmit and when- a 'clean sheet from day one' if you will. Because of
different needs, users could request 1 slot per hour or 2 or 3 or 4. An
alternate frequency for VHF APRS would be crippling and divisive, getting
away from the 'local, tactical, real time' maxim that Bob wants. HF APRS
has capability to be not local at all, but going to an alternate
'timeslotted from day one' scheme is not necessarily divisive because only
a handful of I-gates could provide north american coverage. As soon as I
get my home station online I may bird dog this some more.... but I'm not
in a rush.
- KMC ac0ak
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Subject: digipeater naming conventions
From: wes@johnston.net
Date: Tue, 27 Apr 2004 11:22:13 -0400 (EDT)
X-Message-Number: 10
How feasible is it for us to name our digipeaters by our FIPS code? Yes,
that would limit us to one main digipeater per county, and FIPS is a
US-centric numbering system.
As far as having more than one digipeater per county, I wonder if we could
use the 5 digit version of a FIPS code (remove the first 0) and append the
letters A-Z on the end. For example, Sumter SC is 45083, so the two
digipeaters here in town would be named 45083A and 45083B.
This would require that each digipeater ID every 10 minutes with it's real
callsign, but that it's a problem since we tend to learn towards a network
cycle time of 10 minutes anyway. The old PBBS systems used aliases and
ID'ed every 10 minutes too, so this is a well established legal method of
operation.
My reasoning for this is that there is no geographic representation of our
digipeaters at this time. Since we run NOID predominately, we know the
entry point into the network, but we have no idea WHERE that is. Do you
know where kd4rdb-2 is? But I bet if you knew fips codes, you'd know where
45085 was. And although you might not recognize the county number, you
might stand a chance knowing 45 was south carolina.
I am beginning to think about a routing method.. and this is a part of it.
Wes
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Subject: Call For Papers: DCC 2004
From: "Ford, Steve, WB8IMY" <sford@arrl.org>
Date: Tue, 27 Apr 2004 10:54:47 -0400
X-Message-Number: 11
The 2004 TAPR/ARRL Digital Communications Conference will be held
September 10-12 at the Airport Holiday Inn in Des Moines, Iowa. You'll
find more conference information on the Web at http://www.tapr.org/dcc/.
We are now accepting papers for the conference proceedings. You do NOT
have to be present at the conference to have your paper included in the
proceedings.
Please send your submission by August 10 to:
Maty Weinberg
ARRL
225 Main St
Newington, CT 06111
or via the Internet to:
maty@arrl.org
73 . . . Steve Ford, WB8IMY
QST Editor
ARRL Publications Manager
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Subject: AX.25 Spec question
From: wes@johnston.net
Date: Tue, 27 Apr 2004 13:10:47 -0400 (EDT)
X-Message-Number: 12
I found this in the ax25 2.2 pdf file....
3.12.4. Layer 2 Repeater Address Encoding
Evolving consensus opinion is that repeater chaining belongs to a higher
protocol layer. Consequently, it is being phased out of Layer 2, although
backward compatibility is being maintained with a limit of two repeaters.
If a frame is to go through Layer 2 amateur packet repeater(s), an
additional address subfield is appended to the end of the address field.
This additional subfield contains the callsign(s) of the repeater(s) to be
used. This allows more than one repeater to share the same RF channel. If
this subfield exists, the last octet of the source subfield has its address
extension bit set to 0, indicating that more address-field data follows.
The repeater address subfield is encoded in the same manner as the
destination and source address subfields, except for the most-significant
bit in the last octet, called the H bit. As discussed in section 3.12.1,
the H bit indicates whether a frame has been repeated or not.
*************************************************
Does this mean that the general direction of future AX25 specs will only
allow two digipeaters to be specified in the path? I'm confused about why
this would need to be limited.
Wes
ham callsign: kd4rdb
find me: http://wesvan.zapto.org
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Subject: Re: AX.25 Spec question
From: "Scott Miller" <scott@opentrac.org>
Date: Tue, 27 Apr 2004 10:20:37 -0700
X-Message-Number: 13
I think this change was made without taking APRS into account. However, I
can't really disagree with its intent. I don't think support is going to go
away any time soon, but people are already looking at alternatives.
PE1RXQ came up with a set of proposed OpenTRAC elements to handle APRS-style
routing, and wrote a test implementation of a digipeater to use them. The
basic path element only requires a couple of bytes to specify any of the
usual RELAY, WIDEn-n, and TRACEn-n paths.
Couple something like this with the proposed minimalist AX.25 frame type and
you could cut a bunch of cruft out of your packets.
Scott
N1VG
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