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Date: Sun, 17 Sep 00 16:38:55 MET
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From: pa2aga@pe1mvx.ampr.org
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Ham-Digital Digest Sun, 17 Sep 2000 Volume 2000 : Issue 254
Today's Topics:
APRS-TCP/IP help (8 msgs)
Auctions are like Pawn Shops, was: Beware of W4WWB
Beware of W4WWB
eMail Address For KF7XP(XPWare)??
HF multicast protocols. (6 msgs)
multicast (was internet repeater linking)
TCP/IP Address (4 msgs)
Windows software for an SCS PTC-IIe TNC (2 msgs)
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Loop-Detect: Ham-Digital:2000/254
----------------------------------------------------------------------
Date: Sat, 16 Sep 2000 22:46:56 GMT
From: "D. Stussy" <kd6lvw@bde-arc.ampr.org>
Subject: APRS-TCP/IP help
On Wed, 13 Sep 2000, Ed_Woodrick wrote:
> While TCP/IP supports broadcasts, the Internet does not. There is a
> permutation called multi-cast that is close, but it also isn't widely
> supported. So, to do what you want, you will have to use transmissions to
> all systems that you want to send or receive data from . UDP would probably
> be the protocol that you would use.
I disagree on the protocol. UDP only supports one data packet in each
direction (as in a query and response) before closing the connection. TCP is
what is needed as it can send a session (or a group of packets
bidirectionally)
before closing.
> "Chris" <ckg@osu.edu> wrote in message
> news:ij2vrsk284148lmimmjlhrolku6c5nth9p@4ax.com...
> > I have a very hi-profile packet station, running APRS. The computer
> > that controls the TNC, has an active 100 base-T network connection. I
> > can get a static IP if need be.
> >
> > What I want to do, is "broadcast" all the RF (APRS) data to the
> > internet...and gather all the internet (APRS) data, and "broadcast" it
> > to the RF side.
> >
> > I am starting from scratch, and have no information on this subject.
> > Any help, direction, web sites,lieteture, guidance, etc...would be
> > most appreciated.
------------------------------
Date: Sat, 16 Sep 2000 16:31:00 -0700
From: "Dana H. Myers" <dana@source.net>
Subject: APRS-TCP/IP help
"D. Stussy" wrote:
>
> On Wed, 13 Sep 2000, Ed_Woodrick wrote:
> > While TCP/IP supports broadcasts, the Internet does not. There is a
> > permutation called multi-cast that is close, but it also isn't widely
> > supported. So, to do what you want, you will have to use transmissions to
> > all systems that you want to send or receive data from . UDP would
probably
> > be the protocol that you would use.
>
> I disagree on the protocol. UDP only supports one data packet in each
> direction (as in a query and response) before closing the connection. TCP
is
> what is needed as it can send a session (or a group of packets
bidirectionally)
> before closing.
I believe you're mistaken. UDP is an unreliable datagram service that makes
use of IP fragmentation and reassembly. You can open a UDP socket (there's
no connection to speak of, just an end-point for the demultiplexing) and send
as many frames as you'd like.
It's not transaction based like you describe, at least not at the protocol
level. There may be implementations of UDP APIs that are broken, of course.
Dana K6JQ
dana@source.net
------------------------------
Date: Sun, 17 Sep 2000 00:36:12 GMT
From: "D. Stussy" <kd6lvw@bde-arc.ampr.org>
Subject: APRS-TCP/IP help
On Sat, 16 Sep 2000, Dana H. Myers wrote:
> "D. Stussy" wrote:
> > On Wed, 13 Sep 2000, Ed_Woodrick wrote:
> > > While TCP/IP supports broadcasts, the Internet does not. There is a
> > > permutation called multi-cast that is close, but it also isn't widely
> > > supported. So, to do what you want, you will have to use transmissions
to
> > > all systems that you want to send or receive data from . UDP would
probably
> > > be the protocol that you would use.
> >
> > I disagree on the protocol. UDP only supports one data packet in each
> > direction (as in a query and response) before closing the connection. TCP
is
> > what is needed as it can send a session (or a group of packets
bidirectionally)
> > before closing.
>
> I believe you're mistaken. UDP is an unreliable datagram service that makes
> use of IP fragmentation and reassembly. You can open a UDP socket (there's
> no connection to speak of, just an end-point for the demultiplexing) and
send
> as many frames as you'd like.
>
> It's not transaction based like you describe, at least not at the protocol
> level. There may be implementations of UDP APIs that are broken, of course.
OK - but all the applications that I have seen which use UDP are either of the
query/response type (such as DNS) or of the unsolicited information type (such
as for dynamic routing). I've never seen nor heard of an application which
takes multiple packets. I thought UDP opens a socket but NOT a stream like
TCP
does. If one wants to create a virtual stream with UDP, it's possible, but
that requires that such be designed into the data structure being transferred.
TCP already handles that intrinsically, but UDP [by itself] doesn't.
------------------------------
Date: Sat, 16 Sep 2000 19:51:53 -0500
From: "Steve Sampson \(K5OKC\)" <ssampson@nospam.radio-link.net>
Subject: APRS-TCP/IP help
"D. Stussy" says:
>
> I disagree on the protocol. UDP only supports one data packet in each
> direction (as in a query and response) before closing the connection.
No.
Go back and re-read the book. It's been to long for you :-)
------------------------------
Date: Sat, 16 Sep 2000 20:12:45 -0500
From: "Steve Sampson \(K5OKC\)" <ssampson@nospam.radio-link.net>
Subject: APRS-TCP/IP help
"D. Stussy" says:
>
> I've never seen nor heard of an application which
> takes multiple packets. I thought UDP opens a socket but NOT a stream like
TCP
> does.
> If one wants to create a virtual stream with UDP, it's possible, but
> that requires that such be designed into the data structure being
transferred.
> TCP already handles that intrinsically, but UDP [by itself] doesn't.
In simple terms, TCP is a connection oriented protocol that is reliable. You
would
want to use this for reliable things like a database connection, Telnet, etc.
To be continued in digest: hd_2000_254B
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