Mode for Best Throughput?
 

Hello Everyone,

I'm very new to packet radio/digital communications and am trying to climb
up the learning curve too fast. It hurts :-) My question is: What
protocol/mode will give me the best data throughput using 9600 baud packet
on VHF or UHF? Using standard AX.25 protocol in connected mode I'm able to
achieve about 1000 baud throughput. Unconnected I can get about 4000 baud,
but of course that is without any error checking or correction. I'd like to
get maximum data transfer between two stations...network operations are
secondary. I'm guessing using KISS mode would allow me to get better
throughput because of the lack of AX.25 overhead, but I'm pretty clueless on
how to actually do anything with KISS mode. How do I implement something
like TCP/IP over radio? Is that any better than AX.25? Less overhead?
I've downloaded JNOS, but I'm not sure what exactly it is or what to do with
it. Any suggestions or help would be appreciated. I've searched the web
for info on running different protocols in KISS mode, but everything I find
seems like it was written for computer scientists in the 1980s.

Thanks!

Andy KB9JOZ

Well for one simple thing you set your "MAXFRAMES" to 7.
Set PACLEN to 255. That wont change your baud rate but providing
signals are good it will give you the max thruput on msg traffic.
Joe/ABM6JF


************************************************** **
* Ham KH6JF AARS/MARS ABM6JF QCWA WW2 VET WD RADIO *
************************************************** **

Well for one simple thing you set your "MAXFRAMES" to 7.
Set PACLEN to 255. That wont change your baud rate but providing
signals are good it will give you the max thruput on msg traffic.
Joe/ABM6JF


************************************************** **
* Ham KH6JF AARS/MARS ABM6JF QCWA WW2 VET WD RADIO *
************************************************** **

Hi Andy

I started typing this and realised you said "packet" protocol. Thought I'd
leave it in (below) anyway!

- Assuming you want max throughput on a dedicated channel and dont care
about long TX times
- Make sure your maxframes is something huge (7 is max)
- Get your paclen as long as you can. Although 255 is the normal maximum I
did some experiments at 768 some years ago (max for my TNC2 in KISS mode)
- Get your TXDelay and TXTail as small as it can go.
- Make sure your error rate from low signal/interference/over deviation etc
is nil
- Compress the data stream (grin)

Kiss mode by itself doesnt give you better throughput. It simply makes the
TNC a little more "dumb" and allows the host to control it more/better.
TCP/IP (I think) over packet adds a little more overhead to the packet
length so AX25 "connected" mode is likely to be a little faster. I use to
play packet a lot but not for a while. Cant quite remember it all sorry!

I havent seen any implementations using KISS try and send raw data (ie not
AX25 in some form) but I guess that you could certainly modem out a data
stream and have some kind of error correction built into the boxes at each
end. You might be able to use the EC in file transfer protocols like ZModem
but it may get upset at not having a full duplex connection. Might be an
interesting piece of code to write.

Sorry for being short on this. Ask if you want more info.

Cheers

Bob VK2YQA


================================================== ===============
Have a look at Wyman1x. http://www.svs.net/wyman/examples/hdsstv

It is a one way digital code stream with redundancy/checksums built into the
stream. You encode a binary file to a WAV then play it through your radio.

The page above looks like a SSTV piece of sowftare but you can send/recxeive
any kind of digital data. There are some graphs on throughput etc possible

There is code for both Windoze and Linux available

I'm very new to packet radio/digital communications and am trying to climb
up the learning curve too fast. It hurts :-) My question is: What
protocol/mode will give me the best data throughput using 9600 baud packet
on VHF or UHF? Using standard AX.25 protocol in connected mode I'm able
to
achieve about 1000 baud throughput. Unconnected I can get about 4000
baud,
but of course that is without any error checking or correction. I'd like
to get maximum data transfer between two stations...network operations are
secondary. I'm guessing using KISS mode would allow me to get better
throughput because of the lack of AX.25 overhead, but I'm pretty clueless
on
how to actually do anything with KISS mode. How do I implement something
like TCP/IP over radio? Is that any better than AX.25? Less overhead?
I've downloaded JNOS, but I'm not sure what exactly it is or what to do
with
it. Any suggestions or help would be appreciated. I've searched the web
for info on running different protocols in KISS mode, but everything I
find seems like it was written for computer scientists in the 1980s.

Thanks!

Andy KB9JOZ

--


(The reply address is broken. Put bcnoop in front of the at!)

Hi Andy

I started typing this and realised you said "packet" protocol. Thought I'd
leave it in (below) anyway!

- Assuming you want max throughput on a dedicated channel and dont care
about long TX times
- Make sure your maxframes is something huge (7 is max)
- Get your paclen as long as you can. Although 255 is the normal maximum I
did some experiments at 768 some years ago (max for my TNC2 in KISS mode)
- Get your TXDelay and TXTail as small as it can go.
- Make sure your error rate from low signal/interference/over deviation etc
is nil
- Compress the data stream (grin)

Kiss mode by itself doesnt give you better throughput. It simply makes the
TNC a little more "dumb" and allows the host to control it more/better.
TCP/IP (I think) over packet adds a little more overhead to the packet
length so AX25 "connected" mode is likely to be a little faster. I use to
play packet a lot but not for a while. Cant quite remember it all sorry!

I havent seen any implementations using KISS try and send raw data (ie not
AX25 in some form) but I guess that you could certainly modem out a data
stream and have some kind of error correction built into the boxes at each
end. You might be able to use the EC in file transfer protocols like ZModem
but it may get upset at not having a full duplex connection. Might be an
interesting piece of code to write.

Sorry for being short on this. Ask if you want more info.

Cheers

Bob VK2YQA


================================================== ===============
Have a look at Wyman1x. http://www.svs.net/wyman/examples/hdsstv

It is a one way digital code stream with redundancy/checksums built into the
stream. You encode a binary file to a WAV then play it through your radio.

The page above looks like a SSTV piece of sowftare but you can send/recxeive
any kind of digital data. There are some graphs on throughput etc possible

There is code for both Windoze and Linux available

I'm very new to packet radio/digital communications and am trying to climb
up the learning curve too fast. It hurts :-) My question is: What
protocol/mode will give me the best data throughput using 9600 baud packet
on VHF or UHF? Using standard AX.25 protocol in connected mode I'm able
to
achieve about 1000 baud throughput. Unconnected I can get about 4000
baud,
but of course that is without any error checking or correction. I'd like
to get maximum data transfer between two stations...network operations are
secondary. I'm guessing using KISS mode would allow me to get better
throughput because of the lack of AX.25 overhead, but I'm pretty clueless
on
how to actually do anything with KISS mode. How do I implement something
like TCP/IP over radio? Is that any better than AX.25? Less overhead?
I've downloaded JNOS, but I'm not sure what exactly it is or what to do
with
it. Any suggestions or help would be appreciated. I've searched the web
for info on running different protocols in KISS mode, but everything I
find seems like it was written for computer scientists in the 1980s.

Thanks!

Andy KB9JOZ

--


(The reply address is broken. Put bcnoop in front of the at!)

Best protocol for scraping up a bit more throughput at 9.6kb? That would be
RadioMirror, the terrestrial multicast protocol.

At 1.2kb, RadioMirror can move better than 20 MB of data a day. At 9.6kb,
you would do much better than that, of course.

Neither AX25 or TCPIP packet can keep up with RadioMirrors' throughput.
Additionally, RadioMirror is an unconnected mode, so you can distribute the
data to an unlimited number of receiving stations, or just one. That's up to
you.

To investigate RadioMirror, see the "Tutorial" section at USPN:
http://www.uspacket.net and also read the article "Emergency Digital
Communications - Another Angle" in USPN's "Library" section.

These articles represent the single most comprehensive source of information
on setting up and operating this advanced digital mode.

RadioMirror may or may not be right for your application, but it is hoped
that you will enjoy reading about it, in any case. I have tested RadioMirror
at 1.2kb and was astounded at it's ability to move a lot of data quickly.

Good luck!

Charles Brabham, N5PVL
Director: USPacket.Net
http://www.uspacket.net




"Andy Knitt" wrote in message
...
Hello Everyone,

I'm very new to packet radio/digital communications and am trying to climb
up the learning curve too fast. It hurts :-) My question is: What
protocol/mode will give me the best data throughput using 9600 baud packet
on VHF or UHF? Using standard AX.25 protocol in connected mode I'm able
to
achieve about 1000 baud throughput. Unconnected I can get about 4000
baud,
but of course that is without any error checking or correction. I'd like
to
get maximum data transfer between two stations...network operations are
secondary. I'm guessing using KISS mode would allow me to get better
throughput because of the lack of AX.25 overhead, but I'm pretty clueless
on
how to actually do anything with KISS mode. How do I implement something
like TCP/IP over radio? Is that any better than AX.25? Less overhead?
I've downloaded JNOS, but I'm not sure what exactly it is or what to do
with
it. Any suggestions or help would be appreciated. I've searched the web
for info on running different protocols in KISS mode, but everything I
find
seems like it was written for computer scientists in the 1980s.

Thanks!

Andy KB9JOZ

Best protocol for scraping up a bit more throughput at 9.6kb? That would be
RadioMirror, the terrestrial multicast protocol.

At 1.2kb, RadioMirror can move better than 20 MB of data a day. At 9.6kb,
you would do much better than that, of course.

Neither AX25 or TCPIP packet can keep up with RadioMirrors' throughput.
Additionally, RadioMirror is an unconnected mode, so you can distribute the
data to an unlimited number of receiving stations, or just one. That's up to
you.

To investigate RadioMirror, see the "Tutorial" section at USPN:
http://www.uspacket.net and also read the article "Emergency Digital
Communications - Another Angle" in USPN's "Library" section.

These articles represent the single most comprehensive source of information
on setting up and operating this advanced digital mode.

RadioMirror may or may not be right for your application, but it is hoped
that you will enjoy reading about it, in any case. I have tested RadioMirror
at 1.2kb and was astounded at it's ability to move a lot of data quickly.

Good luck!

Charles Brabham, N5PVL
Director: USPacket.Net
http://www.uspacket.net




"Andy Knitt" wrote in message
...
Hello Everyone,

I'm very new to packet radio/digital communications and am trying to climb
up the learning curve too fast. It hurts :-) My question is: What
protocol/mode will give me the best data throughput using 9600 baud packet
on VHF or UHF? Using standard AX.25 protocol in connected mode I'm able
to
achieve about 1000 baud throughput. Unconnected I can get about 4000
baud,
but of course that is without any error checking or correction. I'd like
to
get maximum data transfer between two stations...network operations are
secondary. I'm guessing using KISS mode would allow me to get better
throughput because of the lack of AX.25 overhead, but I'm pretty clueless
on
how to actually do anything with KISS mode. How do I implement something
like TCP/IP over radio? Is that any better than AX.25? Less overhead?
I've downloaded JNOS, but I'm not sure what exactly it is or what to do
with
it. Any suggestions or help would be appreciated. I've searched the web
for info on running different protocols in KISS mode, but everything I
find
seems like it was written for computer scientists in the 1980s.

Thanks!

Andy KB9JOZ

"Andy Knitt" wrote in message
...
Hello Everyone,

I'm very new to packet radio/digital communications and am trying to climb
up the learning curve too fast. It hurts :-) My question is: What
protocol/mode will give me the best data throughput using 9600 baud packet
on VHF or UHF?

Earlier I responded with information about RadioMirror, the multicast
protocol for terrestrial packet that offers truly outstanding
throughput... - But Andy may prefer a connected protocol. In that case,
FlexNet's AX25 stack will give him the best throughput, leaving traditional
AX25 and IP systems in the dust.

A standard TNC has close to 100 different parameter settings that influence
how well the TNC communicates with the computer over the serial link, and
how it performs on the air when hooked up to a radio. Even experts are
sometimes confused by some of the more esoteric link parameters, so many of
these are left at factory default values that are not what you could call
"optimum" but rather represent a compromise.

FlexNet takes full control of all of those link parameters, adjusting them
on a dynamic, minute to minute basis for optimum throughput. With
traditional systems, you painstakingly adjust the TNC parameters once
(static parameters) and hope that it will not be too inefficient. With
FlexNet, the parameters are watched and adjusted on a minute by minute basis
(dynamic parameter settings controlled by the software's A.I.) so that at
any given minute, your TNC is perfectly adjusted to the conditions it finds
with a connection.

End result? Significantly better throughput than any other connected mode
protocol available to hams.

You have to enter your callsign, your data rate and your TXDELAY... All
other parameters are controlled by the FlexNet A.I.. (Artificial
Intelligence) It's like having a little TNC expert hiding in your computer,
who constantly, expertly adjusts your TNC for you as you operate. This type
of software is referred to as an "Expert System", and is the only software
of this type that is wrtitten for hams. (That I am aware of.)

Over a good RF path, FlexNet will send up to seven 256 PACLEN packets at a
time. (Per key-up of the Xmitter) which gives it a data stream almost as
continuous as RadioMirror!

That's nice, but this is even better: When the link conditions deteriorate
(static, other traffic, etc. ) then FlexNet will "automagically" back off on
its radical TNC parameters until it no longer experiences retries, thereby
giving you the maximum possible throughput under ANY operating conditions,
good or bad - All the time!

When conditions improve again, FlexNet notices within a few minutes and will
again open up the TNC parms "like a hose" to give you the very best
throughput under whatever operating conditions the software encounters.

You can run IP over FlexNet of course, but the increased overhead will slow
you down a little. If you don't have a specific need for it, you will be
better off without it.

To find info about FlexNet, look under "Packet Software" in USPN's "Links"
page, and see the Flex32 tutorial in our "Turorial" section.

Good Luck! RadioMirror and FlexNet are your two best options for maximum
throughput at 9.6kb.

Let us know how it goes!

Charles Brabham, N5PVL
Director: USPacket.Net
http://www.uspacket.net

"Andy Knitt" wrote in message
...
Hello Everyone,

I'm very new to packet radio/digital communications and am trying to climb
up the learning curve too fast. It hurts :-) My question is: What
protocol/mode will give me the best data throughput using 9600 baud packet
on VHF or UHF?

Earlier I responded with information about RadioMirror, the multicast
protocol for terrestrial packet that offers truly outstanding
throughput... - But Andy may prefer a connected protocol. In that case,
FlexNet's AX25 stack will give him the best throughput, leaving traditional
AX25 and IP systems in the dust.

A standard TNC has close to 100 different parameter settings that influence
how well the TNC communicates with the computer over the serial link, and
how it performs on the air when hooked up to a radio. Even experts are
sometimes confused by some of the more esoteric link parameters, so many of
these are left at factory default values that are not what you could call
"optimum" but rather represent a compromise.

FlexNet takes full control of all of those link parameters, adjusting them
on a dynamic, minute to minute basis for optimum throughput. With
traditional systems, you painstakingly adjust the TNC parameters once
(static parameters) and hope that it will not be too inefficient. With
FlexNet, the parameters are watched and adjusted on a minute by minute basis
(dynamic parameter settings controlled by the software's A.I.) so that at
any given minute, your TNC is perfectly adjusted to the conditions it finds
with a connection.

End result? Significantly better throughput than any other connected mode
protocol available to hams.

You have to enter your callsign, your data rate and your TXDELAY... All
other parameters are controlled by the FlexNet A.I.. (Artificial
Intelligence) It's like having a little TNC expert hiding in your computer,
who constantly, expertly adjusts your TNC for you as you operate. This type
of software is referred to as an "Expert System", and is the only software
of this type that is wrtitten for hams. (That I am aware of.)

Over a good RF path, FlexNet will send up to seven 256 PACLEN packets at a
time. (Per key-up of the Xmitter) which gives it a data stream almost as
continuous as RadioMirror!

That's nice, but this is even better: When the link conditions deteriorate
(static, other traffic, etc. ) then FlexNet will "automagically" back off on
its radical TNC parameters until it no longer experiences retries, thereby
giving you the maximum possible throughput under ANY operating conditions,
good or bad - All the time!

When conditions improve again, FlexNet notices within a few minutes and will
again open up the TNC parms "like a hose" to give you the very best
throughput under whatever operating conditions the software encounters.

You can run IP over FlexNet of course, but the increased overhead will slow
you down a little. If you don't have a specific need for it, you will be
better off without it.

To find info about FlexNet, look under "Packet Software" in USPN's "Links"
page, and see the Flex32 tutorial in our "Turorial" section.

Good Luck! RadioMirror and FlexNet are your two best options for maximum
throughput at 9.6kb.

Let us know how it goes!

Charles Brabham, N5PVL
Director: USPacket.Net
http://www.uspacket.net

"Joseph Fenn" wrote in message
va.net...
Well for one simple thing you set your "MAXFRAMES" to 7.
Set PACLEN to 255. That wont change your baud rate but providing
signals are good it will give you the max thruput on msg traffic.
Joe/ABM6JF


Some experiments over an obstructed path on 70 cm,
9600 baud, suggest maxframe 16 - 32 and paclen of
60 -100 give the maximum throughput. Note that this
is an implementation of AX.25 that uses slow-start
and selective reject / out-of-order frame recovery.

Across a "very good" line of sight path, maxframe of
32 and paclen of 1024 did best.

These were point-to-point links, half duplex.
About 10 MB of data were used for the tests.

--

... Hank

Hank: http://horedson.home.att.net
W0RLI: http://w0rli.home.att.net