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TCP-group 1995


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MACA, DUAL, FEC, etc.



All these ideas and proposals, but they're aren't all rolled into one
package or box.

Let's see:

there's MACA: Multiple Access with Collision Avoidance. Not
implemented as far as I know.

DUAL which is a replacement for AX.25 UI frames - uses VJ header
compression to save bandwidth.  Based on CSMA but could be used with
MACA. Coded for FreeBSD.

Error correction: Phil Karn posted his code for Viterbi and Fano
decoders. There's also GPL'ed code for Reed Solomon error correction.
(C code). So far not (?) specified in MACA or DUAL.

This would all seem like a very good basis for new amateur radio
software.

Then there is the TNC-The Next Generation group/mailing list (currently
bogged down in the 'it has to run on a 1200bps TNC and Commodore 64! vs
T1 speed and above, lead-follow-or-getouttatheway' debate. The original
purpose of which was to design new firmware for existing TNCs, while
planning for The Next Generation TNCs/hardware/modems.  There are also
various people tinkering on new modems etc (the TAPR HF sig for HF modems,
various 56k, 256kbps  and above modems)

The problem is how to bring all of this together. Any ideas?

Some thoughts:

- I've tested the error correcting code and it isn't fast enough even
  for 56kbps let alone higher, and if you have a multiple ports CPU
  loading gets worse. This sort of thing wwill have to go in the modem
  or TNC for high speeds, but can stay on the host CPU for low speeds.

- I like the AX.25 amateur radio support that you can compile into the
  Linux kernel, but other people use NOS or BSD. None of these kernel
  implementations can be mixed with the other without porting all over
  the place. What to do?

- Since everyone has TCP/IP (Apple, DOS, Windows, NT, OS/2, Unix) what
  could be done to make interfacing to Amateur radio TNCs or modems
  easier? The choice seems to be cobble together a NOS (or even Linux)
  box on an old 386SX, or put it in the TNC, making the TNC a lot like
  a Cisco router/terminalserver.

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Created 2005-01-02. Last modified 2005-01-02. Your visit 2020-10-29 16:10.41. Page created in 0.0589 sec.
 
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