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TCP-group 1991


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MAC sublayer protocol for TCP/IP



While we have obvious problems with the current norm, I see several
reasons why a token-based system isn't the fix for typical ham
operation.  BTW we had this discussion a year or two ago and maybe more
than once...

Token passing requires fast t/r turnaround, or each passing station will
add lots of delay.  With TxD's in the 300 ms. range,  it's pretty
pathetic with most ham sets.  Purpose-build radios would fix this but
most hams have voice radios. (Mine has real relays.)

Token passing has problems adding and subtracting stations.  There's
some reconfiguration delay whenever that occurs.  Hams drop in and out
all the time on access channels -- certainly I do.  That overhead alone
would be very bad.

And tokens mean that everybody "on channel" has to transmit regularly,
whether or not they have anything to send.  Given the turnaround times
and the nature of ham operation, this is a minus -- it's like automated
net operation without a net control, but worse.

Exisiting single-freq. access channels are indeed cruddy due to their
basically Aloha nature.  But if we used simple repeaters (even baseband
regenerators, like audio-style repeaters), we'd have true CSMA and no
HTS.  Then the existing p-persistent pseudo-CSMA would work.  Without
that, we just have to shoot anybody whose persistence is too high or
who doesn't back off. In other words, any of those typical TNC/AX.25
type users with window=5, etc....
   fred k1io





Document URL : http://www.a00.de/tcpgroup/1991/msg00052.php
Ralf D. Kloth, Ludwigsburg, DE (QRQ.software). < hostmaster at a00.de > [don't send spam]
Created 2004-12-21. Last modified 2004-12-21. Your visit 2020-10-27 15:04.03. Page created in 0.0488 sec.
 
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