On Fri, 8 Jan 1999, Thomas Sailer wrote:
> Riley Williams wrote:
>
> > Partly out of curiosity, and partly in connection with a project I
> > might be working on shortly, but can anybody advise whether the
> > current (2.2.0-preX) implementation of AX.25 implements either of the
> > SABME or SREJ frame types, and if so, whether there's any limitations
> > thereon?
>
> You're referring to AX25 V2.2?
He's referring to the extended AX.25 specification published by Rob PE1CHL
many years ago.
> SABME/SREJ is an attempt to implement selective repeat
> (instead of go back N). We (in central europe) already
> use a selective repeat scheme called "frame collector"
> for almost 10 years now. It uses existing protocol elements
> (RR P/F), is backward compatible, and does not incur much
> complexity.
I am sure the frame collector is wonderful but since nobody seems to send
these specs outside of Germany, don't blame the Americans for not
following, or taking any notice of it. I've never seen the spec for the
frame collector, I would be interested to see it though.
> The authors were SDL guys. I've already been bitten by
> SDL enthusiasts basing design decisions on SDL's features
> and thereby killing performance.
That was uncalled for. I used SDL diagrams for all of the protocols in the
kernel and I found it to be a huge advantage. You can say the same thing
about structured programming versus goto's, I'd still go with structured
programming any day.
> The way TAPR did the design process (essentially secretly,
> no one of the major AX.25 implementors, such as
> Nordlink or Flexnet) new anything about it or was even
> asked what they think of it.
Excuse me but in the "real world" neither of these two bodies are that
important. Inside central Europe they are, but outside they are small bear
to say the least. Nordlink are known outside of the German speaking world
for TheNet and nothing else, and that is going out of use. FlexNet has
greater penetration, but isn't that big.
> If you want a public standard followed by all major
> implementors, make the standard setting process open!!
>
> Tom
Can we do dinner again sometime Tom ?
Jonathan HB9/G4KLX in Zurich
