Hello Julian
On Thu, 21 Jan 1999, Julian [ISO-8859-1] Mu�oz[ISO-8859-1] Dom�nguez wrote:
>
> I have been looking the ax25 source code, and didn't find nothing wrong.
Thats pleasing.
> I think that this was done at the beginning, because timers were not
> implemented, but now there is no reason for doing poll in the last frame of the
> ax25 tx window; most of the implementation do not, and if that's causing
> problems the best is remove it (imho).
The reasoning for attaching a poll to the last I frame in a window was
something me and John G8BPQ worked out (his code does it BTW). The idea
behind it was to improve performance, normally the receiving station would
wait T2 from last hearing a frame from the remote end, before replying
with an RR. The logic we used goes a little further, if we have sent a
full window and are therefore not going to send any more to him (except
retries), why not remove T2 from the equation by asking for an immediate
reply from the remote station.
I don't actually see how it could break anything to be honest.
The original textual description of AX.25 was very hazy on that point and
so we felt able to add a little :-) It is such issues that make me a
strong believer in SDL diagrams. If anyone wants to read a bad textual
description of a protocol, try the LAPB/X.25 specification from the CCITT.
I managed to get a university dissertation out of that particular mess.
> --
> Saludos de Juli�n
> -.-
Jonathan HB9/G4KLX in Zurich
