Re: UDP bugs

Richard Gooch (rgooch@atnf.csiro.au)
Sun, 13 Dec 1998 20:18:58 +1100

David S. Miller writes:
> Date: Sun, 13 Dec 1998 13:50:25 +1100
> From: Richard Gooch <rgooch@atnf.csiro.au>
>
> >From this it appears Linux 2.1.x has an output limit of 65507
> >bytes and an input limit of 65476 bytes. Further, Linux 2.0.36 has an
> output limit of 65507 bytes (same as 2.1.x) and an input limit of
> 51792 bytes.
>
> Are you considering the size of IP and UDP headers? Those must be
> factored in.

I was under the impression that the payload capacity was 65535
bytes. And if it were true that the headers steal capacity, then why
can Solaris 2.5.1 send a full 65535 byte packet?

> Packets which exceed the maximum size go to the big bit bucket in
> the sky. RIP. This is a problem for programmes which "know" that
> they can send 65535 byte packets over UDP.
>
> Programs pushing such large UDP frames over ethernet don't "know" very
> much IMHO....

Full duplex switched EtherNet and IP over ATM (CLIP). Works fine, as
long as you don't transmit at a greater rate than the link can handle
(which is easy enough to arrange). Much better than TCP for this
application, as the occasional lost packet doesn't matter.

Regards,

Richard....

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/