Re: UDP network problem

Richard B. Johnson (root@analogic.com)
Tue, 19 Aug 1997 08:41:33 -0400 (EDT)


On Tue, 19 Aug 1997, Matei Conovici wrote:

> On Mon, 18 Aug 1997, Richard B. Johnson wrote:
>
> > room or the header?? You can't fragment UDP so, as I understand it, you
> > should never be able to send more than 1480 bytes on UDP. Or am I missing
> > something?? Have the Specs changed? Can you now blast through anything??
>
> What do you mean ? Fragmentation is done at the IP layer ... so why does
> this have anything to do with UDP ? Did I miss something here ?

Well when I started in "Networking" about a thousand years ago when we
used puffs of smoke for communication, a "Datagram" was a single packet
of information which was not guaranteed to go anywhere nor was it
guaranteed to arrive in the correct order. Datagrams came in two types
inband, and out-of-band. You would send out-of-band datagrams for
signaling. Data would go in-band. UDP (Unix Datagram Protocol) are
(were) datagrams with an IP Header. If the IP "layer" now allows one
to fragment, i.e., use datagrams that no longer consist of a single
packet, then the whole reason for using datagrams has disappeared.

Cheers,
DJ
Richard B. Johnson
Analogic Corporation
Penguin : Linux version 2.1.51 on an i586 machine (66.15 BogoMips).
Warning : It's hard to stay on the trailing edge of technology.
Linux : Engineering tool
Windows : Typewriter