Re: Question on select() and sockets

David Schwartz <davids@xxxxxxxxxxxxx> writes:
On Jun 10, 2:48 am, Rainer Weikusat <rweiku...@xxxxxxxxxxx> wrote:
POSIX/ SUS doesn't contain definitions of particular transport
protocols. UDP is defined as a thin layer above IP, just adding a
'datagram body' with a length field, support for checksumming that,
and source and destination ports so that different applications using
UDP on a single host can as easily be supported as for TCP. This means
that UDP has all the 'transport characteristics' of IP, meaning each
datagram travels indepedently and involved devices are supposed to
make a 'best effort' attempt to further delivery. Nothing is specified
regarding behaviour of the end system after a datagram was delivered
to it.

In other words, a UDP datagram can be dropped at any time.

And this is wrong. If a UDP datagram is lost in transport for some
reason, it is the responsibility of the application to cope with that.
That's all what the protocol definition (of IP, actually) says to
this.
.

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