In article <_MWdncduPKGgXxXZnZ2dnUVZ_u2dnZ2d@comcast.com>,
News 2 Me <em2swen@comcast.net> wrote:

> new guy wrote:
> > <ankitjain.bvcoe@gmail.com> wrote in message
> > news:1149664377.664911.123520@g10g2000cwb.googlegr oups.com...
> >> Hi all ,
> >> I am new to this group .
> >> A basic question.I want to know what is a difference b/w TCP and UDP
> >> packet i.e how will u know that the data which u are receiving is
> >> travelling via a UDP/TCP packet without using any sniffer.
> >>
> >> ankit
> >>
> >
> > As you know, TCP uses 3-way handshake and it's connection oriented; TCP
> > gives guarenteed delivery, flow control and windowing. That's why TCP
> > packets use sequence numbers, acknowledge numbers, etc.; UDP packets don't
> > use sequence numbers. UDP is connectionless, which means best effort
> > delievery. Some of TCP protocols are POP3, SMTP, FTP, HTTP etc. whereas
> > some
> > of UDP protocols are TFTP, DHCP, SNMP etc.
> >
> > new guy
> >
> >
>
> UDP is definitely not best effort delivery. That would be TCP. UDP is
> minimal effort delivery. With UDP the packet is sent once and if it
> doesn't make, UDP couldn't care less.

That's not how the term "best effort" is normally defined. IP and UDP
provide best-effort delivery, while TCP provides guaranteed delivery.

See <http://www.linktionary.com/b/best_effort.html> for a good
description of these terms.

--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
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