[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: Solving the need for ISA or USB slots and SerialPorts

Hash: SHA1

On Jul 2 2003 14:59 -0400, Don Woodward wrote:

> UDP is not guaranteed for delivery whereas IP is - do you really want your

I know this is a little bit off-topic but do feel that this statement needs
correction anyway. IP is not guaranteed for delivery.

The two most commonly used protocols on the Internet for ordinary
applications today are TCP and UDP, which use IP (IPv4 or IPv6) as their
"next lower layer", that is, lower meaning closer to the physical medium (RF,
electrical cabling, light, whatever).

That is why IPv6 doesn't require TCP and UDP to be redesigned - only the IP
transportation protocol needed reworking. (Ah, the wonders of the OSI model.)
Likewise, we could just as well run HTTP over a piece of string and two empty
cans - HTTP only needs to be able to expect that a packet injected in one end
gets delivered at the other end, and doesn't care about the technicalities on
how that is accomplished. It would work exactly as well over IPX (which is
from the Novell world and has nothing to do with IP, by the way).

So, if you want to know that the package gets delivered without sending an
acknowledgement yourself, use TCP. If you don't really care (streaming audio
is one application, DNS name resolution is another) then UDP is often better
due to its lower latency. (One packet instead of three plus one plus three.)

Michael Kjörling

- -- 
Michael Kjörling :: michael@kjorling.com :: SMØYBY JO89  ^..^
PGP: 3723 9372 c245 d6a8 18a6  36ac 758f 8749 bde9 ada6   \/
Also 95f1 074d 336d f8f0 f297  6a5b 2aa3 7bfd 8a70 e33e (old)
Version: GnuPG v1.2.1 (GNU/Linux)
Comment: Made with pgp4pine 1.76


Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org