[Nel] TCP vs. UDP

Fri, 6 Jul 2001 19:41:50 +1000

You *must* replace your transport mechanism with UDP :)
+
+TCP provides (nah, ensures) reliable delivery of data, but it can spend a
+long time transmitting (especially on clogged up links). Between packet
+errors and backoffs due to packet drops it can easily take 2seconds plus to
+get data down the "tcp pipe". And seeing its a pipe, everything behind it is
+"backed" up. So, time critical data can't just jump past useless data (like
+MOTD's,etc).
+
+With UDP on the otherhand, you lose the reliable data, but you get your
+timeliness. Because of the datagram nature of transmission, you can also
+implement independant "streams", with reliablity on some streams (via extra
+software layers) and timeliness on others (auto drop of old data for eg).
+
+Btw, you cannot "design your own layer", because you need to use the
+existing internet to send your data (which will only accept UDP and TCP).
+However, they probably did add to UDP, by adding an extra software layer to
+provide "reliable udp" (its almost trivial to do).
+
+Any, UDP is the only option that is sensible for anything that has time
+critical performance or for things with mutliple "data channels".
+
+BTW, I do stuff like this for a living (I am a network researched for
+www.dsto.defence.gov.au), with a fair bit of work in the voice arena, so I
+have some experience backing me up here :)
+
+
+----- Original Message -----
+From: "Vianney Lecroart" <lecroart@nevrax.com>
+To: <nel@nevrax.org>
+Sent: Friday, July 06, 2001 12:36 AM
+Subject: [Nel] TCP vs. UDP
+
+
+> Hi everybody!
+>
+> Let's talk a little bit about this great subject: TCP vs. UDP
+>
+> Thanks to Valerio Santinelli and Olivier Lejade, there's some cool
+> discussion about this subject on the web and I would like to have your
+> thought and discuss about this.
+>
+> On Anarchy Online game, they only use TCP protocol between client and
+server
+> (other commercial online game use UDP) and it seems that it causes lot of
+> problem like horrible ping or connection lost:
+> http://aoforums.funcom.com/showthread.php?threadid=26297
+>
+> There's also a mail on the MUD-Dev mailing list talking about these
+problems
+> here:
+> https://www.kanga.nu/archives/MUD-Dev-L/2001Q3/msg00009.php
+>
+> As you perhaps know, we only use TCP/IP (for server-server communication,
+> but also for the client-server connection) and we currently think more and
+> more about replacing the TCP client-server connection with a UDP one.
+>
+> In a first step, we would like to know your opinion about this choice. And
+> in a next step, we'll do some test about ping/packet lost and so on to
+> compare TCP and UDP, and we'll need your help to do that.
+>
+> Vianney Lecroart
+> ---
+> lead network programmer / nevrax.com
+> icq#: 6870415
+> homepage: http://ace.planet-d.net
+> www.geekcode.com: GCS/E d- s+++: a-- C+++$ UL++ P- L+++>+$ E+>- W++ N+ o?
+K-
+> w++$ O- M- V- PS- PE? Y PGP t 5? X+ R- tv++ b- DI D+ G e++ h+ r-- y?
+>
+>
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+>
+
+
+