[SDL] UDP packet managing vis sdlnet

Oisin Mulvihill Oisin.Mulvihill at trintech.com
Wed Aug 15 02:07:01 PDT 2001


why don't you just use stream sockets? Its simple
and straight forward to use. You could get your
project working and then go back to UDP later if
you really need it. 


-----Original Message-----
From: david ackley jones [mailto:davej at midway.uchicago.edu]
Sent: Tuesday, August 14, 2001 11:50 PM
To: sdl at libsdl.org
Subject: Re: [SDL] UDP packet managing vis sdlnet

I actually understand some of the theory behind UDP, but I'm kinda stuck
on the implementation side of it.  Actually, I can't say that I really
understand what 'channels' are in the SDLNet library.  I would've guessed
you'd just stuff em in a socket and not worry about it anymore.  The
channel part has me baffled.

Not broadcast, but the server sends out a beacon to its clients via TCP.  

Maybe if I explained what the end project is:  I'm modifying someone's
code that reads in keyboard events from a windows box and sends them via
TCP to its connected clients which are running Linux.  The linux clients
read the incoming data, parse them, and has X run them.  You'd up having
keyboard control of a bunch linux boxes with a windows machine.

I'm currently adding the mouse support.  Mouse movement doesn't have a
high priority and there's a lot of it.  Therefore, UDP packets make sense
for sending out that data.  Before I go there, I wanted to get comfortable
with SDLnet's library.  Which brings me to my current situation.

Any more comments are welcome.  thx

On Tue, 14 Aug 2001, =?ISO-8859-1?Q?Mattias Engdeg=E5rd?= wrote:

> >I only briefly looked at the code, but I highly doubt you can send UDP
> >TCP packets with the same socket or on the same port, at the same time or
> >while TCP is connected.
> UDP and TCP have separate port spaces so this is not a problem
> >All in the name of effecieny.. thats why UDP is
> >generally used where packet loss is expected, such as streaming
> >applications.
> It is correct that UDP packets may be lost or reordered/duplicated but
> not that they are necessarily more efficient (on some data links TCP
> has both higher bandwidth and lower latency). However since you must
> implement your own flow control with UDP you can tailor it better to
> your needs (and make it more tolerant to dropped packets etc)
> >> Currently, the
> >> server side waits for clients to connect and then periodically
> >> TCP and UDP packets to all of the connect clients.
> you can't broadcast TCP packets but I assume you didn't use it in a
> technical sense.
> There can very well be nasty dragons hiding inside SDL_net -- I haven't
> ventured into it very far myself. I would prefer to debug it using
> dynamite :-)
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