Linux multicast is slower than Windows multicast ?

Linux multicast is slower than Windows multicast ?

Post by Manu » Thu, 22 May 2003 23:25:48



I'm developing 2 applications :

1- A program that runs under linux (mandrake 9.0) and sends multicast
packets (code is very simple, similar to this:
http://www.linuxsocket.org/books/Sockets/programs/part4/chap17/mcast_...)

2- A program under Windows2000 that receives multicast packets (sent
by linux program)

I noticed that linux transmitter is very slow. I tried to transmit
same packets using Windows application and I noticed that win2000 is
faster (10 times) than Linux. I tried different packet sizes:
transmission under linux is slower than Windows only for big packets
(>20KB).
Have somebody noticed same behaviour ?
Is there some configuration (kernel or user) that can improve Linux
performance ?

Thanks,

Manuel

 
 
 

Linux multicast is slower than Windows multicast ?

Post by Kevin Easto » Fri, 23 May 2003 23:59:02



> I'm developing 2 applications :

> 1- A program that runs under linux (mandrake 9.0) and sends multicast
> packets (code is very simple, similar to this:
> http://www.linuxsocket.org/books/Sockets/programs/part4/chap17/mcast_...)

> 2- A program under Windows2000 that receives multicast packets (sent
> by linux program)

> I noticed that linux transmitter is very slow. I tried to transmit
> same packets using Windows application and I noticed that win2000 is
> faster (10 times) than Linux. I tried different packet sizes:
> transmission under linux is slower than Windows only for big packets
> (>20KB).
> Have somebody noticed same behaviour ?

Nope...

Quote:> Is there some configuration (kernel or user) that can improve Linux
> performance ?

Such packets are almost certainly being fragmented (if you're using an
ethernet, the MTU is 1500).  Perhaps it is the fragment reassembly time
at the other end that is being slow?  Are you seeing lots of collisions?
Are the network cards the same?  Do you have a duplex mismatch on that
interface?

        - Kevin.

 
 
 

1. Multicast X windows under Linux

Hi!

I am looking for information on how to broadcast
a single X window to many clients over a network.

Background:
I am trying to find out how to build an efficient
Linux based computer class with the ability for
pupils to ask for help interactively (trivial) and
for the teacher to display his active window to all
pupils at the same time (no information found so far).

Any pointers to information on how this could be done
would be very appreciated.

This is a hobby project and so far I have the following
working sorftware:

- A query program allows a pupil to pop up a window on the
  teacher's screen. The teacher can accept or reject
  the query. If the query is accepted the pupil can show
  a window selectable by the pupil to the teacher.
  (Written in Tcl/tk)

- A very light weight chat client/server with different
  filtering options and the ability to define chat groups.
  It is for example possible to filter out messages belonging
  only to me and the teacher, my own group or all chatters.
  The idea has been to build a system requiring much less
  resources than for example Netscape + a chat server based
  on CGI scripts (client machines are 486 DX266).
  (Written in c using Xforms for the GUI)

Planned further functionality:

- Broadcast a window to the whole class.
  (Looking for necessary technical info)

- Language studio allowing broadcast of teachers example
  speech data. Allowing the teacher to listen to any
  pupil doing local training. Possibly training
  pronounciation using for example waveform display.
  (No research is yet done on this application)

Ideas etc. regarding any of the topics above are welcome.
The idea is to try to build a FREE Linux based classroom
package allowing an extended life to a few years old
computer classes where upgrading to Win98 + suitable
Office programs would be unnecessary expensive. The idea
is to use Linux in combination with Applixware or
Staroffice because a site licence is affordable even under a
tight budget. I hope to be able to put out some information
regarding the project above on my home page in the near
future including example programs.

Regards
Lars Silen (FINLAND)



http://www.kolumbus.fi/larsil

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