[Spread-users] Tuning spread's performance for multicast

Jonathan Stanton jonathan at cnds.jhu.edu
Fri Apr 4 17:40:04 EST 2003

I can provide a 5 cent comparison...

I don't know MCL/fcast directly, but I took a quick look at the webpages
and I know of the researchers. 

Spread and MCL are trying to provide a different type of service, MCL is
providing reliable multicast of files and multimedia streams to a large
number of receivers. So it is a 1-many transfer and "file reliability"
is the main goal. Spread provides a "group messaging service" which is
more general (in that it supports many-many communication, and stronger
semantics like SAFE and AGREED), and is 'message' oriented (like a
datagram protocol) rather then 'stream' oriented like TCP. Spread can be
used to multicast files, as it provides a reliable datagram multicast
service, but since that isn't it's sole purpose it may not be as
optimized for that specific service.

There are a number of other differences in technical detail, but most of
them are a consequence of the difference in high-level goals.


On Fri, Apr 04, 2003 at 01:46:46PM -0800, Dave Viner wrote:
> I have a similar interest in using multicast to deliver files.  Have you
> looked at fcast?
> http://www.inrialpes.fr/planete/people/roca/mcl/man/fcast.man.1.html
> Its not based on Spread, but on MCL (MultiCast Library) which in turn is
> uses the ALC/LCT protocol
> http://www.inrialpes.fr/planete/people/roca/mcl/mcl_docs.html
> Can anyone more knowledgable than I highlight the differences between Spread
> and MCL?
> thanks
> dave
> -----Original Message-----
> From: spread-users-admin at lists.spread.org
> [mailto:spread-users-admin at lists.spread.org]On Behalf Of Guy Argo
> Sent: Friday, April 04, 2003 12:38 PM
> To: 'spread-users at lists.spread.org'
> Subject: [Spread-users] Tuning spread's performance for multicast
> I'm using Spread (under python) for a file delivery system.
> Basically I want to deliver several large files to multiple destinations
> simultaneously preferably multicasting them to minimize
> network usage. I attached my crude little python test bed.
> I got it to work and tested it on two machines on the same
> subnet and the performance was underwhelming.
> I achieved sustained throughput of 40KB/s for data sent using
> multicast with RELIABLE_MESS and FIFO_MESS protocols.
> The machines both have 100 Mb cards.
> FTP achieved 600 KB/s.
> Do you have any recommendations about how to tune
> Spread to increase the performance?
> I couldn't find anything in the doc. :(
> ---
> Guy Argo <gargo at looksmart.net> ph +1 415 348 7683
> Director, Production Engineering
> LookSmart Ltd., 625 2nd St., SF CA 94107
>  <<pushpull.py>>
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Jonathan R. Stanton         jonathan at cs.jhu.edu
Dept. of Computer Science   
Johns Hopkins University    

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