[streaming] VLC Scalability

Marshall Eubanks tme at multicasttech.com
Thu Feb 5 11:47:18 CET 2009


On Feb 5, 2009, at 5:03 AM, Philip Frey1 wrote:

>
> Hello,
>
> we are running an experiment to evaluate the scalability of the VLC  
> in RTP mode.
> For some reason we find that the server does not scale beyond 330  
> clients no
> matter what bitrate our movie is (we are streaming Quicktime content).
>
> When streaming Full HD content (~9Mbps), the number of clients is  
> limited by the
> CPU power of the server. When using Standard Definition content  
> (~1Mbps and ~3Mbps),
> the CPU load increases up to about 330 connected client and then  
> dropps suddenly
> to almost 0 and the clients no longer receive any data.
>
> Do you have an explanation for this behavior? Is there a hard limit  
> on the number of
> clients that can connect to the VLC server using RTP?
>

It would be useful to specify the operating system and hardware that
these tests are being conducted on, and also the disk I/O speed. I  
find that
disk I/O speeds are the biggest limit in practice to scaling on (qtss)  
servers.

Also, are you sending 1 copy of the same stream to many clients, or  
different copies
of different streams to many clients ? This has a big effect on the  
disk I/O issue.

Regards
Marshall


> We were running the same experiments also on the Darwin Streaming  
> Server and
> found that DSS can do up to 400 clients (and even more) for small  
> bitrates.
> With regard to HD content, the DSS is also limited by the CPU on the  
> server.
>
> Many thanks for your advice,
>  Philip
>
> -- 
>   Philip Frey
>   IBM Zurich Research Laboratory
>   Saumerstrasse 4                                   |  Phone: +41 44  
> 724 8613
>   CH-8803 Rueschlikon/Switzerland  |  Email: phf at zurich.ibm.com_______________________________________________
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