[Kamailio-Users] NAThelper and multipart SDP

[Daniel-Constantin Mierla]

Hello,

On 06/24/2009 10:09 PM, Andreas Granig wrote:
> Hi,
>
>> Someone does need to do a study to see if kernel vs. userspace 
>> forwarding really makes that much of a difference, though.  I suspect 
>> that although it does make a difference, it is not nearly as much of 
>> a difference as is commonly thought.
>
> We did a benchmark (only cpu usage for now) comparing the standard 
> rtpproxy with mediaproxy-ng, a proprietary implementation of Sipwise 
> (implemented as iptables module based on the mediaproxy dispatcher 
> protocol). The results should be pretty equal for mediaproxy2 and 
> iptrtpproxy as well, although I don't know anything about their design.
>
> http://pub.sipwise.com/OpenSER.rtpproxy.benchmark.2009.06.24.pdf
>
> The machine is a Dual-CPU Intel(R) Xeon(TM) CPU 2.80GHz with 2GB of 
> RAM. Test-Setup is done with sipp (rtp is sent via pre-recorded pcap 
> and echoed via "-rtp-echo" option on UAS).
>
> Some observations we found:
>
> - rtpproxy seems to not take advantage of SMP
it is well known, but you can run one or two instances per core and load 
balance from the nathelper module. I usually start 2 per cpu core.

Cheers,
Daniel


>
> - jitter is reduced in mediaproxy-ng compared to rtpproxy because 
> socket polling is eliminated in kernel
> - delay is reduced in kernel-space due to elimination of context 
> switching
> - the peaks in mediaproxy-ng are a result of the mediaproxy-ng design 
> (relaying is done in user-space until all ip/port information is 
> available by receiving rtp packets from both sides, besides some other 
> processing like packet inspection etc. [although cpu usage can be 
> lowered even more by further optimizing the userspace part])
>
> Andreas
>
>
>
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-- 
Daniel-Constantin Mierla
http://www.asipto.com/