[Kamailio-Users] NAThelper and multipart SDP

[Klaus Darilion]

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

I think you can start multiple rtpproxy processes and do load balancing 
between them.

regards
klaus

> - 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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