[Freeswitch-users] SRTP scaling issues

Richard Chan richard at treeboxsolutions.com
Tue Oct 31 18:20:10 UTC 2017

Just an idea: to isolate you use something else just to offload SRTP: e.g
use rtpengine for SRTP/RTP bridging. This could show whether
FreeSWITCH+SRTP is really to blame. You could even run rtpengine on the
same box as FreeSWITCH since the CPU load looks manageable.

Media path would look like:
webrtc --[SRTP] -- (rtpengine+kamailio-to-rewrite-SDP) --[ RTP] --

On Tue, Oct 31, 2017 at 4:37 AM, Matthew Meek <mmeek at livexchange.com> wrote:

> We have been using Freeswitch as our SBC and core switch for many years
> without issues. Recently we added public facing softphones using an
> additional server running Kamailio as TLS and webrtc bridge with FS
> handling media back to our core FS farm.  We run a mix of webrtc and Zoiper
> softphones. All running SIPS (tls) but webrtc is SRTP (PCMU) and Zoiper is
> We have been ramping up the webrtc traffic and at some magic point at busy
> times (~150 concurrent calls) the RTT and Packet loss for the webrtc calls
> goes crazy (as measured in the browser via RTCP and captured back on our
> logging servers). RTT jumps from 100ms to 2-3 seconds for most or all
> webrtc users and packet loss jumps from nothing to troubling on the Sending
> side back to FS only. Packets received are not an issue on webrtc side…
> webrtc can hear end caller, but end caller cannot hear webrtc well.  Non
> webrtc traffic (Zoiper) have no reported impact. Server CPU (dual socket 6
> core) looks great (no core over 20%) according to nmon… packets per second
> within reason (10Gb NICs).
> I am assuming the SRTP has some hidden scaling issue since this is the
> only difference between the two types of softphones. Has anyone seen this
> or have a workaround?
> I am at a loss. I assume if it is encryption overhead the CPU would be
> saturated and it is not. Why a single direction of SRTP traffic is impacted
> has me up late at night.
> A side note… does anyone know of a SIPP replacement that does SRTP so I
> can test load against this to isolate?
> Thanks,
> Matthew Meek
> _________________________________________________________________________
> Professional FreeSWITCH Consulting Services:
> consulting at freeswitch.org
> http://www.freeswitchsolutions.com
> Official FreeSWITCH Sites
> http://www.freeswitch.org
> http://confluence.freeswitch.org
> http://www.cluecon.com
> FreeSWITCH-users mailing list
> FreeSWITCH-users at lists.freeswitch.org
> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
> http://www.freeswitch.org

Richard Chan
Chief Architect

TreeBox Solutions Pte Ltd
1 Commonwealth Lane #03-01
Singapore 149544
Tel: 6570 3725

Co.Reg.No. 201100585R
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freeswitch.org/pipermail/freeswitch-users/attachments/20171101/6031ad59/attachment.html>

More information about the FreeSWITCH-users mailing list