http://www.b2bua.org/wiki/RTPproxy/FAQ

RTPproxy Frequentry Asked Questions (FAQ)

General ¶

I have found a bug in the software, what should I do?

Send problem report to  devel@rtpproxy.org. Include as many details as you can into your problem report, such as version of RTPproxy, version of operating system, your SIP network topology and so on.

What codecs the RTPproxy supports? Do I need to purchase license to proxy royalty based codecs?

In the RTP forwarding mode the RTPproxy is fully codec-agnostic, which means that it supports any voice/video codecs, including such royalty-based codecs as G.729 and G.723.1. It doesn't perform any encoding, decoding or transcoding, so that there is no need to posess a license.

How can I extract audio from the recorded .pcap files?

It is possible to extract audio using  rtpbreak, sox and lame (for mp3).

First, the conversion of each channel in the raw:

rtpbreak -W -r longfilename_of_rtpproxy_record.a.rtp
rtpbreak -W -r longfilename_of_rtpproxy_record.o.rtp

Then mix in the format wavpcm stereo:

sox --combine merge -r 8k -A rtp.0.0.raw -r 8k -A rtp.1.0.raw -t wavpcm -s out.wav

and, finally, converting to mp3:

lame out.wav out.mp3

Performance

How many simultaneous call (sessions) could RTPproxy handle?

It is impossible to give exact answer as it depends on many factors, including session codec, RTP payload size, hardware, operating system and so on. However, when running on a modern x86 server it should be able to handle at least 1,500-2,000 simultaneous sessions, provided that there is sufficient network bandwith available.

Will RTPproxy take advantage of the modern SMP (multi-core) hardware?

No, the RTPproxy is single-threaded software, so that it won't be able to benefit from running on more than one CPU/core. However, it's easy to configure several RTPproxy istances to run on the same machine in parallel. To maximize performance and minimize RTP handling delay number of instances should match total number of available cores.

All packages that work with RTPproxy (SER, OpenSER, Sippy B2BUA) can use several RTPproxy in round-robin fashion, effectively distributing the load among them. It is important to remember to run all instances on non-overlapping UDP port ranges, so that there is no racing conditions between them to allocate UDP ports for incoming/outgoing sessions. The following example shows how to run 4 proxies to get best performance from 4 core system:

rtpproxy -l X.Y.Z.W -L 8192 -p /var/run/rtpproxy.pid -s /var/run/rtpproxy.sock -m 25000 -M 34999
rtpproxy -l X.Y.Z.W -L 8192 -p /var/run/rtpproxy1.pid -s /var/run/rtpproxy1.sock -m 35000 -M 44999
rtpproxy -l X.Y.Z.W -L 8192 -p /var/run/rtpproxy2.pid -s /var/run/rtpproxy2.sock -m 45000 -M 54999
rtpproxy -l X.Y.Z.W -L 8192 -p /var/run/rtpproxy3.pid -s /var/run/rtpproxy3.sock -m 55000 -M 64999

The signalling software that uses RTPproxy should be configured to use all 4 sockets (/var/run/rtpproxy.sock, /var/run/rtpproxy1.sock, /var/run/rtpproxy2.sock and /var/run/rtpproxy3.sock) to contact RTPproxy in this case.