[SR-Users] Kamailio - RTPProxy - Asymmetric RTP

[Lucas Girard]

Hi all,
I have an issue with a Kamailio and rtpProxy, when Asymmetric RTP is
used.  

I have the system running, lines registered in Kamailio are able to call
to several destinations, but I have a problem with one provider that use
Asymmetric RTP (others providers use Symmetric RTP and I dont have any
issues).

A -----> Kamailio & RTPProxy ----------> Trunk -------> Provider
(Asymmetric RTP) -------> B

A is calling B.
The problem is that line in kamailio A can listen to B, but B can not
listen what A says. 

I have captured the sip dialog and rtp traffic and I can see that:

Kamailio tells to provider that is using the port 52388 (media port in
SDP).
Providers tells Kamailio that is using the port 5394 (media port in
SDP).
RTP traffic from Providers to kamailio goes from port 5392 to 52388. 
RTP traffic from Kamailio to Provider goes from port 52388 to 5392.


I have not found an RFC regarding Asymmetric RTP. The question are,
 why RTP is sent from Kamailio (rtpproxy) to Provider to destination
port 5392? 
It should use 5394 as SDP indicate? 
or, port 5392 is learned when RTP traffic was received from 5392 to
52388?


# kamailio -V
version: kamailio 3.3.0 (i386/linux)
flags: STATS: Off, USE_IPV6, USE_TCP, USE_TLS, TLS_HOOKS, USE_RAW_SOCKS,
DISABLE_NAGLE, USE_MCAST, DNS_IP_HACK, SHM_MEM, SHM_MMAP, PKG_MALLOC,
F_MALLOC, USE_FUTEX, FAST_LOCK-ADAPTIVE_WAIT, USE_DNS_CACHE,
USE_DNS_FAILOVER, USE_NAPTR, USE_DST_BLACKLIST, HAVE_RESOLV_RES
ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144, MAX_LISTEN 16,
MAX_URI_SIZE 1024, BUF_SIZE 65535, DEFAULT PKG_SIZE 4MB
poll method support: poll, epoll_lt, epoll_et, sigio_rt, select.
id: unknown
compiled on 22:17:07 Jun 18 2012 with gcc 4.4.5

# rtpproxy -v
Basic version: 20040107
Extension 20050322: Support for multiple RTP streams and MOH
Extension 20060704: Support for extra parameter in the V command
Extension 20071116: Support for RTP re-packetization
Extension 20071218: Support for forking (copying) RTP stream
Extension 20080403: Support for RTP statistics querying
Extension 20081102: Support for setting codecs in the update/lookup
command
Extension 20081224: Support for session timeout notifications


I hope to be clear with this explanation.

Regards,

Lucas Girard




-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.sip-router.org/pipermail/sr-users/attachments/20131031/f54ed14d/attachment.html>