[SR-Users] Kamailio - RTPProxy - Asymmetric RTP

[Daniel Grotti]

Hi Girard,

looks like the Provider are sending RTP from port 5392 instead of 5394
as in SDP, rtpproxy send traffic to 5392 as well.


Daniel




On 10/31/2013 04:13 PM, Lucas Girard wrote:
> 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
> 
> 
> 
> 
> 
> 
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