[Serusers] RTP being sent to wrong port

Jiri Kuthan jiri at iptel.org
Fri Sep 22 03:19:07 CEST 2006


The client should be then fixed or exchanged. It is not yet a BCP RFC or so,
but it should be soon. In the meantime it is just an informal but important
practice to build clients in a symmetric way. I'm actually aware of few
that are not build this way.

-jiri

At 18:12 20/09/2006, Andrey Kuprianov wrote:
>Just looked up the code to make sure... :) It's definitely assymetric!
>Thanks Vamsi!!!
>
>On 9/20/06, Vamsi Pottangi <vamsipottangi at gmail.com> wrote:
>>
>>Symmetric client uses the same port to send and receive messages.
>>
>>
>>On 9/20/06, Andrey Kuprianov <andrey.kouprianov at gmail.com > wrote:
>>> Forgive my ignorance. I know the term "symmetric client", but i dont
>>> really know what that means. Can u please explain or just give me some
>>> doc/rfc to read? :)
>>>
>>>    Andrey.
>>>
>>> On 9/20/06, Vamsi Pottangi < vamsipottangi at gmail.com> wrote:
>>> >
>>> > Is your application symmetric?
>>> >
>>> >
>>> > On 9/20/06, Andrey Kuprianov < andrey.kouprianov at gmail.com> wrote:
>>> > >
>>> >    Hi,
>>> >
>>> > Im facing this problem for a few days already. Hope someone might have
>>> > an idea or two. It's a long email too, btw.
>>> >
>>> > Im testing my app behind NAT's with SER-0.9.6 + mediaproxy + Asterisk
>>> > (conf server). While X-Lite works *fine* and I get 2 way audio always,
>>> > my app seems to have some kind of weird bug and I end up with 1 way
>>> > audio stream.
>>> >
>>> > Here's the thing. Application starts receiver and transmitter on
>>> > completely different ports. Here's SDP for remote and local machines
>>> > (public IP's been x'ed by myself, of course):
>>> >
>>> > This one's sent in INVITE message to SER ==>
>>> > 69563 DEBUG media.MediaManager - Local SDP: (this one's from local
>>machine)
>>> > v=0
>>> > o=xps 1158739216750 1158739216757 IN IP4 192.168.1.3
>>> > s=MC
>>> > c=IN IP4 192.168.1.3
>>> > t=0 0
>>> > m=audio 25000 RTP/AVP 0 8
>>> > a=rtpmap:0 PCMU/8000
>>> > a=rtpmap:8 PCMA/8000
>>> > a=sendrecv
>>> >
>>> > This one's sent with 200 OK from SER ==>
>>> > 69563 DEBUG media.MediaManager - Remote SDP:
>>> > v=0
>>> > o=root 2500 2500 IN IP4 203.159.x.x
>>> > s=session
>>> > c=IN IP4 203.159.x.x
>>> > t=0 0
>>> > m=audio 30004 RTP/AVP 0 8
>>> > a=rtpmap:0 PCMU/8000
>>> > a=rtpmap:8 PCMA/8000
>>> > a=silenceSupp:off - - - -
>>> >
>>> > The further log shows that transmitters and receivers have started on
>>> > the proper IP/port ==>
>>> >
>>> > 69594 DEBUG media.AVReceiver -  Start listening for RTP @ addr:
>>> > 192.168.1.3 port: 25000 ttl: 1
>>> > 69657 DEBUG media.AVTransmitter - Created transmitter for:
>>> > [203.159.x.x] at ports: [30004] encoded as: [[ULAW/rtp, alaw]]
>>> > 69657 DEBUG media.MediaManager - Starting transmission
>>> > 69672 DEBUG media.AVTransmitter - Track 0 is set to transmit as:
>>> > ULAW/rtp, 8000.0 Hz, 8-bit, Mono, FrameSize=8 bits
>>> > 69860 INFO media.AVTransmitter - Binded to port 30004
>>> > 69875 DEBUG media.AVTransmitter - Started transmitting track 0 encoded
>>> > as ULAW/rtp @ [203.159.x.x]:30004
>>> >
>>> > Nevertheless, the Ethereal capture shows that mediaproxy sends the
>>> > stream NOT to port 25000 (local port), but to port 30004 (remote
>>> > port)!! Why? This is not the case with X-Lite, however. Xlite captures
>>> > show that streams are sent to proper ports always. Btw, Im attaching
>>> > SIP+RTP Ethereal captures with this mail. Please, take a look.
>>> >
>>> > I also want to mention, that this doesnt happen with my app. for all
>>> > the NATed nets. In some nets it works fine, but not in this one. Just
>>> > weird.
>>> >
>>> > Please, let me know if anyone has ideas or hints regarding this nonsence
>>:)
>>> >
>>> >    Bests,
>>> >
>>> >     Andrey.
>>> >
>>> >
>>> > _______________________________________________
>>> > Serusers mailing list
>>> > Serusers at lists.iptel.org
>>> > http://lists.iptel.org/mailman/listinfo/serusers
>>> >
>>> >
>>> >
>>> >
>>> >
>>> _______________________________________________
>>> Serusers mailing list
>>> Serusers at lists.iptel.org
>>> http://lists.iptel.org/mailman/listinfo/serusers
>>>
>>
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--
Jiri Kuthan            http://iptel.org/~jiri/ 




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