>> In my configuration there is no NAT whatsoever. Is there a way to disable NAT traversal completely, thereby working around this issue for the time being?

I should also add sipX being behind a firewall.


On 09/26/2012 12:15 AM, Jeff Pyle wrote:
Joegen,

Yes, exactly.  INVITE with no SDP.  I'll open a tracker shortly.

In my configuration there is no NAT whatsoever. Is there a way to disable NAT traversal completely, thereby working around this issue for the time being?


- Jeff



On Tue, Sep 25, 2012 at 12:09 PM, Joegen Baclor <[email protected] <mailto:[email protected]>> wrote:

    Jeff, good bug reporting!

    By late negotiation, do you mean INVITE with no SDP? There is a
    known issue with NAT traversal plugin not being able to handle
    this properly.  If you don't mind, please open a tracker in jira
    and attach packet captures.


    On 09/25/2012 11:57 PM, Jeff Pyle wrote:
    Hello,

    At the end of another thread
    <http://list.sipfoundry.org/archive/sipx-users/msg41614.html>
    Tony suggested I try attended transfers and some other parking
    related operations against an Adtran TA900-series gateway.  It
    seemed there had been some friction here in the past.

    I was able to test attended and unattended transfers with sipX
    4.6 on an Adtran TA908E.  The global config option "voice
    transfer-mode network" is required to support REFERs.  Without it
    the results will be undesirable.  With that line, however,
    unattended transfers worked just fine

    Attended transfers yielded no audio when the transfer completed
    if the Adtran is the C-leg of the transfer.  Here's why:

    This is the SDP of the INVITE with Replaces that arrives at the
    Adtran from sipX to wrap up the transfer:

        v=0
        o=- 1348230370 1348230370 IN IP4 172.21.201.60
        s=Polycom IP Phone
        c=IN IP4 172.21.201.60
        t=0 0
        a=sendrecv
        m=audio 2250 RTP/AVP 9 0 8 18 101
        a=rtpmap:9 G722/8000
        a=rtpmap:0 PCMU/8000
        a=rtpmap:8 PCMA/8000
        a=rtpmap:18 G729/8000
        a=fmtp:18 annexb=no
        a=rtpmap:101 telephone-event/8000


    This is correct, telling the Adtran to send audio to
    172.21.201.60 (c= line) on port 2250 (m= line).  172.21.201.60 is
    the IP address of the Polycom who was the A-leg of the call.

    As part of some DSP cleanup ops the Adtran starts a reINVITE
    transaction with late negotiation as soon as the above
    transaction is completed.  The offer SDP on sipX's 200 OK of that
    transaction looks like this:

        v=0
        o=- 1348230370 1348230371 IN IP4 172.21.201.60
        s=Polycom IP Phone
        c=IN IP4 172.21.201.60
        t=0 0
        m=audio 30248 RTP/AVP 9 0 8 18 101
        c=IN IP4 192.168.54.46
        a=rtpmap:9 G722/8000
        a=rtpmap:0 PCMU/8000
        a=rtpmap:8 PCMA/8000
        a=rtpmap:18 G729/8000
        a=fmtp:18 annexb=no
        a=rtpmap:101 telephone-event/8000
        a=x-sipx-ntap:X192.168.54.46-[PUBLIC-IP];54


    Notice the c= and m= lines have changed.  sipX is now telling the
    Adtran to send audio to 192.168.54.46, the IP address of the sipX
    instance itself. This is why the A-leg Polycom at 172.21.201.60
    doesn't receive any audio after the transfer - sipX told the
    Adtran to send the audio elsewhere.

    Any idea why sipX might do that?

    As a bandaid, one can prevent the Adtran from sending the
    reINVITE by adding "no prefer reinvite-without-sdp" to the voice
    trunk configured to talk to sipX.  This command is available only
    in prerelease code at the moment.  I believe it will be GA by the
    end of the month.


    - Jeff




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