Jeff, I think the confusion is that some sip components are on the
192.168.53.x network, while others are on 172.21.201.x network.  In your
description below, you state "which routes", which is indicating there is a
router on the network, and the IP addressing would indicate they are on
different networks.  A router is required to route from one network to the
other network.   

 

NAT would be associated with a router - hence the reason why the questions
around where the router is.

 

one Polycom extension 1821 at 172.21.201.39 calls another, 7821, at
172.21.201.60. 7821 does an attended transfer to 2164550549, which routes
through the Adtran gateway at 192.168.53.11. The sipX system itself is at
192.168.54.46.

 

From: [email protected]
[mailto:[email protected]] On Behalf Of Jeff Pyle
Sent: Tuesday, September 25, 2012 10:35 AM
To: Joegen Baclor
Cc: Discussion list for users of sipXecs software
Subject: Re: [sipx-users] Incorrect SDP from sipX after xfer completion

 

Joegen,

 

I fully understand my network so I don't see where the problem is.  :)

 

All the details, including an adequate topology description, are now in
XX-10464 <http://track.sipfoundry.org/browse/XX-10464> .




- Jeff

 

On Tue, Sep 25, 2012 at 12:57 PM, Joegen Baclor <[email protected]> wrote:

Jeff,

I might be missing something but the SDP you pasted



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



172.21.201.60 being the original IP of the polycom

and

192.168.54.46 being the IP of sipX

I assumed that there is a firewall linking these two networks.  Maybe a
packet capture and a topology description would save us the need to
speculate much :-)





On 09/26/2012 12:45 AM, Jeff Pyle wrote:

Joegen, 

 

In my case all the SIP-speaking components are directly routable to each
other with no firewalls and therefore no NAT in between.  I don't understand
what you mean by "sipX being behind a firewall".  Is that relevant to the
NAT traversal issue you mentioned?

 

 

- Jeff



On Tue, Sep 25, 2012 at 12:42 PM, Joegen Baclor <[email protected]> wrote:

>> 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]> 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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