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Polycom CX600 Cannot Transfer to mobile

    Question

  • Working on a system with a SIP Trunk to ThinkTel (Sip trunk terminates through a NAT firewall direct to a dedicated mediation server)

    2 Scenarios.

    1)  User at home with Lync client either on Windows or OS X - receives an external call - if they do the external transfer to mobile, it works just fine.

    2)  User at home with Lync Client on either Windows or OS X - who also has an operational CX600 Polycom Phone running the latest firmware (7577.4047) .    If this user answers the phone and then transfers to mobile - the mobile phone rings - the user answers, no media is sent, and after 5-6 seconds the mobile phone call drops, and the phone says "transfer call unsuccessful" and the call is back to normal.  

     This sounds like a media streaming issue for sure, the call comes up, but then media negotiation fails.   I did run snooper and I see some EMPTY SDP messages.  

    REFER is disabled, and I have rebooted all servers to ensure it took.

    • Edited by Justin Cohen Wednesday, February 08, 2012 2:13 PM more details.
    Wednesday, February 08, 2012 2:12 PM

Answers

  • Hi,Justin,

    I doubt it's media codec issue,I saw you are using G.711 u-law in the Log when transfer call from Polycom to Mobile, please verify that your Thinktel Trunk  and Lync client/devices use the consistent code.

    Thinktel only supports the following codes:

    - G.711 - Pulse code modulation (PCM) of voice frequencies on an 64 kbps channel. mu-Law companding (PCMU) and a-Law companding (PCMA)

    - G.726-32 / G.721 - 32 kbit/s adaptive differential pulse code modulation (ADPCM)

    - G.729 - Coding of speech at 8 kbit/s using conjugate-structure algebraic-code-excited linear-prediction (CS-ACELP), including annex A and B.

    Lync Server 2010 supports only G.711 a-law (used primarily outside North America) and G.711 μ-law (used in North America)

    Regards,

    Sharon


    Sharon Shen

    TechNet Community Support

    ******************************************************************************************************************************************************* Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community memb

    Friday, February 10, 2012 10:27 AM
    Moderator
  • Hi,there,

    Sorry for responsing you so late due to not aware of your updates.

    "Consistent Codec“ I mean is that they must use the same codec when negotiated with each other,base on your description it seems the g.711 u-law cannot be receieved by one side.Maybe you can talk with your ThinkTel trunk provider to verify if they disable u-law negotiation.

    Regards,

    Sharon


    Sharon Shen

    TechNet Community Support

    ***************************************************************************************************************************************************************************** Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial t

    Friday, February 24, 2012 10:26 AM
    Moderator

All replies

  • hi,

    If the user picks up the call , it mean you should the see the SIP Dialog complete with a 200 OK and ACk. If not, what is the failure response code for this transferred call?

    You could take a packet capture and analyse it.

    Wednesday, February 08, 2012 7:23 PM
  • I am looking but I don't really see where the issue might be...

    Here is some scenarios

    1)  cx600 to cx600  WILL transfer to mobile

    2)  External to CX600 will NOT transfer to mobile

    3)  External to Lync Client WILL transfer

    Here is the trace of the call that drops..  (private data changed)

    |Time     | 10.x.x.x                       | 206.x.x.x                     |
    |         |                   | 206.x.x.x    |                   
    |41.447   |         INVITE SDP (REDRTPType-97 telephone-eventRTPTy...101 CN g711U)          |                   |SIP From: "Juser"<sip:+16475551212@mediation.lync.com;user=phone To:<sip:+14165551212@206.x.x.x.x;user=phone
    |         |(56441)  ------------------>  (5060)   |                   |
    |41.450   |         100 Giving a try              |                   |SIP Status
    |         |(56441)  <------------------  (5060)   |                   |
    |43.759   |         183 Session Progress SDP (g711U telephone-even...PType-101)          |                   |SIP Status
    |         |(56441)  <------------------  (5060)   |                   |
    |43.761   |         PRACK     |                   |                   |SIP Request
    |         |(56441)  ------------------>  (5060)   |                   |
    |43.794   |         RTP (g711U)                   |                   |RTP Num packets:378  Duration:11.313s SSRC:0x1BC32F6
    |         |(56590)  <--------------------------------------  (58624)  |
    |43.810   |         200 OK    |                   |                   |SIP Status
    |         |(56441)  <------------------  (5060)   |                   |
    |49.639   |         200 OK SDP (g711U telephone-eventRTPType-101)          |                   |SIP Status
    |         |(56441)  <------------------  (5060)   |                   |
    |49.640   |         ACK       |                   |                   |SIP Request
    |         |(56441)  ------------------>  (5060)   |                   |
    |55.110   |         INVITE SDP (g711U telephone-eventRTPType-101)          |                   |SIP From: "JUser"<sip:+16475551212@mediation.lync.com;user=phone To:<sip:+14165551212@206.x.x.x;user=phone
    |         |(56441)  ------------------>  (5060)   |                   |
    |55.113   |         100 Giving a try              |                   |SIP Status
    |         |(56441)  <------------------  (5060)   |                   |
    |55.138   |         RTP (g711U)                   |                   |RTP Num packets:1  Duration:0.000s SSRC:0x1BC32F6
    |         |(56590)  <--------------------------------------  (58624)  |
    |55.220   |         200 OK SDP (g711U telephone-eventRTPType-101)          |                   |SIP Status
    |         |(56441)  <------------------  (5060)   |                   |
    |55.223   |         ACK       |                   |                   |SIP Request
    |         |(56441)  ------------------>  (5060)   |                   |
    |56.912   |         INVITE SDP (g711U telephone-eventRTPType-101)          |                   |SIP From: "JUser"<sip:+16475551212@mediation.lync.com;user=phone To:<sip:+14165551212@206.x.x.x;user=phone
    |         |(56441)  ------------------>  (5060)   |                   |
    |56.917   |         100 Giving a try              |                   |SIP Status
    |         |(56441)  <------------------  (5060)   |                   |
    |56.998   |         RTP (g711U)                   |                   |RTP Num packets:233  Duration:6.960s SSRC:0x1BC32F6
    |         |(56590)  <--------------------------------------  (58624)  |
    |57.024   |         200 OK SDP (g711U telephone-eventRTPType-101)          |                   |SIP Status
    |         |(56441)  <------------------  (5060)   |                   |
    |57.026   |         ACK       |                   |                   |SIP Request
    |         |(56441)  ------------------>  (5060)   |                   |
    |57.601   |         RTP (g711U)                   |                   |RTP Num packets:318  Duration:6.339s SSRC:0x19BA9DCE
    |         |(56590)  -------------------------------------->  (58624)  |
    |63.947   |         BYE       |                   |                   |SIP Request
    |         |(5060)   <------------------  (48523)  |                   |
    |63.950   |         200 OK    |                   |                   |SIP Status
    |         |(5060)   ------------------>  (48523)  |                   |



    • Edited by Justin Cohen Wednesday, February 08, 2012 11:59 PM
    Wednesday, February 08, 2012 11:34 PM
  • Hi,Justin,

    I doubt it's media codec issue,I saw you are using G.711 u-law in the Log when transfer call from Polycom to Mobile, please verify that your Thinktel Trunk  and Lync client/devices use the consistent code.

    Thinktel only supports the following codes:

    - G.711 - Pulse code modulation (PCM) of voice frequencies on an 64 kbps channel. mu-Law companding (PCMU) and a-Law companding (PCMA)

    - G.726-32 / G.721 - 32 kbit/s adaptive differential pulse code modulation (ADPCM)

    - G.729 - Coding of speech at 8 kbit/s using conjugate-structure algebraic-code-excited linear-prediction (CS-ACELP), including annex A and B.

    Lync Server 2010 supports only G.711 a-law (used primarily outside North America) and G.711 μ-law (used in North America)

    Regards,

    Sharon


    Sharon Shen

    TechNet Community Support

    ******************************************************************************************************************************************************* Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community memb

    Friday, February 10, 2012 10:27 AM
    Moderator
  •    Sharon;

    You state "please verify that your Thinktel Trunk  and Lync client/devices use the consistent code."

            Do you actually mean "Consistent Codec"  ?      

        I can make calls in/out in all other cases, and the ThinkTel trunk will negotiate G.711 and in the negotiation you can see G.711 ULAW.  What i'm wondering is if the stream isn't getting from the users phone to the mediation server or something like that.

           The trace doesn't provide enough I don't think

    Friday, February 10, 2012 8:37 PM
  • Does this happen to CX600 which are internal and not external at user home? Have you tried running a trace on the mediation server? Are users at home running any sort of vpn client? So their traffic is "internal", but cx600 traffic is external and passing through the edge server? The fact the the cell phone rings and drops the call 6 seconds later, does sound like a media connectivity problem indeed
    Sunday, February 12, 2012 10:15 PM
  • Does this happen to CX600 which are internal and not external at user home? Have you tried running a trace on the mediation server? Are users at home running any sort of vpn client? So their traffic is "internal", but cx600 traffic is external and passing through the edge server? The fact the the cell phone rings and drops the call 6 seconds later, does sound like a media connectivity problem indeed

    These CX600's are not "internal"  they are located at a users home office - not over a site to site VPN, the users phones connecting over the internet to the edge server.

    I have run a trace on the mediation server, I saw some "No SDP Offer" errors but that is about it the errors were a little difficult to pull apart and figure out who they were talking about but that would also point to Media.

    I agree that the 6 second drop is due to media connectivity, the trace clearly shows audio flow at the mediation gateway (I see 200-300 packets each way)

    When I use WireShark at the Mediation Gateway - I see the cell phone call start - and at the mediation gateway I even see a media stream from ThinkTel (Sip Trunk) to the mediation and I can hear audio there..   But I do not see a reverse stream.

    Monday, February 13, 2012 4:45 PM
  • Hi,there,

    Sorry for responsing you so late due to not aware of your updates.

    "Consistent Codec“ I mean is that they must use the same codec when negotiated with each other,base on your description it seems the g.711 u-law cannot be receieved by one side.Maybe you can talk with your ThinkTel trunk provider to verify if they disable u-law negotiation.

    Regards,

    Sharon


    Sharon Shen

    TechNet Community Support

    ***************************************************************************************************************************************************************************** Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial t

    Friday, February 24, 2012 10:26 AM
    Moderator
  • Hi,Justin,

    Any updates here?

    If you have fixed the issue please kindly share the experience.

    B/R

    Sharon


    Sharon Shen

    TechNet Community Support

    ***************************************************************************************************************************************************************************** Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial t

    Wednesday, February 29, 2012 1:35 AM
    Moderator
  • I have the same problem. Would love to know how you fixed it if possible.

    Aaron Marks

    Tuesday, April 10, 2012 4:05 AM
  • Still no updates?

    I'm basically just hoping that Lync 2013 fixes this at this point. We're having this problem at every site where we've installed Lync Enterprise Voice.


    Aaron Marks

    Saturday, August 25, 2012 8:42 AM