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Call transfers from response group fail after gateway failures

    Question

  • Hi,

    We have  a SIP trunk for our PSTN calls with Lync.

    Sometimes the gateway fails:

    A call to a PSTN number failed due to non availability of gateways.
    ...

    Cause: All gateways available for this call are marked as down.

    Resolution:

    Verify that these gateways are up and can respond to calls.

    A few minutes later the gateway is up again:

    A PBX gateway is now responding to requests after some failures.

    Gateway name:XXXXX, Number of failures seen 1

    Everything should be fine at this point, but all calls received via a response group can not be transfered. There is no error displayed in the Lync client, the call just disappears and the caller is left on hold (music).

    We need to restart the Response Group service and the Mediation service to correct the problem.

    Any ideas? Is this a bug?

    Regards

    Francois Kreutz


    FK

    Friday, March 23, 2012 9:53 AM

Answers

All replies

  • UPDATE:

    I checked the monitoring reports. For a "failed" transfer the diagnostic header is:

    13004; reason="Request was proxied to one or more registered endpoints";
    source="zzzz.priv"; Count="3"; appName="InboundRouting"

    Which endpoint???

    Not really sure this is related to the gateway failures.

    Regards


    FK

    Friday, March 23, 2012 10:38 AM
  • are you using enterprise or standard? colocated mediation or standalone pool? what CU update do you have installed?

    If this post answered your question, Mark As Answer If this post was helpful, Vote as Helpful http://lyncme.blogspot.com

    Friday, March 23, 2012 5:13 PM
  • Hi Tim,

    Standard edition, colocated mediation, CU4.

    Thanks

    Francois


    FK

    Friday, March 23, 2012 7:28 PM
  • Who is your trunk provider? do they use TCP ? what are you using to route the SIP trunk to your mediation?

    If this post answered your question, Mark As Answer If this post was helpful, Vote as Helpful ---------------------------------------------------------- http://lyncme.blogspot.com

    Friday, March 23, 2012 7:33 PM
  • It's a french provider (OpenIP), yes they use TCP.

    We have a dedicated SDSL 2Mb connection, with an ADSL backup. Cisco routers if I remember well.


    FK

    Friday, March 23, 2012 7:40 PM
  • Hi

    Maybe you can also investigate on why the gateway goes down (often ?): if the gateway is not properly configured to send 183 messages to Lync during call setup, Lync will declare the call failed and after a certain amont the gateway will be declared down. What is the gateway model ?

    Saturday, March 24, 2012 8:44 AM
  • HI,

    Do you transfer the call to a PSTN number or other Lync users?

    PLease have a try use the internal lync client to call the response group and check the call can be transfered by the agent user.


    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 members reading the thread.

    Monday, March 26, 2012 9:48 AM
  • Hi,

    The call is transfered to an other Lync user. We'll do the internal test next time we have the problem.

    We are also investigating the gateway problems.

    I'll keep you updated.

    Thanks to all for the input.

    Regards

    Francois


    FK

    Monday, March 26, 2012 10:44 AM
  • Hi

    Update on my investigations:
    When our SIP provider cannot route a call (incorrect number for example), it sends a 503 response code (“Gateway responded with 503 Service Unavailable”) which Lync interprets as “A call to a PSTN number failed due to non availability of gateways”.

    Can anyone confirm that 503 is the correct response code in such a situation?

    Regarding our response group problem, I found this post:
    http://int.social.technet.microsoft.com/Forums/en-CA/ocsvoice/thread/d6b06d43-2749-429f-a096-9276e6500ac3

    We have a bunch of Snom 300’s, we’re currently upgrading the firmware to see if the response group problem disappears.

    Thanks

    Francois


    FK

    Tuesday, March 27, 2012 1:38 PM
  • Hi,

    Any update?

    Is your problem solved by the upgrading firmware?


    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 members reading the thread.

    Friday, March 30, 2012 11:07 PM
  • Hi Sean,

    Unfortunately it's not related to the Snom phones.

    We are still investigating...


    FK

    Thursday, April 05, 2012 4:23 PM
  • Hi,

    We still have problems with the response groups.

    The transfer problem occured yesterday and I did an internal test: the transfer also fails.

    I also discovered another problem while doing some tests (when transfers are working):

    • I call a response group using the Lync client (internal call)
    • The agent transfers the call to another internal Lync user A
    • The call is connected, A can hear me, but I can't hear A

    Just to make sure I created a new response group and the one way audio problem is the same.

    I Wiresharked the scenario above, the only strange thing is that there seems to be a lot of trafic between my Lync client and the Edge server (but it could also be normal, I have external contacts).

    I don't know if all these response group problems are related. I'm having a really hard time sorting this out because there are no errors in the Lync logs or in the monitoring reports.

    I would appreciate any help.

    Thanks

    Francois


    FK


    Thursday, April 12, 2012 3:41 PM