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Outband Call Routing isssue RRS feed

  • Question

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    Hello!

    We have OCS 2007 R2 deployed in our organization.

    We have telephony integration by SIP Trunk with CISCO Call Manager (CCM) 4.3.X, and it worked  fine.. But month ago an interesting issue appeared: users become getting errors when making outbound calls to PSTN (witch goes  through CCM) the text of the error from Front-End

     

    An attempt to route to a gateway failed.

     

    Could not route to Gateway ocs-med01-s8k.softline.main:5061, the attempt failed with response code: Timeout.

    Failure occurrences: 55, since 6/11/2010 2:18:39 PM.

    Cause: A gateway failed to respond to a request within allotted time or was unable to route the request due to some error.

    Resolution:

    Check whether the specified gateway is up and is properly configured.

     

    "It can be from five to ten times a day in a different time, so no systematicity"

     

     

    On the Mediation Server we have no errors at all. We have nagious configured to ping and telnet mediation server on services ports (no errors from it).

     

    Mediation server have 2 interfaces : 10.3.0.183 - To OCS & 10.3.0.184 - To CCM(10.3.1.10)

     

    When I checked logs from mediation (when making outgoing call ) I saw that packets  from 10.3.0.183 go to 10.3.1.10

    Is it normal??

     

    When I tried logically separate these interfaces in different VLANs - all calls to PSTN fails

     

    Below you can find logs from Mediation when users makes outbound call and it fails

     

    TL_INFO(TF_PROTOCOL) [5]03F4.08F0::06/21/2010-09:10:45.264.000183a4 (S4,SipMessage.DataLoggingHelper:sipmessage.cs(531))

    >>>>>>>>>>>>Outgoing SipMessage c=[<SipTcpConnection_1B57174>], 10.3.0.183:59117->10.3.1.10:5070 - I think that it must go from 10.3.0.184

    INVITE sip:0973662036@10.3.1.10;user=phone SIP/2.0

    FROM: <sip:XXXX@ocs-MED01-s8k.softline.main;user=phone>;epid=224AC0267C;tag=352f4d9390

    TO: <sip:YYYYY@10.3.1.10;user=phone>

    CSEQ: 1005 INVITE

    CALL-ID: dc9b4b29-e79d-4c1f-a838-fbe17428984d

    MAX-FORWARDS: 70

    VIA: SIP/2.0/TCP 10.3.0.183:59117;branch=z9hG4bK88ace372

    CONTACT: <sip:ocs-MED01-s8k.softline.main:5060;transport=Tcp;maddr=10.3.0.183;ms-opaque=0420ec557f993770>

    CONTENT-LENGTH: 323

    SUPPORTED: 100rel

    USER-AGENT: RTCC/3.5.0.0 MediationServer

    CONTENT-TYPE: application/sdp; charset=utf-8

    ALLOW: ACK

    Allow: CANCEL,BYE,INVITE,PRACK,UPDATE

    v=0

    o=- 1408 1 IN IP4 10.3.0.183

    s=session

    c=IN IP4 10.3.0.183

    b=CT:1000

    t=0 0

    m=audio 60390 RTP/AVP 97 101 13 0 8

    c=IN IP4 10.3.0.183

    a=rtcp:60391

    a=label:Audio

    a=rtpmap:97 RED/8000

    a=rtpmap:101 telephone-event/8000

    a=fmtp:101 0-16

    a=rtpmap:13 CN/8000

    a=rtpmap:0 PCMU/8000

    a=rtpmap:8 PCMA/8000

    a=ptime:20

    ------------EndOfOutgoing SipMessage

     

    After that message Mediation have incoming

     

    SIP/2.0 100 Trying

     

     

    <<<<<<<<<<<<Incoming SipMessage c=[<SipTcpConnection_1B57174>], 10.3.0.183:59117<-10.3.1.10:5070

    SIP/2.0 503 Service Unavailable

    FROM: <sip:XXX@ocs-MED01-s8k.softline.main;user=phone>;epid=224AC0267C;tag=352f4d9390

    TO: <sip:YYYYY@10.3.1.10;user=phone>;tag=17352260

    CSEQ: 1005 INVITE

    CALL-ID: dc9b4b29-e79d-4c1f-a838-fbe17428984d

    VIA: SIP/2.0/TCP 10.3.0.183:59117;branch=z9hG4bK88ace372

    ALLOW-EVENTS: telephone-event

    CONTENT-LENGTH: 0

    DATE: Mon, 21 Jun 2010 09:11:29 GMT

    ------------EndOfIncoming SipMessage

     

     

    So I have no ideas what can cause these issues..

    My assumptions was that the problem can be if codecs that use Mediation and CCM are different, but they are OK.

    Or if some troubles with SIP Trunk, but if  they  were all calls failed..

    I can expect that the trouble occurs when making outbound calls the Mediation server talks to CCM from IP 10.3.0.183 instead of 10.3.0.184

     

    Please help me to resolve this problem!

     

    Appreciate your help,

    Denis Golovatyuk

    Tuesday, June 22, 2010 10:14 AM

Answers

  • Hello!

    I'll try your solution- it help me only with one NIC one Mediation! (now calls go through one interface)

    The other side of the question was the difference between protocols and codecs witch use Mediation when speeking to CCM (1) & when CCM speeking to PSTN(2)

    (1) Mediation use TCP proto an G711ulaw codec to speak with CCM

    (2) CCM use UDP proto and G711alaw

    So, the issue was in codec difference and in times when CCM chose the codec to communicate with PSTN, on dialpeer witch points to PSTN was the option - voice class codec 1 (list of codecs, and gateway choose one with witch it will communicate).  The first codec in list was G711ulaw instead of G711alaw, because PSTN provider understands only it. So we fixed it with command codec G711alaw.

    So, by now it works without errors, but i'll see tommorow and make a decision: were these changes write or not )

    Thanks for your help!

    Best regards,

    Denis Golovatyuk

    Wednesday, June 23, 2010 5:49 PM

All replies

  • So, this is a known issue when you have a mediation server with two NICS on the same subnet.

     

    See here: http://social.microsoft.com/Forums/en/communicationsservertelephony/thread/5e4035ba-f454-426c-8c03-6dff54a9b6f0

     

    The problem is in how OCS will choose to send traffic out to ccm, it will not always be out the same interface, since they are on the same subnet it is up to the windows binding order to choose.

     

    You will have to either have one NIC, or do two NICS, one of them being on a completely seperate subnet.

     

    There is a good description in the link I posted above.

     

     


    Randy Wintle | MCTS: UC Voice Specialization | Winxnet Inc
    • Proposed as answer by Andrii Veselov Wednesday, June 23, 2010 7:18 AM
    Wednesday, June 23, 2010 12:57 AM
  • Hello!

    I'll try your solution- it help me only with one NIC one Mediation! (now calls go through one interface)

    The other side of the question was the difference between protocols and codecs witch use Mediation when speeking to CCM (1) & when CCM speeking to PSTN(2)

    (1) Mediation use TCP proto an G711ulaw codec to speak with CCM

    (2) CCM use UDP proto and G711alaw

    So, the issue was in codec difference and in times when CCM chose the codec to communicate with PSTN, on dialpeer witch points to PSTN was the option - voice class codec 1 (list of codecs, and gateway choose one with witch it will communicate).  The first codec in list was G711ulaw instead of G711alaw, because PSTN provider understands only it. So we fixed it with command codec G711alaw.

    So, by now it works without errors, but i'll see tommorow and make a decision: were these changes write or not )

    Thanks for your help!

    Best regards,

    Denis Golovatyuk

    Wednesday, June 23, 2010 5:49 PM