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Unable to make outbound calls while SBA is offline RRS feed

  • Question

  • Hello,

    We have a Central Site setup for IM, presence, and conferencing with two collocated FEs.  We also have a branch site running an SBA which is also enabled for Enterprise Voice.  Everything is working fine locally within the branch site when all services are online on the SBA.  If we shut down the Lync services on the SBA, the users properly fail over to the backup registrar in the Central Site.  However, they can no longer call outbound.  I ran logger/snooper on the FEs and it appears that the Mediation in the Central Site (where users are registering) is directing the signaling and media to the SBA in the branch site rather than the AudioCodes gateway.  I have configured the sites and subnets in the Lync network configuration and enabled media bypass for this site.
    I'm sure this is a configuration issue.  Can someone provide some guidance around what may be causing this?
    Thanks,
    Phil


    • Edited by Phil_Sharp Tuesday, January 10, 2012 4:20 PM
    Tuesday, January 10, 2012 4:20 PM

Answers

  • Oh I get it.  The Audiocodes is still functioning, so it should still be able to route calls.  However, the same rules still apply.  You need to setup alternate routes to the Audiocodes gateway using the mediation server in the central site.  

    You'll need to define a second DNS name for the audiocodes gateway in your topology, and assign it to the mediation server in the central site.  If you try to use the same DNS name or IP address, the topology builder will throw an error.  So, all you need is multiple DNS A records pointing to the same IP.  Once you've done that, then the usages I mentioned in the earlier post still apply.

     

    Ken

    • Marked as answer by Phil_Sharp Wednesday, January 11, 2012 4:19 AM
    Tuesday, January 10, 2012 8:00 PM

All replies

  • Hey Phil,

    Even if the users failover and register against the central server, they will still be assigned the voice policy of their home site.  You need to assign phone usages for the central site to the branch site voice policy for voice traffic to still work.  Put the central site usages below the branch site ones.   This way, if the SBA route isn't available, phone calls will route to the next available usage, which should be the central site.  Here's an example of what your branch site voice policy could look like (btw, this will also give you least cost routing):

    Branch-Local-Usage

    Central-Local-Usage

    Branch-National-Usage

    Central-National-Usage

    Branch-International-Usage

    Central-International-Usage

     

    See my blog post on usages and routes for more info...http://ucken.blogspot.com/2011/01/enterprise-voice-best-practices-in-lync_21.html (PSTN Usage Ordering section)

     

    Ken

     

     

    Tuesday, January 10, 2012 4:56 PM
  • That's kind of what I thought, but I don't have voice gateways in the Central Site yet.  Is that the only way it will work?  I would have thought that it would look at what is associated with the Voice Policy assigned, then route the calls based on that (regardless of where they are registering).
    Tuesday, January 10, 2012 6:32 PM
  • Oh I get it.  The Audiocodes is still functioning, so it should still be able to route calls.  However, the same rules still apply.  You need to setup alternate routes to the Audiocodes gateway using the mediation server in the central site.  

    You'll need to define a second DNS name for the audiocodes gateway in your topology, and assign it to the mediation server in the central site.  If you try to use the same DNS name or IP address, the topology builder will throw an error.  So, all you need is multiple DNS A records pointing to the same IP.  Once you've done that, then the usages I mentioned in the earlier post still apply.

     

    Ken

    • Marked as answer by Phil_Sharp Wednesday, January 11, 2012 4:19 AM
    Tuesday, January 10, 2012 8:00 PM
  • ....and then there is TLS.  TLS is configured between the SBA and AudioCodes, and I'm not sure that the AudioCodes would support multiple certs (for the other name).  This would be a non-issue if we could use the same PSTN gateway in multiple sites and Lync would route based on the priority/availability of the Routes configured in the Voice Policy.  Ah well, the AudioCodes in the Central Site will be installed this week so I guess we'll have to hold out until then.

     

    If we were just using TCP, alternate names would definitely do the trick.

     

    Thanks for your help.

    Wednesday, January 11, 2012 4:19 AM