10 seconds delay before call ringing

Hi, I have a 10 second before a call, the lync user making the call hears "blip-blip-blip...." and then finally a ring tone.  This is for both Lync2Lync calls and for lync-PSTN and PSTN-lync calls. It seems that this delay is introduced internally on the server Mediation at routing level (Mediation -> FE). In the architecture there are 2 FE with a mediation inside and a load balancer.

Do you have an suggestions on how to eliminate the delay issue?

Thanks, Massimo

October 31st, 2012 5:39pm

Is there an edge server in the environment?  If so, can the clients route to it with the appropriate ports?
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October 31st, 2012 8:25pm

Can you clarify what devices you are using. For example, is the "blip-blip" being heard on Lync phone edition only, the Lync client only or both? This sounds like a known issue with Response Groups and Lync phone edition but that does not match your description. Also, what gateway are you using on the PSTN side? Can you capture a server side log (SIPStack and S4) when this happens as this might offer additional information.
October 31st, 2012 9:13pm


Would you please verify that your Dial plan and Translation rules are set correctly?I have seen an old case with similar issue caused by wrong Dial Plan and Translation rules,details please check http://social.technet.microsoft.com/Forums/en-US/ocsvoice/thread/f2aadf63-3125-49cf-8b0f-4645c214e671

Besides,you have Hardware load balancer deployed,please also check the configuration on it to see if there are any problems.You can try to remove the HLB and see if the call delay still exists to narrow down the issue.

If it's hard to find the cause you can enable Lync client logging and server logging on your Mediation server and FE server(Select S4,SipStack and MediationServer) and use snooper to analyze the trace log for more specific information,you also can run NetMon or Wireshark on the client and server to check the network trace to get more information for troubleshooting.



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November 1st, 2012 12:55pm

Thanks to all.

In the enviroment these is the edge server. All the route and port are correct. The client is a PC and I hear the sound from the PC client. At the PBX side I hear nothing for 10 sec, after the ring tone and instantly the pc client ring.

If I remove the association to the edge server in the topology the delay disappered....




November 6th, 2012 1:53pm


How many IP addresses do you have assigned on your Edge Server's internal Nic?

I had a very similar issue and it was caused by the Edge server. I had 3 IP bound to  the internal interface and that interface registered the FQDN for the server on all 3 IPs in DNS. What I done to fix it is I went to the advance IPv4 properties and removed the check mark for "Allow this interface to register its connections in DNS". I then went to my internal DNS and removed all the A records for the Edge servers a configured a static record for the Server on its Primary IP.

This worked almost instantly as I pushed a DNS replications and flushed my DNS and the DNS of the Lync servers.

Hope this helps!

Kind regards


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November 8th, 2012 7:47am

Thanks Joe,

it isn't my case, I have only 1 IP address in the internal interface and a static DNS record (also the mark to the DNS registration is unchecked).

I'm investigating about network comunications between client and edge server to be sure that all the ports in the firewall are open.

I'll keep you all updated.



November 8th, 2012 2:11pm

We have found a packet dropping (STUN port 3478) in the HLB (Cisco ACE) when the communication is between the pc client and the edge host. Only the communication between the client and the VIP is working. The actual ACE configuration is the same of the old installation of OCS.

Sharon has been right in the previous post. We are working to find the right configuration, do you have any suggestions?



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November 12th, 2012 6:38pm


I have no experience to deploy Cisco ACE with Lync,but there are lots of useful blog posts may help you work out the issue.



Note: Microsoft is providing this information as a convenience to you. The sites are not controlled by Microsoft. Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. Please make sure that you completely understand the risk before retrieving any suggestions from the above link.



November 13th, 2012 4:36am

Hi Sharon,

unfortunately the configurations are related to the traffic http and https (the documents don't refer to the balance of the STUN port 3478). Are there any guideline for balancing even UDP port 3478?



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November 13th, 2012 2:40pm


I am having the same problem. I have Lync 2010 and Lync 2013 mixed environment. if a user is hosted on lync 2013 , there is a delay of 10 seconds before a ring tone and if its Lync 2010 user there is no delay before ring. 

this happens both from Lync 2013 user dialing to PSTN or from PSTN dialing in to Lync 2013 user.



July 4th, 2013 12:21pm

Hi <o:p></o:p>

Long delay can happen if your call initiation in not
straightforward (Edge, ICE, etc discovery, or response groups are involved).<o:p></o:p>

Simplifying the discovery (e.g. disable external
access) will reduce the delay.<o:p></o:p>



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July 6th, 2013 7:26am

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