Is anyone running Lync over a WAN (multiple sites) using Cisco and having quality issues? RRS feed

  • Question

  • I have a relatively large organization , 80 remote sites and two datacenters.  All my Lync components are in a single datacenter.  My remote sites are connected via MPLS (frame-relay encapsulation).  Each remote site is only about 3-10 users.  These sites are typically in rural areas. They each have a single T1 to the MPLS cloud.   The datacenter has 2x DS3's. On the regular I have about 12 branches continually complain about call quality (volume dips, echoing, etc).  Since microsofts official stand on QoS is that 'its not needed at the network layer" I am having a hard time finding out what people are doing for qos.  I have verified the clients are marking (in our case 0x2E or DSCP 46).  Our MPLS routers at the remote sites as well as at the data center have policy maps to trust this DSCP and stick it the EF queue. Our core at the datacenter is a stack of Cisco 3750's.  This stack currently does not have any QoS settings.  Anyone have any guidance ?
    Wednesday, June 20, 2012 6:19 PM


All replies

  • Hi,

    QoS for Lync is certainly recommended internally on your network. While Lync does a lot to overcome issues where you can not deploy QoS like the internet it is recommended to deploy QoS and integrate Lync into the QoS Architecture.

    If the client is marking correctly you will also need to ensure that the network is trusting your endpoints. By default Cisco switches set DSCP markings back to default. Have you verified that the RTP packets are in fact hitting the queues you have setup?

    You may also want to look at the devices people are using at those branches. More often than not a poor audio experience can be linked to using non-certified/optimal devices.




    Wednesday, June 20, 2012 7:29 PM
  • I would recommend deploying the Monitoring Role to give you more insight into what is causing the poor user experience.


    • Proposed as answer by Sean_Xiao Monday, June 25, 2012 5:54 AM
    • Marked as answer by Sean_Xiao Friday, June 29, 2012 2:50 AM
    Wednesday, June 20, 2012 8:09 PM
  • Agree with Jamie. The monitoring server will also give insight into the devices being used and also versioning of the client along with network stats.

    Great recommendation.




    Wednesday, June 20, 2012 8:58 PM
  • Yes, I have deployed Lync Monitoring...everything is green. Round trip is excellent, MOS is high, etc.  We have monitoring software at the datacenter and we show no dropped packets.  Our branches are informing us immediately after a poor quality call so I get to look at whats going on with the network at that exact time.  I know its not QoS related as all Wan links are not even close to saturation at the time of the bad call. These branches are located in extremely rural areas.  Perhaps I should start focusing on our SIP provider.  I've engaged them in the past and they have told me everything is ok ...I've never escalated past a level 1 tech.  Perhaps they are having a PSTN-> SIP handoff issue?  Other than that I have no idea whats been causing these quality issues (i cant even replicate them when calling the branches). I have been dealing with it since Feb.
    Friday, June 29, 2012 1:51 PM
  • So I take it that the call quality issues only happen to the PSTN over SIP trunk to the SP. Internal peer to peer calls work just fine? Do you have media bypass turned on?

    Any additional details you can give will be helpful to the folks in the forum.


    Friday, June 29, 2012 3:22 PM
  • Hi 

    I an running Lync with a 2 Main Pool sites plus 9 Branch SBA sites and all connected via WAN with Branches having between up to 250 users and as low as 15 users

    They are connected via WAN links to the Main site with speeds ranging from 2 Mg to 10 Mg Circuits and with PSTN in each sites but all internal lync calls are going via the WAN

    We are an exclusive Cisco Shop with 3750 POE Switches and Cisco Routers in each site

    We are doing QOS on the Switch \ Router VLAN level rather than through LYNC, we have employed a Voice VLAN and Data VLAN setup with the majority of our users using Lync Phone Edition Phones which allows us to run this setup

    We have had zero issues with Call Quality in our setup and it seems this setup is working really well especially with Voice \ Data VLAN


    Thursday, July 5, 2012 12:45 PM
  • @ Maz124ss,

    I would be interested in what guide or steps you took to implement your QoS policy. 

    Any info would be greatly appreciated. 

    Friday, July 6, 2012 5:07 PM
  • voipnorm...99 out of 100 calls to/from our branches are inbound from the PSTN over a verizon SIP trunk into a response group.  I know its not the response group service causing the prob though.  This last week we have made a few qos tweeks on our mpls routers and it seemed to have helped.  I will report back later next week.

    @Maz124ss.....I second jdelatorre's request for your qos configs :)

    Sunday, July 8, 2012 8:42 PM