Announcement

Collapse
No announcement yet.

Call Quality Issues in Lync 2010

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Call Quality Issues in Lync 2010

    We installed Lync 2010 two weeks ago.

    First week we were dropping calls, around 10 a day. Voice quality was phenomenal.

    Second week, one of the other techs setup a new SBS at our test location, didn't work and reverted back. Call quality then went down the tubes and skips frequently, definitely packet loss there.

    For the last week, we've been fighting call quality issues.

    This is our setup:
    Cox Communications SIP trunk
    Asterisk PBX
    Lync Server

    Location A - Corporate - Has our Front End server
    Location B - Remote Location - Has our PBX, SIP trunk and SBS for Lync

    Location's A & B are connected to each other via a SonicWALL VPN.

    Location A has 100Mbps u/d connection and Location B has 50Mbps u/d connection.

    Now, here are the things we've done to eliminate different things:
    1) Cox came out and tested both the fiber connection and the SIP trunk at Location B. Calls via the SIP trunk direclty are crystal clear.
    2) We've segmented Lync, Asterisk and the SIP trunk on a VLAN to get them out of "heavy" local network use.
    3) Moved Asterisk to a system with a legacy NIC.
    4) Monitoring shows very little, if anything that would indicate cause for concern.

    Here's the scoop:
    1) Lync to Lync calls on Polycom CX600 calls from within Location B are crystal clear
    2) Lync to Lync calls on Polycom CX600 calls from Location B to Location A and Location A to Location B (over the VPN miind you) are crystal clear.
    3) Calls from Lync to Outside World are choppy. The Lync user is clear to the person on the other end, yet the person on the other end is choppy.

    We are leaning towards it being an Asterisk problem but I don't know enough about Asterisk to be 100% sure.

    I'm not sure what to do at this point to fix the voice quality.

    Any ideas from any of you wizards?
    I'd rather check my Facebook than face my checkbook...

    Thanks,
    Todd

  • #2
    Re: Call Quality Issues in Lync 2010

    Originally posted by todd231 View Post
    We installed Lync 2010 two weeks ago.

    First week we were dropping calls, around 10 a day. Voice quality was phenomenal.

    Second week, one of the other techs setup a new SBS at our test location, didn't work and reverted back. Call quality then went down the tubes and skips frequently, definitely packet loss there.

    For the last week, we've been fighting call quality issues.

    This is our setup:
    Cox Communications SIP trunk
    Asterisk PBX
    Lync Server

    Location A - Corporate - Has our Front End server
    Location B - Remote Location - Has our PBX, SIP trunk and SBS for Lync

    Location's A & B are connected to each other via a SonicWALL VPN.

    Location A has 100Mbps u/d connection and Location B has 50Mbps u/d connection.

    Now, here are the things we've done to eliminate different things:
    1) Cox came out and tested both the fiber connection and the SIP trunk at Location B. Calls via the SIP trunk direclty are crystal clear.
    2) We've segmented Lync, Asterisk and the SIP trunk on a VLAN to get them out of "heavy" local network use.
    3) Moved Asterisk to a system with a legacy NIC.
    4) Monitoring shows very little, if anything that would indicate cause for concern.

    Here's the scoop:
    1) Lync to Lync calls on Polycom CX600 calls from within Location B are crystal clear
    2) Lync to Lync calls on Polycom CX600 calls from Location B to Location A and Location A to Location B (over the VPN miind you) are crystal clear.
    3) Calls from Lync to Outside World are choppy. The Lync user is clear to the person on the other end, yet the person on the other end is choppy.

    We are leaning towards it being an Asterisk problem but I don't know enough about Asterisk to be 100% sure.

    I'm not sure what to do at this point to fix the voice quality.

    Any ideas from any of you wizards?
    Do you have the Lync monitor role installed? If not install it now. The information you get from it is simply excellent for issues like this. It will tell you precisely what is going on over the wire. In addition you can also use the Lync logging tool which is a protocol analyzer for debugging SIP traffic.
    Is this problem restricted solely to CX600's? Or does the Lync softphone client have the same issue? As if its only the handsets that have a problem it may be DSCP tagging that is causing the problem as its enabled by default for handsets and your firewall may be interpreting the traffic incorrectly.

    http://blog.schertz.name/2011/08/lync-qos-behavior/

    Which version of Asterisk are you running? As you can turn up the verbosity of the logging from the CLI (or GUI depending on the version).Much like Lync the logs are very detailed and will give you a good indication where the problem lays.

    Comment

    Working...
    X