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Skype Hybrid - How to validate QoS? RRS feed

  • Question

  • We have enabled QoS for our Lync/Skype Hybrid Environment; however this is not configured through GPO.

    Our network uses Cisco Prime which apparently detects and applies packet prioritization.

    For last few mins audio quality has been bad, but no much issues with video. Could anyone suggest ways to identify if the QoS is working fine?

    If I run Wireshark trace DSCP values is CS0 which I'm assuming is default forwarding.

    Any advise would be much appreciated. Many Thanks


    • Edited by a2har Friday, December 7, 2018 10:20 AM
    Friday, December 7, 2018 9:55 AM

All replies

  • Dear a2har,

     

    The default “OOBE” (out of the box experience) setting of the Windows OS is to overwrite the DSCP flag value to 0, even if application are set to send out a specific value.

     

    You can enable this setting via the registry

     

    Registry: 

     

    Open the registry editor

    1. Search for “regedit” at the Windows 7 /8 / 10 start menu and double click the “ Regedit  application)
    2. Start the application via the file explorer, browse to the following location “C:\Windows” and start the “regedit.exe” application

     

    When the registry edit is started browse to the following location:

     

    “Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip”

     

     

    Check if the QoS key (Folder) is present else create it.

     

    Create a new DWORD value and name it "Do not use NLA"

     

    Double click newly "Do not use NLA" created value and enter “1” as Hexadecimal or Decimal value

      

    Reboot you system and check if the DSCP flag value is as expected, and not “0”



    Friday, December 7, 2018 1:55 PM
  • Dear Mohamed, Thanks for your response.

    Our Infra team does not want to enable the default option.

    Cisco has got some feature enabled in their routers which is called as AutoQoS. So it this identifies Skype traffic and forwarding automatically.

    Is there any option to check this from client level if QoS/CoS is working as configured in the Cisco Prime?

    Monday, December 10, 2018 7:16 AM
  • Hi a2har,

    Based on my research, default is what unmarked traffic is classified as (using a null DSCP value) and is delivered on a best-effort bases just the same as all other non-prioritized traffic. You could refer to the following blog to find the details: Lync Quality of Service Behavior. It shows that One approach treats all media traffic as best effort (0), while another approach will provide a level of quality of service delivery, assuming that the network device is configured to prioritize DSCP 40 traffic (or any value desired).

    In addition, I find a blog about Validate QoS for Skype for Business Online you could refer to. 

    Note: This response contains a reference to a third party World Wide Web site. Microsoft can make no representation concerning the content of these sites. Microsoft is providing this information only as a convenience to you: this is to inform you that Microsoft has not tested any software or information found on these sites and therefore cannot make any representations regarding the quality, safety, or suitability of any software or information found there. There are inherent dangers in the use of any software found on the Internet, and Microsoft cautions you to make sure that you completely understand the risk before retrieving any software on the Internet.

    Best Regards,
    Evan Jiang


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.


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    Monday, December 10, 2018 8:02 AM
  • Try the below procedure and validate the QOS on Skype Hybrid:

    1. On Skype for business end - Speak on the microphone
    2. On the far-end (i.e. the PSTN) -  Speak on the microphone
    3. Click the Stop button on the top toolbar (on Microsoft Message Analyzer)
    4. Filter box - Remove all text and type RTP ->  press Enter -> click Apply.
    5. Filter only Real-Time Protocol (RTP) packets, the voice packets sent/received by Skype.
    6. Find a packet that has a source from Office365 (in this case 131.253.133.18) and single click to highlight it
    7. In the lower left pane of the window under Message Stack, click IPv4
    8. To the right, in the Details pane, click the line Differentiated Services to highlight it. (Note, you may need to expand the Name and Value columns)
    9. In the Value column of the Differentiated Services line, validate the DifferentiatedServicesField reads DSCP=46. Indicating the RTP packet coming from Office365, traversing your network to your PC using the port range 50,000-50,019 was tagged with Expedited Forwarding (EF) 46.

    This same procedure can be used to validate QoS markings for other Skype for Business traffic.

    • Proposed as answer by woshixiaobai Tuesday, December 11, 2018 7:10 AM
    Monday, December 10, 2018 8:11 AM
  • Hi a2har,

    Is there any update for this issue? If the reply is helpful to you, please try to mark it as an answer, it will help others who have the similar issue.

    Best Regards,
    Evan Jiang


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.


    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.

    Wednesday, December 12, 2018 7:05 AM