QoS on Windows – An Example

If you do need QoS, this step by step guide shows how to create a policy in Windows 2008 or 2012 that tags all traffic from the machine with a higher QoS so as to ensure traffic is given priority.

Step 1: Create a Local Policy for QoS

QoS - Create new policy

  • Run “gpedit.msc
  • Go to the “Local Computer Policy -> Computer Configuration -> Windows Settings” node
  • Right-click on “Policy-based QoS” and click on “Create new policy …

QoS - Create Policy name

  • Set the “Policy Name” to “All Traffic
  • Set the “DSCP Value” to 56, Click the “Next >” button

QoS - Policy for applications

  • Select the “All Application” radio button, click the “Next >

QoS - Policy applies to

  • Select the “Any source IP address” radio button
  • Select the “Any destination IP address” radio button, click the “Next >” button

QoS - Policy Protocols

  • Set the “Select the protocol this QoS policy applies to” field to “TCP and UDP
  • Select the “From any source port” radio button
  • Select the “To any destination port” radio button
  • Click the “Finish

Step 2: Apply the New Policy Immediately

QoS - Execution file cmd

  • Run “gpupdate.exe”

Step 3: Checking QoS is Applied to Outgoing Traffic

Running Wireshark will allow you to check that outgoing traffic is indeed being tagged with the correct DSCP value.

QoS - Wireshark

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  1. Ronald

    this is exelent advise thanks 3cx team. 3cx is just getting better and better. This why we choose 3cx. Just one question does this mean we don’t need 3rd party people to do qos for us anymore with mikrotik routers we know nothing about.

    November 3, 2016 at 11:50 am Reply
    • Keep in mind Ronald that this simply tags the packets leaving your installation. You will still have to prioritize traffic in switches and routers. The Mikrotik that you mentioned does a great job of traffic shaping and traffic prioritization and can recognize the DSCP values set in the steps above or can set the DSCP values based on just about any criteria and then prioritize them.

      Also not that in this example, all traffic from this server is marked with the same priority. This means that if you do large transfers to your 3CX instance (downloading call recordings etc,) that traffic will carry the same priority as RTP and SIP traffic and may cause brief contention.

      November 10, 2016 at 2:24 pm
  2. Complex1

    Is this policy setting also useful if 3CX is running on a Windows 10 Pro Server?

    November 3, 2016 at 1:08 pm Reply
  3. It’s great to find somoene so on the ball

    November 12, 2016 at 4:19 am Reply