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Enable DSCP Marking in Windows OS (7, 8, 10)

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By default windows OS will set DSCP markings to '0' ignoring the marking settings on the client. This can be good and bad.

A good scenario is to make sure that torrent clients aren't getting priority (while ideally your enterprise network qos policies should overcome this problem as well)

A bad scenario is overriding DSCP markings from Jabber Client which marks packets genuinely  for seperating audio and video streams treatment.

While you can still overcome the problem of Jabber Client using network QoS policies, you can allow QoS marking on windows OS as follow:

1. Go to HKLM\System\CurrentControlSet\Services\Tcpip\QoS. If "QoS" folder doesn't exist there - create it.

2. Add a DWORD parameter named "Do not use NLA" and assign "1" as its value.

3. Reboot.

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Beginner

Hi,

i am using iperf to test QoS and i'm trying to set the DSCP values for the traffic i send between the two iperf Laptops. The solution above is not working for me. I checked if the registry entry still exists after the reboot. It does, but i still can't set the DSCP to the packets iperf is sending out.

Beginner

I have this value set as well but when performing a Wireshark capture, I'm seeing a value of 0.

Beginner

I have the same problem,

 

Does anyone know how to achieve it?

Beginner

When I did this, I was still getting a CS0 value on my outgoing packets.  

 

What I found that resolved the issue, however, was a group policy edit.

 

Each image caption has instructions for that step.

 

image.pngNotice the DSCP value of "CS0". We need this to be escalated for QoS.

 

image.pngOpen Local Group Policy Editor, then select Local Computer Policy > Computer Configuration > Windows Settings. Right click on Policy-based QoS and select Create new policy...

image.pngGive the policy a unique name, I went with Cisco Jabber QoS, and then assign a DSCP value. This is decimal value, so I input 26 which is AF31, which gives my Jabber the same QoS as my voice network with low drop probability. Then click next.

image.pngSelect "Only applications with the executable name:" and type in "CiscoJabber.exe". Then click next.

image.pngApply the policy to any source and destination IP address. And then click next.

image.pngChange "Select the protocol this QoS policy applies to" to TCP and UDP, since you need both marked, and allow from any source and destination port since there is a very wide range needed. Then click "Finish". Now test.

Assuming you have completed this, open wireshark and jabber and do a test call while capturing information.

 

Filter your packets by either RTP or SIP and then open a frame.  You should see your DSCP value, under the IP section, marked for AF31, as highlighted below.image.png

 

I ended up creating two separate policies to account for SIP and RTP individually as shown below:

image.png

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