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QOS for Softphones

Ejaz Ahmed

Hi Experts,

We have a small network having 6 to 10 users and single VLAN. All were using 3Cx soft phone in their machines. Users are complaining about the voice quality so we have upgraded our bandwidth and enabled QOS in the router. But still users experiencing the same issue. The router is managed by ISP. Apart from router we have a small unmanaged switch in our network. 

My doubt is how can we enable the QOS for softphones. In case of hardphones we ca create seperate vlan for voice and enable QOS in switch (managble switch). But this is not possible with softphones.

I would like to hear suggestions from you guys.

Thanks & Regards,


4 Replies 4



I remember similar case some years ago.

Cisco softphones (IP Communicator) were tagging the packets with DSCP=EF value.

But only in a case the Windows user running the application was having Admin rights assigned.

For users without Admin rights the packets were sent without any tagging.

Possibly 3Cx soft phone could also set the DSCP value?

Best regards,


Thank you Milan for the response.  I think 3CX application can tag the traffic,  I saw an article from their technical blogs. I wll try that and let u knw the result. 

Joseph W. Doherty
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Ideally, the application would tag your VoIP traffic.  Then your edge port would validate it (which requires the edge switch to be able to analyze the traffic).

If the application is unable to tag your VoIP traffic, then your edge port might be able to classify and tag it.  (This is a small step beyond what's needed for validation [which might need to remark].)

Once the VoIP traffic is tagged, special treatment is not automatic.  You would need to work that out with your ISP (or more involved, have a device before the ISP device that can fully manage your traffic before it's forwarded to the ISP device - including shaping for ISP bandwidth so that the ISP will never see congestion).

Thank you so much for the response Joseph... :) 

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