3CX QoS

[HNR]

Hello

I have a MPLS network and users are using webclient and softphone to make and receive calls on PCs. I have some problems with voice quality and sometimes i have voice breaks. As you understand i don´t have voice vlan. My telco inform that i don´t have voice packet mark (dscp EF) between 3CX and his SBC. Can help me where i can see or to configure QoS on 3CX ?

Tks,
HNR

 

[Evolute IT]

Hello

I have a MPLS network and users are using webclient and softphone to make and receive calls on PCs. I have some problems with voice quality and sometimes i have voice breaks. As you understand i don´t have voice vlan. My telco inform that i don´t have voice packet mark (dscp EF) between 3CX and his SBC. Can help me where i can see or to configure QoS on 3CX ?

Tks,
HNR

If you use the softphones, the SBC is useless and QOS would be for WebRTC and RTP. Meaning HTTPS/443, and the RTP range (probably 9000-10999.)

 

[NickD_3CX]

3CX is a software that runs on an OS and utilizes the network interfaces provided by the OS.
The actual 3CX software for this reason cannot do any tagging like that, so whatever you need to do needs to be done on the OS level, or on the switches.

Generally though you need to be VERY careful when settings up QoS tagging because you can make things considerably worse if you are not careful.

 

[HNR]

Hi Nick_D,
Many thanks for your information, it was very important for me. I already have some experience with QoS on Cisco routers and Cisco Call Manager. I will follow this url: https://www.3cx.com/blog/voip-howto/qos-linux/

It is import because the customer has a MPLS network and i need to tag the leg between 3CX and Telco SBC.

I appreciate your support and if you have a suggest to implement QoS on 3CX please send me.

Tks,
HNR

 

[HNR]

Hi Nick_D,

As soon as possible could you say me which function this parameter on 3CX.

Parameter Settings > customer parameter (DSCP) > MSRTPTOS (This parameter instructs the Media Server to mark all the packets it generates with a value between 0 and 63 in the DSCP field in the IP Header. Default Value: 0 - Valid Values: 0-63)

I undestood that i have maket voice packets on network interfaces provided by the OS, but which value must put on MSRTPTOS (iten above) ?

Tks
HNR

 

[HNR]

Hi Nick_D,
As soon as possible could you say me which function this parameter on 3CX.
Parameter Settings > customer parameter (DSCP) > MSRTPTOS (This parameter instructs the Media Server to mark all the packets it generates with a value between 0 and 63 in the DSCP field in the IP Header. Default Value: 0 - Valid Values: 0-63)

I undestood that i have to mak voice packets on network interfaces provided by the OS, but which value must put on MSRTPTOS (iten above) ?

Tks
HNR

 

[NickD_3CX]

I believe this is referring to the Decimal value of each DSCP tag as explained here:
https://www.iana.org/assignments/dscp-registry/dscp-registry.xhtml

Again though, giving specific advice about QoS to someone else is very difficult as to decide these things, you need to be very intimate with the exact network layout.

Also keep in mind that some Operating Systems do not allow Applications to set the DSCP values and you must set them at the OS level or network level. I think Windows no longer allows Apps to set it, so keep this in mind.
I say this because I believe this custom parameter you found was implemented a long long time ago, back when 3CX was Windows-only, and Windows OS allowed apps to set this.