QoS implementation

[DBOD]

I am running V11 on a Windows 7 machine.

I just put in a new Netgear router (UTM5) and I am setting up the QoS profiles. The router comes with no defined QOS profiles. I noticed that my Aastra phones already mark the RTP and SIP packets with defaults of 46 and 26 for the DSCP service. Wireshark shows the differentiated services field for all SIP and RTP packets originating from the 3CX PBX is zero. Now I don't care about the data between the PBX and the phones. But it seems odd that the phone sends the information to the 3CX PBX and the 3CX PBX remarks it to zero before sending it onto the UTM5 router. I know I can and have remarked them in the router. Wouldn't it be better if the default for 3CX was not to remark them? Or have 3CX mark zero fields to some non-zero industry standard for voip? Is this just a quirk of my system configuration? Did I miss something in the configuration of the 3CX software? Thank you.

 

[nickjhunt]

I have got a Netgear UTM5 and I am running QOS based on traffic port and type. I would imagine the traffic coming out of the server to be subjected to policy rules regarding QOS so you can set up a policy that marks traffic from certain applications with the relevant DSCP value to fit your network QOS policy. I have got it setup on my laptop for running the softphone and I can see all of the traffic marked with the assigned value (46).

 

[DBOD]

I know how the UTM5 can mark the packets. I can see RTP packets with the DSCP set coming from the router. By the time the 3CX PBX sends it to the SIP phone it is unmarked. Not a big deal since it is on the last leg of it's journey. In the other direction, the SIP phone sends marked packets to the 3CX PBX and the 3CX PBX sends them on to the UTM5 unmarked. Now I don't know if 3CX is unmarking them or if Windows is doing it. My point is that I should not have to remark them in the router. Seems odd to me.

 

[cpontus]

I set up QoS on my 3CX server by following this and substituting the appropriate values. I also limited it to any of the 3CX applications and not traffic from the entire machine.

http://www.3cx.com/blog/voip-howto/qos-windows-2008-server-local-policy/

 

[DBOD]

That is useful information. The example shows how to implement it at the machine level. It looks like the option exists to implement it at the application level also. 3CX has 9 processes running on my Windows 7 machine. Does anyone know which processes are responsible for moving the sip and rtp packets? I also discovered that you can change the priority of the processes in the Windows Task Manager by right clicking on the individual process. My machine looks like it has most processes priorities set to "Normal". I have a second issue with performance of my system. My 3CX PBX doubles as my desktop in the office. Go ahead and laugh. But this is a small office and I am bandwidth limited on the internet connection. So when my machine gets busy doing other tasks, the sound quality gets choppy. Has anyone experimented with changing the 3CX process priorities to improve quality? Thanks.

 

[nickjhunt]

If you look in the services on the PBX you can show the process associated with each 3CX service. You can then associate this process with QOS in the local group policy. mark it as 46 and it will be priority traffic. NOTE: rest of the network needs to be running DSCP Qos to read these bits. You can also enforce DSCP on port ranges so 5000, 9000-9049 get marked for Priority.