Here is how I have QoS for my VoIP adapter.
1) Make sure you set proper Egress Bandwidth on your WAN interface. Without this nothing will function properly.
Ingress is ignored .... reserved for future use as per built-in help.
2) Configure BWM. If your app is capable to set DSCP (like my Cisco ATA is) then just use the value, otherwise you can use source or destination IP and/or port.
I have 25/10 Mbps WAN connection.
My basic example on the picture, I only prioritize VoIP, everything else is on same level.
In addition I'm also configuring the QoS on the switch for the port 5 where the ATA is connected to the highest priority (not that this is all needed on my gigabit almost zero utilized network
Cisco SPA112 settings.
I'm worried about RTP only. DiffServ 0xb8 is same as DSCP 46 (google the conversion .. it's first six bits from the left)