All MX appliances have traffic shaping capabilities.
If you are fully tunneling to a DC MX then you can have two way QoS but if your transport for your voice call manager is the internet then you will only get outbound QoS.
On the security & SD-WAN -> traffic shaping page you can set these options.
Step1: Make sure your upstream and downstream bandwidth is set to the correct maximum values as your circuit speeds.
Step2: Make sure you match your voice traffic either through L7 application matching or through L3/4 IPs and ports. And give it a DSCP value of EF(expedite forwarding). You can set the queue to high but it should take the real-time queue by setting your DSCP value to EF.
Step3: Match some other traffic types and give them high/medium/low queuing service.
The logic is as follows.
- Each WAN interface on an MX has 4 queues
- The realtime queue is a strict priority queue (the moment 1 packet is waiting in that queue it gets serviced first)
- The other 3 queues are weighted bandwidth queues where high gets 4/7 of the maximum bandwidth, medium gets 2/7 and low gets 1/7.
So imagine you have a circuit with 70 Mbps upstream:
High would get 40 Mbps, medium 20 Mbps, low 10 Mbps. However if one packet enters the realtime queues the other queues stops servicing and the realtime queue is emptied first.
