When using Sip trunking, hosted PBX or remote extensions, companies  need a router that not only can give VoIP priority over other non-real time traffic but also can slow down other connections to ensure crystal clear VoIP calls. Object based QoS, Traffic shaping, Bandwidth classification and limitation are some of the must have features in a modern router.

Draytek Vigor routers provide the ability to protect real time applications such as VoIP with enough bandwidth, minimized packet drop and delays.

Below is a guide to configure a traffic class for VoIP and allocate higher bandwidth ratio. Depending on the Vigor model you are configuring the configuration screens vary slightly.

1. Enable the QoS Control, choose Direction "Both" and type the bandwidth ratio that you'd like to reserve for SIP VoIP traffic.

2. SIP protocol (UDP:5060) is not defined in QoS Basic Configuration, therefore, we need to add a new Service Type via QoS Advanced Setup.

3. RTP (real-time transport protocol), which is used to provide end-to-end network transport functions suitable for applications transmitting real-time data, such as audio, video or simulation data, Also is not defined in QoS Basic Configuration, therefore, we need to add a new Service Type via QoS Advanced Setup.

4. Input Service Name, choose Service type and define the port numbers.

Please NOTE: UDP 10050 port to UDP 15000 port is the RTP port specified by Vigor, Other VoIP device may have it's own definition about RTP port.

5. Then we can select the new Service Type and activate the rule.

6. Check if SIP(UDP:5060) and RTP(UDP:10050~15000) is added in QoS Basic Configuration.

7. Now we can see the QoS bandwidth status in QoS Online Statistics.There is one more thing needed to be noticed - UDP port 5060 is only used for establishing connection, therefore, if we need to control full VoIP traffic, we need to add the real used ports(usually dynamic ports) into this class.

More Information on Draytek can be found in this other blogs.