To configure QoS for an interface, proceed as follows:
Click the Edit button of the respective interface.
The Edit Interface dialog box opens.
Make the following settings:
Downlink Mbit/sec/Uplink Mbit/sec: Enter the uplink and downlink bandwidth (in Mbit/s) provided by your ISP. For example, for a 5 Mbit/s Internet connection for both uplink and downlink, enter 5.
Note – Enter the uplink and downlink bandwidth in Mbit/s - even if an error message assumes Kbit/s (which is displayed if the entered value is invalid).
If you have a fluctuating bandwidth, enter the lowest value that is guaranteed by your ISP. For example, if you have a 5 Mbit/s Internet connection for both uplink and downlink with a variation of 0.8 Mbit/s, enter 4.3 Mbit/s. Note that if the available bandwidth becomes temporarily higher than the configured lowest guaranteed value, the gateway can make a projection taking the new bandwidth into account, so that the percentage bandwidth for the priority traffic will be increased as well; unfortunately, this does not work vice versa.
Limit uplink: Selecting this option tells the QoS function to use the configured downlink and uplink bandwidth as the calculation base for prioritizing traffic that passes this interface. The Limit uplink option is selected by default and should be used for the following interface types:
- Ethernet interface (with a router sitting in between the gateway and the Internet—the bandwidth provided by the router is known)
- Ethernet VLAN interface (with a router sitting in between the gateway and the Internet—the bandwidth provided by the router is known)
- DSL (PPPoE)
- DSL (PPPoA/PPTP)
- Modem (PPP)
Unselect the Limit uplink checkbox for these interfaces whose traffic shaping calculation base can be determined by the maximum speed of the interface. However, this only applies to the following interface types:
- Ethernet interface (directly connected to the Internet)
- Ethernet VLAN interface (directly connected to the Internet)
For interfaces with no specific uplink limit given, the QoS function shapes the entire traffic proportionally. For example, if you have configured 512 Kbit/s for VoIP traffic on a Ethernet DHCP interface and the available bandwidth has decreased by half, then 256 Kbit/s would be used for this traffic (note that proportional shaping works in both directions in contrast to interfaces that rely on a fix maximum limit).
Limit Downlink: If enabled, Stochastic Fairness Queuing (SFQ) and Random Early Detection (RED) queuing algorithms will avoid network congestion. In case the configured downlink speed is reached, packets from the most downlink consuming stream will be dropped.
Upload optimizer: If enabled, this option will automatically prioritize outgoing TCP connection establishments (TCP packets with SYN flag set), acknowledgment packets of TCP connections (TCP packets with ACK flag set and a packet length between 40 and 60 bytes) and DNS lookups (UDP packets on port 53).
Your settings will be saved.
Enable QoS for the interface.
Click the toggle switch of the interface.
The toggle switch turns green.