QoS#
Network → QoS shapes traffic per interface: an upload rate for what the router sends out of the interface, and a download rate for what arrives on it. Shaping at a rate a little below what the line really delivers keeps the queue on the router, where CAKE keeps it short and fair, instead of in the modem, where it adds latency to everything.
The page#
One row per shaped interface.
| Column | What it shows |
|---|---|
| Interface | The interface, with its description |
| Upload | The upload rate, Off, or the name of a policy this page does not edit |
| Download | The download rate — "policed" when it is a limiter — or Off |
| Status | Active when the router is running the queue the configuration asks for; Not applied when it is not (hover for the reason); a dash when the agent cannot read the kernel from where it runs |
| Shaped traffic | The bytes that have gone through each direction's shaper |
A VLAN is a row like any other interface. Unused policies lists shaping policies that nothing is attached to, each with a Delete button.
With nothing shaped, the page says so and offers Add shaping.
Adding or editing shaping#
Add shaping asks for the interface; clicking a row opens the same editor for that interface. Each direction has a switch and, when it is on, these fields:
| Field | What it sets |
|---|---|
| Rate (Mbit/s) | The shaping rate. Decimals are allowed; a percentage of the link speed, such as 95%, is accepted too |
| Flow isolation | What CAKE shares fairly between: sending hosts then flows, receiving hosts then flows, hosts and flows (the router's default), host pairs, single hosts, flows, or none |
| NAT-aware fairness | Tells apart the hosts behind the router's NAT, so a flow isolation by host counts each of them |
| ACK filtering | Drops redundant TCP acknowledgements; most useful on the narrow direction of an asymmetric line |
| GSO splitting | Splits large offloaded packets into their segments; on by default |
| Round-trip time (ms) | The path's typical round trip; empty is the router's default, 100 ms |
Download has a Method: CAKE shaping queues what is over the rate, Policing
drops it. Policing takes a rate and a Burst (bytes, such as 15k).
New shaping starts with the settings a WAN usually wants: sending hosts then flows, NAT-aware and with ACK filtering for upload; receiving hosts then flows and NAT-aware for download. Only the rates are yours to fill in.
A rate the router would refuse is shown under its field and Save changes stays off until it is fixed. Saving adds the change to the pending changes; the Commit Bar applies it.
Remove shaping asks once more, then takes both directions off the interface.
What saving changes#
The router shapes upload with a CAKE policy on the interface. It cannot put CAKE on an interface's incoming traffic directly, so CAKE download shaping moves that traffic through a device made for the purpose and shapes it there. The page never shows the device: it is the interface's download, and the agent's planner chooses, reuses and releases it.
What the planner does when you save:
- A policy only this interface uses is edited in place. A policy shared with another interface is left to it, and this interface gets one of its own; the pending changes say so.
- A policy nothing uses any more is deleted. When the last shaping on the router goes, the QoS configuration goes with it.
- The download device is kept and reused. Turning CAKE download shaping off detaches its policy and stops redirecting the interface's traffic to it; the device stays, idle, and the next download shaping on any interface uses it again. Deleting the device through the router's configuration API is a change that has stopped that API before, so nothing in the product does it, and nothing needs it.
- A VLAN is shaped as itself and its download is redirected at the VLAN, not at its parent. A VLAN inside another VLAN cannot be shaped on this platform.
In Advanced mode the pending changes show the commands, and the page's CLI view shows the QoS configuration as the router holds it.
What the page does not do#
The page never measures your line. The rate is the number you enter; run a speed test with nothing else using the line and shape at 90 to 95 per cent of what it shows.
Integration offers on this page#
If an installed app declares a hint for the qos page it appears as a card under the
header. See Apps — integration offers.
See also#
- Shape a link with CAKE — the task, step by step.
- Uplinks (multi-WAN) — which interface carries traffic, and therefore which one is worth shaping.
- Interfaces — the interfaces and VLANs shaping is attached to.
- The interface panel — the queue discipline the kernel is running on an interface, in Advanced mode.