MikroTik burst explained with a worked example
Last updated: 2 October 2026
Burst lets a customer go faster than their plan for a short while, so pages open quickly, and then settles back to the normal speed for long downloads. It has four settings, and one of them, burst-time, does not mean what most people expect.
The four settings
| Setting | Meaning |
|---|---|
max-limit | The normal speed: what the customer gets when burst is not allowed. |
burst-limit | The higher speed allowed during a burst. |
burst-threshold | Burst is allowed while the customer's average speed is below this figure, and switched off once the average goes above it. |
burst-time | The period the average is measured over. It is not the length of the burst. |
For burst to make sense: burst-threshold ≤ max-limit < burst-limit.
How the router decides
The router keeps an average of the customer's speed over the last burst-time seconds. While that average is under the threshold, the customer may use up to burst-limit. As soon as the average passes the threshold, the customer is held to max-limit. When they slow down and the average falls under the threshold again, burst is back.
A worked example
Download settings: max-limit 5M, burst-limit 10M, burst-threshold 4M, burst-time 16 seconds. The customer has been idle and starts a large download.
| Second | Speed | Average over the last 16 s | Burst |
|---|---|---|---|
| 0 | 0 | 0 | allowed |
| 2 | 10 Mbps | 1.25 Mbps | allowed |
| 4 | 10 Mbps | 2.5 Mbps | allowed |
| 6 | 10 Mbps | 3.75 Mbps | allowed |
| about 6.4 | 10 Mbps | 4 Mbps | stops |
| after that | 5 Mbps | rises towards 5 Mbps | off |
The burst lasted about 6.4 seconds, not 16. While the download continues at 5 Mbps the average stays above 4 Mbps, so there is no second burst until the customer pauses long enough for the average to drop under the threshold.
How long does a burst last?
From idle, at full burst speed:
burst length = burst-time x burst-threshold / burst-limit
16 s x 4M / 10M = 6.4 secondsSo you lengthen the burst by raising burst-time or burst-threshold, and shorten it by raising burst-limit. The router measures the average in steps, so real figures are close to this, not exact.
In a simple queue
/queue simple add name=ali target=192.168.88.10/32 max-limit=2M/5M burst-limit=4M/10M burst-threshold=1500k/4M burst-time=16s/16sEvery pair is upload/download for the target, the same order as max-limit. Queues in general are covered in bandwidth limit per user.
In a rate-limit
Hotspot user profiles, PPP profiles and RADIUS take the same four parts in one line, in this order: speed, burst speed, burst threshold, burst time.
/ppp profile set [find name=5M] rate-limit="2M/5M 4M/10M 1500k/4M 16/16"
/ip hotspot user profile set [find name=5M] rate-limit="2M/5M 4M/10M 1500k/4M 16/16"Here the burst time is written in seconds without a unit. The quotes are needed because of the spaces. See PPPoE speed limits with profiles and hotspot user profiles.
Choosing sensible values
- Set the threshold at about three quarters of max-limit. If the threshold equals max-limit, a customer downloading at full normal speed sits right on the edge and burst behaves unevenly.
- Burst speed of up to twice the plan is common. Every customer can burst at once after a power cut, so do not promise more than the line can carry.
- Speed test websites run for only a few seconds. With a long burst they show the burst speed, not the plan, and customers will quote that number back to you.
- No burst at all? Then FastTrack may be skipping the queue: see queues not working.
Where RadiusNest fits
In RadiusNest burst is an optional part of a package next to its normal speed. The values are sent to the router at each login, and the router applies them exactly as it would from a profile. RadiusNest does not change how burst behaves; the rules on this page are the router's.
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Questions and answers
Is burst-time the length of the burst?
No. It is the period over which the average speed is measured. The burst itself is shorter: burst-time times threshold divided by burst-limit.
Why does my customer never get a second burst?
While they keep downloading at the normal speed, their average stays above the threshold. Burst returns after they have been slow or idle for a while.
What happens if burst-threshold is higher than max-limit?
The average can never climb above the threshold at normal speed, so the queue does not settle into a clean burst and rest pattern. Keep the threshold at or below max-limit.