Skip to content
MikroTik RouterOS Docs

Burst Settings

Burst Settings

Section titled “Burst Settings”

Burst lets a queue temporarily exceed its normal rate limit to handle short traffic spikes — page loads, file download starts, DNS lookups — without inflating the steady-state cap. Once sustained traffic fills the burst budget, the queue drops back to its configured rate.

Burst is available on both Simple Queue and Queue Tree entries.

Parameters

Section titled “Parameters”
ParameterDescription
burst-limitMaximum rate allowed during burst. Must be higher than max-limit.
burst-thresholdBurst activates while the measured average rate is below this value; deactivates when the average rises above it.
burst-timeLength of the averaging window in seconds (not the burst duration). RouterOS computes the average rate over this window to decide whether burst is active.

How burst works

Section titled “How burst works”

RouterOS continuously measures the average throughput over the burst-time window:

  1. Average below threshold → burst is active; traffic may reach burst-limit.
  2. Average reaches threshold → burst deactivates; traffic is capped at max-limit.
  3. Average falls back below threshold → burst reactivates.

Because the window is a sliding average, a client that sends at burst-limit will push its average up to burst-threshold in roughly:

burst_duration ≈ burst-time × (burst-threshold / burst-limit)

For example, with burst-time=8s, burst-limit=40M, burst-threshold=20M:

  • burst_duration ≈ 8 × (20 / 40) = 4 seconds

After 4 seconds at 40 Mbps, the 8-second average reaches 20 Mbps (threshold) and burst shuts off.

Parameter relationships

Section titled “Parameter relationships”
limit-at (guaranteed) ≤ max-limit (steady-state cap) < burst-limit (burst peak)
                                         ↑
                              burst-threshold sits here
                              (between max-limit and burst-limit)

Rule of thumb: Set burst-threshold between max-limit and burst-limit. If threshold equals or exceeds burst-limit, burst is always active. If threshold equals or falls below max-limit, burst never activates.

Simple Queue burst

Section titled “Simple Queue burst”

In Simple Queue, burst applies independently to the upload and download directions.

/queue simple
add name=client-10 \
    target=192.168.1.10/32 \
    max-limit=20M/10M \
    burst-limit=60M/30M \
    burst-threshold=30M/15M \
    burst-time=8s/8s

This gives client 192.168.1.10:

  • Download: up to 60 Mbps for ~2.7 seconds, then settles at 20 Mbps.
  • Upload: up to 30 Mbps for ~4 seconds, then settles at 10 Mbps.

Burst with limit-at in Simple Queue

Section titled “Burst with limit-at in Simple Queue”

When limit-at is set, it acts as a guaranteed floor. Burst still applies against max-limit:

/queue simple
add name=client-vip \
    target=192.168.1.20/32 \
    limit-at=5M/2M \
    max-limit=20M/10M \
    burst-limit=50M/25M \
    burst-threshold=30M/15M \
    burst-time=10s/10s

Queue Tree burst

Section titled “Queue Tree burst”

In Queue Tree, burst is configured per queue entry. Burst interacts with limit-at (guaranteed rate) and max-limit (ceiling).

/queue tree
add name=web-class \
    parent=WAN \
    packet-mark=pm-http \
    limit-at=5M \
    max-limit=50M \
    burst-limit=100M \
    burst-threshold=30M \
    burst-time=8s

Web traffic is guaranteed 5 Mbps, capped at 50 Mbps during sustained use, and can burst to 100 Mbps for approximately 2.4 seconds when the link is underutilised.

Verification

Section titled “Verification”

Check whether burst is currently active and measure the average rate:

/queue simple print stats
/queue tree print stats

The rate column shows current throughput. The queued-bytes and queued-packets values indicate whether the queue is building a backlog.

Common mistakes

Section titled “Common mistakes”

Burst threshold equal to or above burst-limit — burst is permanently active:

# WRONG — burst never deactivates
burst-limit=40M burst-threshold=40M

Burst threshold below max-limit — burst never activates:

# WRONG — average always exceeds threshold immediately
max-limit=20M burst-limit=40M burst-threshold=15M

Very long burst-time with low burst-threshold — the averaging window is too generous; burst stays active for too long and the rate is effectively always at burst-limit:

# Probably not what you want for a 100 Mbps ISP link
burst-time=60s burst-limit=100M burst-threshold=10M

Forgetting to set burst-limit higher than max-limit — RouterOS ignores burst if burst-limit ≤ max-limit.

Section titled “Related”