Traffic Shaping with MikroTik: Ensuring Smooth Network Performance
Traffic shaping helps routers control bandwidth use, reduce latency, and keep critical applications like VoIP and video stable. This guide gives you step-by-step instructions with real MikroTik RouterOS v7 configurations.
Why Traffic Shaping Matters
- Keep latency low during heavy load.
- Prioritize voice, video, and interactive apps.
- Share bandwidth fairly across users and VLANs.
- Prevent bufferbloat that ruins real-time traffic.
Core Concepts & Terminology
- Simple Queues: Quick limits per IP/subnet.
- Queue Tree (HTB): Hierarchical classes for complex policies.
- PCQ: Per-connection fairness for many hosts.
- CAKE: Modern shaper with flow isolation, fairness, and DiffServ support.
- Packet Marking: Classify packets for queue assignment.
- CIR vs MIR: Guaranteed vs maximum bandwidth.
Packet Flow, FastTrack, and Bridge Notes
- Simple Queues and Queue Tree usually run in postrouting.
- FastTrack bypasses queues — exclude or disable it for shaped flows.
- For bridged traffic, enable
use-ip-firewall=yesto make queues see the packets.
How to Set the Correct Shaping Rate
- Run a wired speed test during peak hours.
- Set shaping at ~95% of actual throughput (both up and down).
- On variable links (LTE, DSL), use CAKE autorate or scripts to adapt rates.
Choosing the Right Strategy
- One WAN, mixed users: Use CAKE in a simple queue.
- Many users/VLANs: Use PCQ with Queue Tree for fairness.
- Voice/Video critical: Use DSCP-aware shaping.
1: CAKE Simple Queue Config Example
/queue type
add name=cake-300-50 kind=cake cake-bandwidth=300M cake-diffserv=diffserv4 cake-flowmode=triple-isolate
/queue simple
add name=wan-cake queue=cake-300-50 max-limit=300M/50M target=ether1
2: PCQ + Queue Tree Config Example
/ip firewall mangle
add chain=prerouting in-interface=ether1 action=mark-packet new-packet-mark=download passthrough=no
add chain=postrouting out-interface=ether1 action=mark-packet new-packet-mark=upload passthrough=no
/queue type
add name=pcq-down kind=pcq pcq-classifier=dst-address
add name=pcq-up kind=pcq pcq-classifier=src-address
/queue tree
add name=down parent=global packet-mark=download queue=pcq-down max-limit=200M
add name=up parent=global packet-mark=upload queue=pcq-up max-limit=40M
3: DSCP-Aware Shaping Config Example
/ip firewall mangle
add chain=prerouting in-interface=ether1 dscp=46 action=mark-packet new-packet-mark=voip-down passthrough=no
add chain=postrouting out-interface=ether1 dscp=46 action=mark-packet new-packet-mark=voip-up passthrough=no
/queue type
add name=pcq-voip kind=pcq pcq-classifier=dst-address
add name=pcq-best kind=pcq pcq-classifier=dst-address
/queue tree
add name=down-voip parent=global packet-mark=voip-down queue=pcq-voip limit-at=10M max-limit=30M priority=1
add name=down-best parent=global packet-mark=download queue=pcq-best limit-at=20M max-limit=70M priority=8
FastTrack and QoS
- FastTrack skips queues.
- Exclude shaped traffic from FastTrack.
- Disable FastTrack during testing.
Verification & Monitoring
/queue simple print stats– check queue counters./tool ping 1.1.1.1 interval=0.2 count=50– measure latency under load./tool torch interface=ether1– watch flows./ip firewall mangle print stats– confirm marks.
Troubleshooting Checklist
- FastTrack active? Check filter counters.
- No packet marks? Verify chain/interface.
- Bridge traffic unseen? Enable the firewall on the bridge.
- Wrong parent in Queue Tree? Use
globalfor total pipe. - Set the bandwidth too high? Lower to ~95% real speed.
Reusable Snippets
Per-IP Simple Queues from Address List
:foreach A in=[/ip firewall address-list find where list="qos-clients"] do={
:local ip [/ip firewall address-list get $A address]
/queue simple add name=("sq-" . $ip) target=$ip max-limit=25M/5M queue=cake-25M
}
FAQ
-
- Where to set CAKE bandwidth? In the queue type and in the simple queue max-limit.
- Which diffserv mode? Use 3-class or 4-class, depending on needs.
- Can I keep FastTrack? Yes, but exclude shaped flows.
Check our list of MikroTik guides.
