Traffic Generator

Traffic Generator

Version Info

RouterOS 7.16 | Min: v6.0+ | 15 minutes | Advanced

Tested on: 7.16 7.14

Version-specific notes

• v7.21: PCAPNG injection support added (inject-pcap command)
• v7.0: Same functionality as v6; menu path unchanged
• v6.0: Traffic Generator tool introduced

TL;DR (Quick Start)

For the impatient: generate test traffic through a device under test.

Configure port and run quick test:

/tool/traffic-generator/port/add interface=ether1 name=port0
/tool/traffic-generator/quick interface=ether1 mbps=100 packet-size=1400

Overview

What this does: Traffic Generator creates and sends raw packets over network interfaces to evaluate Device Under Test (DUT) or System Under Test (SUT) performance. Unlike Bandwidth Test which measures point-to-point throughput, Traffic Generator creates customizable packets that traverse network paths and return for comprehensive metrics collection including latency distribution, jitter, packet loss, and out-of-order detection.

When to use this:

• Test router/firewall throughput capacity
• Measure latency and jitter through network paths
• Stress test network equipment before deployment
• Validate QoS configurations under load
• Test IPsec/VPN tunnel performance
• Evaluate switch fabric performance
• Detect packet loss and out-of-order issues

Prerequisites:

• RouterOS 6.0 or newer
• Traffic Generator feature enabled in device-mode
• Two or more interfaces for proper testing
• Understanding of network topology and routing

How it differs from Bandwidth Test:

• Generates raw packets with full control over headers
• Measures latency distribution, not just throughput
• Detects out-of-order packets
• Supports multiple streams with different configurations
• Packets can traverse complex paths (routed, tunneled, switched)
• Uses FastPath automatically when available

Security Restriction

Traffic Generator can be permanently disabled via /system/device-mode/update traffic-gen=no (requires physical reset button press). This prevents misuse for network attacks. Once disabled, re-enabling requires factory reset.

Packet Capture Limitation

Packets generated by Traffic Generator cannot be captured using packet sniffer, torch, or firewall rules on the outgoing interface of the generating router. This is by design.

Core Concepts

Architecture

Traffic Generator uses three main components:

1. Ports - Associate interfaces with TX/RX operations
2. Packet Templates - Define packet structure (headers, IPs, ports)
3. Streams - Configure traffic flows with rate limits

┌──────────────┐     ┌──────────────┐     ┌──────────────┐
│    PORTS     │────▶│  TEMPLATES   │────▶│   STREAMS    │
│              │     │              │     │              │
│ interface    │     │ headers      │     │ rate (mbps)  │
│ assignment   │     │ src/dst IP   │     │ packet size  │
│              │     │ src/dst port │     │ template ref │
└──────────────┘     └──────────────┘     └──────────────┘

Quick Mode vs Persistent Mode

Quick mode: Single command that starts, runs, and displays results interactively. Best for ad-hoc testing.

/tool/traffic-generator/quick interface=ether1 mbps=100

Persistent mode: Configure components separately, start/stop as needed, statistics stored for later analysis.

/tool/traffic-generator/start
# ... test runs in background ...
/tool/traffic-generator/stop

Port Configuration

Associate interfaces with Traffic Generator before creating templates.

Add a Port

/tool/traffic-generator/port/add interface=ether1 name=port0

View Ports

/tool/traffic-generator/port/print

Expected output:

Flags: X - DISABLED; D - DYNAMIC; I - INACTIVE
Columns: NAME, INTERFACE, FIRST-HEADER
#   NAME   INTERFACE  FIRST-HEADER
0   port0  ether1     mac

Disable a Port

/tool/traffic-generator/port/set port0 disabled=yes

Packet Template Configuration

Define what packets look like using templates. Each template specifies headers, addresses, and payload.

Basic Template

Create a template for routed traffic:

/tool/traffic-generator/packet-template/add \
    name=test-template \
    header-stack=mac,ip,udp \
    ip-src=192.168.1.100/32 \
    ip-dst=10.0.0.100/32 \
    ip-gateway=192.168.1.1 \
    udp-src-port=12345 \
    udp-dst-port=54321 \
    port=port0

Template with VLAN Tag

/tool/traffic-generator/packet-template/add \
    name=vlan-template \
    header-stack=mac,vlan,ip,udp \
    vlan-id=100 \
    ip-src=192.168.1.100/32 \
    ip-dst=10.0.0.100/32 \
    ip-gateway=192.168.1.1 \
    port=port0

View Templates

/tool/traffic-generator/packet-template/print

Update Assumed MACs

When network topology changes, update automatically determined values:

/tool/traffic-generator/packet-template/set [find]

Running set without parameters triggers MAC address re-resolution.

Stream Configuration

Streams define traffic flows: which template to use, at what rate, and with what packet size.

Create a Stream

/tool/traffic-generator/stream/add \
    name=stream1 \
    num=0 \
    port=port0 \
    tx-template=test-template \
    mbps=500 \
    packet-size=1400

Stream ID Requirement

Each stream must have a unique num value (0-15). This identifier tracks packets for statistics collection.

Variable Packet Size

Test with random packet sizes in a range:

/tool/traffic-generator/stream/add \
    name=variable-stream \
    num=1 \
    port=port0 \
    tx-template=test-template \
    mbps=100 \
    packet-size=64-1500

View Streams

/tool/traffic-generator/stream/print

Running Tests

Quick Mode Test

Run an immediate test with inline parameters:

/tool/traffic-generator/quick interface=ether1 mbps=100 packet-size=1400 duration=30s

Output displays real-time statistics until the test completes.

Start Persistent Test

/tool/traffic-generator/start

Stop Test

/tool/traffic-generator/stop

Check Running Status

/tool/traffic-generator/print

Example output:

             latency-distribution-max: 100us
               measure-out-of-order: no
              stats-samples-to-keep: 100
                            test-id: 0
  latency-distribution-measure-interval: 1ms600us
       latency-distribution-samples: 16
                            running: yes

Statistics Collection

When not using quick mode, statistics are stored for analysis.

View Stream Statistics

/tool/traffic-generator/stats/stream/print

Example output:

SEQ  NUM  TX-PACKET   TX-RATE   RX-PACKET   RX-RATE   LOST-PACKET  LOST-RATE
  0    0    1000000   500Mbps     999998   499.9Mbps           2      0.0002%
TOT    0    1000000   500Mbps     999998   499.9Mbps           2      0.0002%

View Latency Distribution

/tool/traffic-generator/stats/latency-distribution/print

Example output:

# LATENCY         COUNT     SHARE GRAPH
0 0-15.5us            0        0%
1 15.5us-31us      1234     12.3% ************
2 31us-46.5us      5678     56.8% ********************************************************
3 46.5us-62us      2345     23.5% ***********************
4 62us-77.5us       743      7.4% *******

View Port Statistics

/tool/traffic-generator/stats/port/print

Clear Statistics

/tool/traffic-generator/stats/stream/reset

Common Scenarios

Scenario: Test Router Forwarding Performance

Set up two-port traffic flow to test packet forwarding:

Topology:

[Traffic Gen] ether1 ───▶ [DUT] ───▶ ether2 [Traffic Gen]

Configuration:

# Create ports
/tool/traffic-generator/port/add interface=ether1 name=port0
/tool/traffic-generator/port/add interface=ether2 name=port1

# Create templates (traffic flows both directions)
/tool/traffic-generator/packet-template/add \
    name=to-dut \
    header-stack=mac,ip,udp \
    ip-src=192.168.1.100/32 \
    ip-dst=192.168.2.100/32 \
    ip-gateway=192.168.1.1 \
    port=port0

/tool/traffic-generator/packet-template/add \
    name=from-dut \
    header-stack=mac,ip,udp \
    ip-src=192.168.2.100/32 \
    ip-dst=192.168.1.100/32 \
    ip-gateway=192.168.2.1 \
    port=port1

# Create bidirectional streams
/tool/traffic-generator/stream/add name=outbound num=0 port=port0 \
    tx-template=to-dut mbps=500 packet-size=1400
/tool/traffic-generator/stream/add name=inbound num=1 port=port1 \
    tx-template=from-dut mbps=500 packet-size=1400

# Run test
/tool/traffic-generator/quick duration=60s

Scenario: Test IPsec Tunnel Performance

Measure throughput through an encrypted tunnel.

R1 (Gateway 1):

/ip/address/add address=192.168.33.1/30 interface=ether1
/ip/address/add address=1.1.1.2/24 interface=ether2

/ip/ipsec/peer/add address=192.168.33.2 secret=mypassword
/ip/ipsec/policy/add sa-src-address=192.168.33.1 sa-dst-address=192.168.33.2 \
    src-address=1.1.1.0/24 dst-address=2.2.2.0/24 tunnel=yes

R2 (Gateway 2):

/ip/address/add address=192.168.33.2/30 interface=ether1
/ip/address/add address=2.2.2.2/24 interface=ether2

/ip/ipsec/peer/add address=192.168.33.1 secret=mypassword
/ip/ipsec/policy/add sa-src-address=192.168.33.2 sa-dst-address=192.168.33.1 \
    src-address=2.2.2.0/24 dst-address=1.1.1.0/24 tunnel=yes

Traffic Generator (connected to both gateway internal interfaces):

/tool/traffic-generator/port/add interface=ether2 name=port0
/tool/traffic-generator/port/add interface=ether3 name=port1

/tool/traffic-generator/packet-template/add \
    header-stack=mac,ip,udp \
    ip-dst=2.2.2.1/32 ip-gateway=1.1.1.2 ip-src=1.1.1.1/32 \
    name=tunnel-out port=port0

/tool/traffic-generator/packet-template/add \
    header-stack=mac,ip,udp \
    ip-dst=1.1.1.1/32 ip-gateway=2.2.2.2 ip-src=2.2.2.1/32 \
    name=tunnel-in port=port1

/tool/traffic-generator/stream/add name=encrypted-out num=0 \
    port=port0 tx-template=tunnel-out mbps=450 packet-size=1450
/tool/traffic-generator/stream/add name=encrypted-in num=1 \
    port=port1 tx-template=tunnel-in mbps=450 packet-size=1450

/tool/traffic-generator/quick duration=30s

Scenario: Latency Measurement

Test network latency with small packets at low rate:

/tool/traffic-generator/set latency-distribution-max=1ms measure-out-of-order=yes
/tool/traffic-generator/quick interface=ether1 pps=1000 packet-size=64 duration=60s

Review latency distribution after test:

/tool/traffic-generator/stats/latency-distribution/print

Scenario: Inject PCAP File

Replay captured traffic from a PCAP file (RouterOS 7.21+):

/tool/traffic-generator/inject-pcap file=capture.pcapng interface=ether1

Global Settings

Configure global Traffic Generator behavior:

/tool/traffic-generator/set \
    latency-distribution-max=100us \
    measure-out-of-order=yes \
    stats-samples-to-keep=1000 \
    test-id=1

Setting	Description
latency-distribution-max	Maximum latency range for distribution buckets
measure-out-of-order	Enable OOO packet detection (CPU-intensive on multi-core)
stats-samples-to-keep	Number of sample records to retain
test-id	Identifier for distinguishing multiple tests

Verification

Check 1: Verify Feature Is Enabled

/system/device-mode/print

Look for traffic-gen in the enabled features.

Check 2: Verify Port Configuration

/tool/traffic-generator/port/print

Expected: Ports listed without I (inactive) flag.

Check 3: Verify Template MAC Resolution

/tool/traffic-generator/packet-template/print detail

Check assumed-mac-dst has a valid MAC address, not 00:00:00:00:00:00.

Check 4: Run Quick Test

/tool/traffic-generator/quick interface=ether1 mbps=10 duration=5s

Expected: Statistics display showing TX and RX counters incrementing.

Troubleshooting

Symptom	Cause	Solution
”traffic generator is disabled”	Feature locked in device-mode	Enable via /system/device-mode/update traffic-gen=yes with reset button
No RX packets	Packets not returning	Verify routing, check topology, ensure return path exists
assumed-mac-dst is 00:00:00:00:00:00	ARP not resolved	Set ip-gateway or verify destination is reachable
High packet loss	Interface saturated or DUT overloaded	Reduce mbps/pps rate; check DUT CPU
Out-of-order not measured	Disabled by default on multi-core	Enable with measure-out-of-order=yes
Cannot capture generated packets	By design limitation	Use separate sniffer device on the wire
Template errors	Invalid header-stack combination	UDP requires IP; VLAN follows MAC only
Inconsistent results	Other traffic on test path	Isolate test network; test during maintenance

Debug: Check CPU During Test

/system/resource/print

High CPU (>90%) indicates the traffic generator or DUT is the bottleneck.

Debug: Verify Routing Path

/ip/route/print where dst-address~"10.0.0"

Ensure routes exist for both source and destination networks.

Debug: Check Interface Errors

/interface/ethernet/print stats

Look for TX/RX errors, drops, or FCS errors.

Common Mistakes

• Forgetting return path - Traffic Generator needs packets to return for statistics; ensure bidirectional routing
• Using single interface - Proper testing requires at least two interfaces (TX and RX)
• Stream ID conflicts - Each stream must have a unique num value (0-15)
• Testing on production networks - Can saturate links; use isolated test networks
• Assuming packets reach firewall - Generated packets bypass local firewall on TX interface
• Not updating MACs after topology change - Run set on templates to refresh assumed values

Tips

FastPath Performance: Traffic Generator automatically uses FastPath when available. Ensure interfaces support FastPath for maximum throughput.

Isolate Tests: For accurate results, use dedicated test interfaces not carrying production traffic.

Incremental Rate Testing: Start at low rates and increase gradually to find the maximum forwarding rate without packet loss.

Multiple Streams: Use different stream IDs to test multiple traffic classes simultaneously and measure per-class performance.

DSCP Testing: Set ip-dscp in templates to test QoS policy handling for different traffic classes.

Related Topics

Performance Testing

• Bandwidth Test - point-to-point throughput testing
• Speed Test - comprehensive performance testing
• Profile - CPU profiling for performance analysis

Traffic Analysis

• Torch - real-time traffic analysis
• Packet Sniffer - capture network traffic
• Traffic Monitor - interface statistics

Network Configuration

• Firewall Basics - allow generated traffic
• Simple Queues - test QoS configurations

Reference

• MikroTik Traffic Generator Documentation

Global Properties (/tool/traffic-generator)

Property	Type	Default	Description
latency-distribution-max	time	100us	Maximum latency range for distribution
measure-out-of-order	yes/no	CPU-dependent	Enable OOO detection
stats-samples-to-keep	integer	100	Statistics samples retained
test-id	integer [0..255]	0	Test identifier

Port Properties (/tool/traffic-generator/port)

Property	Type	Default	Description
name	string	-	Port identifier
interface	string	-	Associated interface
disabled	yes/no	no	Disable port

Packet Template Properties (/tool/traffic-generator/packet-template)

Property	Type	Default	Description
name	string	-	Template identifier
header-stack	list	ip	Header sequence: mac, vlan, ip, udp, raw
port	string	-	Associated port
interface	string	-	Direct interface (creates dynamic port)
ip-src	IP/Mask	-	Source IP address
ip-dst	IP/Netmask	-	Destination IP address
ip-gateway	IP	-	Next-hop for routing
ip-ttl	integer [0..255]	-	Time-to-live
ip-dscp	integer [0..255]	-	DSCP value
ip-protocol	protocol	-	IP protocol
mac-src	MAC	-	Source MAC address
mac-dst	MAC	-	Destination MAC address
udp-src-port	integer [0..65535]	-	Source UDP port
udp-dst-port	integer [0..65535]	-	Destination UDP port
vlan-id	integer	-	VLAN identifier
vlan-priority	integer	-	VLAN priority
data	uninitialized/specific-byte/incrementing/random	uninitialized	Payload fill method
data-byte	hex [0..FF]	0	Byte for specific-byte fill

Stream Properties (/tool/traffic-generator/stream)

Property	Type	Default	Description
name	string	-	Stream identifier
num	integer [0..15]	0	Unique stream number
disabled	yes/no	no	Disable stream
port	string	-	Associated port
tx-template	string	-	Packet template reference
mbps	integer	0	Target rate in Mbps
pps	integer	0	Target rate in packets/sec
packet-size	integer or range	0	Packet size (supports ranges like 64-1500)

Quick Mode Parameters

Parameter	Type	Description
interface	string	Interface for quick test
mbps	integer	Target rate in Mbps
pps	integer	Target rate in packets/sec
packet-size	integer	Packet size
duration	time	Test duration
tx-template	string	Template to use
stream	string	Stream to use

Commands

Command	Description
quick	Run interactive test with terminal output
start	Start background test
stop	Stop running test
inject	Inject raw data into interface
inject-pcap	Inject from PCAP file (v7.21+)