Introduction: KNX IP Router
A KNX IP Router is the central communication hub that connects multiple lines or areas via Ethernet (IP) instead of traditional twisted-pair (TP) couplers. It uses the KNXnet/IP protocol to transmit telegrams efficiently between lines, enabling fast, reliable, and scalable communication for large installations.
In simple terms, the KNX IP Router functions like a network backbone—it routes messages over an LAN network, drastically improving speed and flexibility in complex building automation systems.
✅ Key Benefits
- Faster inter-line communication via Ethernet
- Simplified wiring—no need for physical line couplers
- Remote access & monitoring through IP
- Scalability for large commercial or multi-building installations
- Secure communication with IP Secure
Read our Beginner’s Guide to KNX Home Automation →
How a KNX IP Router Works
The KNX IP Router translates telegrams into LAN packets and transmits them using KNXnet/IP Routing (multicast) across Ethernet networks. This allows different system areas or lines to communicate through an IP backbone.
Key Working Modes:
- Routing Mode:
Used for communication between lines and areas. Telegrams are transmitted using multicast to all connected routers. - Tunneling Mode (optional):
Some routers also support tunneling, enabling direct programming connections from ETS, acting like an IP Interface. - IP Secure Mode:
Encrypts all telegrams to prevent unauthorized access and ensure data integrity.
In a large installation, you might have:
- Multiple lines on each floor
- Each line connected to an IP Router
- All routers linked through Ethernet to form the backbone
This structure offers high reliability and fast routing of telegrams throughout the building.
Why Use KNX IP Routers in Modern Installations
With modern buildings integrating hundreds of KNX devices, IP Routers are now essential for:
- Centralized communication between multiple lines
- Load balancing to reduce telegram congestion
- Faster diagnostics and ETS access
- Integration with IP visualization systems
- Remote programming and monitoring
Without IP routers, large systems require multiple line couplers, increasing wiring complexity and latency. By using Routers, all communication shifts to a high-speed Ethernet backbone, reducing delays and simplifying design.
Technical Specifications (Typical)
| Parameter | Specification |
|---|---|
| Network Type | Ethernet 10/100 Mbps |
| Bus Connection | TP (Twisted Pair) |
| Power Supply | 12–30 V DC or via bus |
| Protocol Support | net/IP Routing, net/IP Tunneling |
| Max Tunneling Connections | 5–10 (model dependent) |
| Routing Function | Multicast routing between lines |
| IP Configuration | DHCP / Static |
| Security | KNX IP Secure (EN 50090-3-4) |
| Mounting | DIN Rail (2–4 TE) |
| Operating Temperature | -5°C to +45°C |
| Web Interface | Diagnostic and configuration access |
KNX IP Router vs IP Interface
| Feature | IP Router | IP Interface |
|---|---|---|
| Primary Function | Interconnects KNX lines via IP | Provides ETS access to KNX bus |
| Communication Type | Multicast (Routing) | Point-to-Point (Tunneling) |
| Connections | Multiple routers on Ethernet | 1:1 or few simultaneous connections |
| Use Case | Large/multi-line installations | Single line or small project |
| Configuration Complexity | Moderate to high | Simple |
| Cost | Higher | Lower |
| Supports KNX IP Secure | Yes (new models) | Yes (select models) |
See detailed comparison: KNX IP Router vs Interface →
Common Use Cases
- Large Commercial Buildings: Interconnect multiple floors or wings through a shared Ethernet backbone.
- Campus Installations: Link multiple buildings into a single network.
- Hotels and Hospitals: Provide fast communication between lighting, HVAC, and access control.
- Hybrid Systems: Connect visualization servers (like Thinka or Gira HomeServer) to KNX via LAN backbone.
- Remote Diagnostics: Access devices across buildings without direct TP connection.
Top KNX IP Router Brands & Models
MDT SCN-IP100.03
- Functions: Routing + Tunneling
- KNX IP Secure: Supported
- Connections: Up to 5 simultaneous tunnels
- Web Server: Integrated diagnostics and packet monitor
- DIN Width: 2 TE
- Highlights: Reliable, ETS6-ready, and perfect for secure large systems
Theben IPsecure 7169202
- Security: Full KNX IP Secure support
- Connections: 8 tunnels + routing
- Setup: Auto IP via DHCP or manual
- Special Feature: Built-in filter table for optimized routing
- Use Case: Commercial/critical building automation
ABB IPS/S 3.1.1 Router
- Routing + Tunneling: Yes
- DIN Width: 2 modules
- Connections: 4 tunnels
- IP Config: DHCP/Manual
- Stability: Proven industrial-grade reliability
Weinzierl KNX IP Router 750
- Connections: 5 tunnels
- Routing Mode: net/IP Multicast
- Security: Optional IP Secure
- Feature: Web-based diagnostics and firmware updates
- Advantage: Compact design ideal for small panels
GIRA KNX IP Router 216800
- Connections: 5 tunnels + routing
- Power Supply: From bus
- Security: IP Secure
- Web Interface: Integrated
- Special Feature: Fast telegram routing with minimal latency
Hager TYF121
- Functions: Routing + Tunneling
- Power: Bus powered
- Configuration: Auto IP (DHCP)
- Best For: Medium-sized commercial projects
How to Configure a KNX IP Router in ETS6
- Physically Connect the Router:
Plug the device into the KNX bus and connect the Ethernet port to your LAN. - Detect Device in ETS:
Open ETS6 → Bus → Add Device → Scan for KNXnet/IP devices. - Assign Individual Address:
Typically, routers use addresses like1.0.0,1.1.0, etc., representing area/line coupling. - Configure IP Settings:
Choose DHCP or assign a static IP. Verify subnet matches your building network. - Enable Routing:
In device parameters, activate “Routing” mode for multicast telegram forwarding. - Enable IP Secure (if supported):
Add secure keys and link them with ETS project settings. - Save & Download Configuration:
Once configured, download to the device. - Test Communication:
Use ETS Diagnostics → Group Monitor to verify telegram flow between lines.
KNX IP Secure in Routers
Security has become a core requirement in connected buildings. IP Secure, introduced by the Association, encrypts all communication at the IP level.
Features:
- Encryption: AES-128 standard
- Authentication: Device identity verification
- Data Integrity: Protection against tampering
- Configuration: Managed via ETS6 using secure keys
Routers such as MDT SCN-IP100.03, Theben IPsecure 7169202, and GIRA 216800 fully support KNX IP Secure, ensuring compliance with EN 50090-3-4.
Integration with Building Management Systems
An IP Router allows seamless integration with:
- Visualization Systems: Gira HomeServer, Thinka, Zennio, Jung Facility Pilot
- BMS Platforms: BACnet, Modbus TCP, or MQTT via gateway
- AV/IT Systems: Crestron, Control4, or openHAB
- Remote Monitoring: Cloud-based dashboards through LAN connectivity
Network Design Example
Scenario:
A commercial building with 4 floors, each containing 3 lines.
Solution:
- One IP Router per floor connects all lines to Ethernet.
- Routers linked to a central network switch.
- All lines communicate via IP backbone using multicast.
Result:
- Faster telegram transmission
- Simplified diagnostics
- Scalable structure for future expansion
Troubleshooting Tips
| Issue | Cause | Solution |
|---|---|---|
| No inter-line communication | Multicast blocked by switch | Enable IGMP snooping / multicast support |
| ETS can’t connect | Wrong IP/subnet | Correct IP or DHCP settings |
| Telegram delay | Loop in network | Avoid multiple routing paths |
| Security error | Key mismatch | Re-synchronize KNX Secure keys in ETS |
| Device not detected | Firewall or port block | Open UDP ports 3671–3672 |
Best Installation Practices
- Use dedicated VLAN or subnet for LAN traffic.
- Enable IGMP snooping on managed switches to handle multicast efficiently.
- Label IP Routers by floor/line for easy maintenance.
- Always use shielded Cat6/Cat7 Ethernet cables for stable transmission.
- If using Secure mode, store all encryption keys safely.
Summary
A KNX IP Router transforms how KNX networks communicate, replacing physical couplers with fast Ethernet routing. It’s the perfect solution for medium-to-large installations requiring scalability, reliability, and secure connectivity.
By adopting Routers, professionals can create flexible architectures, enable remote commissioning, and ensure future-proof smart building networks.
Key Takeaways
- KNX IP Router = Digital backbone for multi-line systems.
- Operates in Routing (multicast) and Tunneling modes.
- Essential for large-scale and secure installations.
- Brands like MDT, Theben, ABB, Gira, Weinzierl dominate the market.
- Supports IP Secure for encrypted communication.
- Easy integration with visualization and BMS systems.
Conclusion
The KNX IP Router is not just another device — it’s the foundation that connects every corner of a smart building through a unified IP backbone. As systems grow in size and complexity, the router ensures fast communication, enhanced reliability, and top-tier security with KNX IP Secure.
For every integrator or consultant, mastering the Router is crucial to designing future-ready automation networks that can evolve with modern building demands.
