ArtNet Protocol Explained: Features, Limitations, and Network Impact

The DMX512 protocol – Digital Multiplex 512 – was created in 1986. As an older protocol, it has several limitations. A single DMX512 line supports a maximum of 32 devices, and with each additional node, the signal weakens. The maximum DMX512 cable length is 300 meters. The protocol's unidirectional nature limits control, diagnostics, and monitoring capabilities. Additionally, DMX512 signals are susceptible to electromagnetic interference, and the data transmission speed is 250 kbps, which is insufficient for modern lighting systems.

DMX512 is inadequate for lighting installations requiring control over high-capacity intelligent LED devices with numerous parameters and dynamic effects. Many functions require a large number of DMX channels since each individual function uses a separate channel. Even if not all fixture capabilities are used in a particular show, freeing up channels, DMX512 remains limited for creating impressive and large-scale lighting performances.

Ethernet is a standardized technology group used for building local and metropolitan area networks, transmitting data between devices in packets over cables.

Using Ethernet in professional stage lighting opens new possibilities, significantly surpassing the capabilities of traditional DMX512. The main advantages include:

1. High bandwidth – Ethernet transmits data 40–400 times faster than DMX512.
2. Availability and cost-effectiveness – Ethernet allows integration of a wide range of affordable computer hardware, such as switches and wireless devices, into lighting systems.
3. Ease of cabling – Ethernet uses inexpensive and easy-to-install cables, simplifying installation and certification of lighting cable systems.
4. Integration with existing infrastructure – Many venues requiring device networks already have Ethernet installed, simplifying project design.
5. Reliability – The "star" topology of Ethernet provides greater system resilience compared to the multipoint DMX512 bus topology. The bus topology is highly vulnerable: failures can paralyze the entire network, troubleshooting is complex, and adding new devices reduces overall performance. The "star" topology eliminates these drawbacks.

The transition to network protocols is driven by the need for more flexible and scalable lighting control. These protocols are resistant to interference and offer high-speed transmission.

Art-Net is a protocol released by Artistic License in 1998 that transmits DMX512 data over Ethernet as IP packets.

Art-Net uses the User Datagram Protocol (UDP) for network transmission. UDP is a connectionless protocol, meaning it does not establish a connection between the server and nodes before data transmission, unlike TCP. While UDP does not guarantee data delivery, it minimizes latency – a critical factor for lighting designers.

ArtNet requires conversion, as most lighting fixtures operate on DMX.

Art-Net has evolved through several versions, each adding new features and improving protocol performance.

• Art-Net I: The first version, released in 1998, used broadcast data transmission. Art-Net I was designed for 10 Mbps networks, supporting up to 10 DMX universes, with an effective limit of around 40 universes. The rise of RGB devices led to a surge in channel demand, while non-addressable data packets caused network flooding and instability.
• Art-Net II: The second version, released in 2006, switched to unicast data transmission. Initially, an Art-Net II console broadcasts data like Art-Net I. However, it then sends queries to determine which nodes use specific DMX universes and switches to unicast transmission. Art-Net II significantly reduced network load, enabling scalability based on network bandwidth. Its effective limit is 256 DMX universes.
• Art-Net III: The third version, introduced in 2011, greatly expanded the addressable space, supporting up to 32,768 DMX universes. It also added a binding feature, allowing DMX universes to be assigned to specific devices.
• Art-Net IV: The fourth version, launched in 2016, addressed multi-addressing issues by introducing a new method for gateway operation. This approach allows a gateway with built-in routing to support over 1,000 DMX ports under a single IP address, assigning each DMX port a fully independent universe. These capabilities are achieved by adding extra data fields within Art-Net packets to identify each DMX port.

Art-Net IV is backward compatible with previous versions.

Art-Net offers a number of advantages over DMX512, which are especially valuable in professional stage lighting. One of its primary strengths is capacity. Art-Net enables the transmission of large amounts of data over a single physical line. Each node supports up to 1024 DMX channels, corresponding to two universes per IP address. Every 16 universes are grouped into a subnet, 16 subnets form a network, and the maximum number of networks is 128. Theoretically, the system can support up to 32,768 nodes with 512 DMX channels each. In practice, the number of transmitted universes is limited by the network’s bandwidth. Meanwhile, Ethernet’s bandwidth continues to grow – not only is Fast Ethernet (100 Mbps) available, but Gigabit Ethernet is also in use, with speeds ranging from 1 to 100 Gbps depending on the cabling, network cards, and routers employed.

Remote switching of DMX512 inputs and outputs, along with support for the RDM standard, enables remote control of devices on the network and automates the address assignment process.

Art-Net also provides the ability to merge DMX512 data in either highest-priority or highest-value formats, facilitating data merging and simplifying lighting control in complex projects. 

Moreover, Art-Net is a free protocol supported by a wide range of manufacturers, including Sundrax.

The maximum length of an Ethernet cable is approximately 100 meters, compared to 300 meters for DMX512. It is also worth noting that an Ethernet topology based on a “star” configuration requires a greater amount of twisted pair cabling. However, the relatively low cost of Ethernet switches and the numerous advantages of local area networks, as outlined above, compensate for these drawbacks. 

ArtNet and sACN

Art-Net 4 offers flexibility in managing data sources, allowing for the combination of protocols – in practice, using Art-Net for remote monitoring and configuration while simultaneously employing sACN for real-time command transmission to lighting fixtures. 

Some installations and specifications require the use of sACN, which is an accredited ANSI E1.31 standard. sACN surpasses ArtNet in scalability, supporting up to 65,535 DMX universes compared to 32,768 in ArtNet. However, unlike Art-Net, sACN does not support RDM, which may cause some inconvenience. 

Art-Net supports the remote device management protocol – RDM. RDM is an extension of the DMX protocol that allows the controller to request information from nodes about their status and configuration. Often, fixtures compatible with Art-Net and DMX include an option to respond to such requests. 

The RDM protocol transmits its data alongside DMX lighting commands – DMX is sent with a start code of 0x00, while RDM uses 0xCC. When a lighting fixture receives the 0xCC start code, it recognizes the packet as RDM and begins processing it. Meanwhile, older devices that do not support RDM simply ignore packets with a 0xCC start code without attempting to read them. 

Some lighting fixtures that do not support the RDM protocol may malfunction upon receiving RDM commands. Professional lighting control devices, such as splitters (see splitters), are equipped with built-in RDM filters that allow for selective disabling of RDM. 

Data exchange via the RDM protocol is divided into three types: 

• Discovery: for detecting RDM devices connected to the DMX network. The controller sends a broadcast request, and RDM devices, upon receiving it, respond by identifying themselves and their capabilities. 
• Unicast: for interacting with a specific RDM device. The controller sends a request to a specific device using its unique identifier (UID), allowing it to obtain information about the device’s status, configure its settings, and manage its functions. 
• Broadcast: for sending commands or requests to all RDM devices connected to the network. The controller sends a broadcast message, which is received by all RDM devices. This type of communication can be used for firmware updates, setting uniform parameters for a group of fixtures, or sending commands that must be executed by all recipients. Broadcast transmission does not require responses from devices, except during the discovery process. 

RDM is indispensable in venues and setups where access to installed equipment is difficult – for example, when equipment is mounted on trusses and in rigging systems. The protocol allows for full utilization of modern lighting equipment and helps avoid issues associated with the lack of device feedback.

Art-Net boasts extensive data transmission capabilities, including file transfers. Communication is carried out over UDP, where each packet format defines a data field within the encapsulated UDP packet. Packet formats are described similarly to C language structures, with data elements represented by INT8, INT16, or INT32 types depending on the number of bits. Art-Net packets do not include hidden padding bytes, except for possible rounding to a multiple of 2 or 4 bytes at the end of the packet. Any extra bytes at the end of a correctly received packet are ignored. 

The Art-Net data format includes several packet types:

• ArtCommand: for sending property-set style commands, either unicast or broadcast; 
• ArtNzs: for transmitting DMX512 data with non-zero start codes (other than RDM), with an identical format for transmission from node to controller, node to node, and controller to node; 
• ArtDmx: for transmitting DMX data, containing information about brightness levels for 512 DMX channels; 
• ArtPoll: for discovering Art-Net devices on the network, where the controller sends an ArtPoll packet and Art-Net devices respond with an ArtPollReply packet; 
• ArtAddress: for configuring the addressing of Art-Net devices; 
• ArtTimeCode: for synchronizing lighting with other stage elements, such as video and audio.

When constructing a network for lighting control, addresses are configured via a lighting console or a computer running appropriate software. Each lighting fixture, which has its own unique address for network identification, serves as a node that receives commands. The lighting console or computer with lighting control software acts as the server, responsible for sending commands to the nodes. These commands adjust tilt, pan, speed, colors, dimmer, focus, zoom, and other functions of the lighting fixtures. 

The Art-Net protocol supports both dynamic IP addresses managed by DHCP and static addresses. By default, Art-Net devices are factory-configured to use Class A IP addresses, which allows them to interact directly without the need for a DHCP server. 

Art-Net devices communicate with one another through nodes, which can take the form of Art-Net converters to physical DMX512, lighting fixtures, or equipment with built-in Art-Net interfaces. Nodes can receive data from the server, and the server can send packets to all or individual Art-Net nodes. Nodes can be “bound” to a specific signal source, while a computer or console can be set to ignore certain nodes. A simple way to implement the protocol is via broadcast transmission, similar to how a radio station broadcasts a signal that any listener can choose to receive. 

Professional devices for addressing, filtering, and routing data enable the creation of complex Art-Net network configurations for precise lighting control even in large installations.

Broadcast transmission – a method in which one or several senders transmit information to all “participants” of a network – is especially useful for service network packets that all devices must receive. However, when most devices do not require this information, broadcasting becomes inefficient. 

Broadcast transmission has the following drawbacks: 

• Network Overload: Every device processes every packet, which can lead to overload under high traffic; 
• Data Loss: An excess of broadcast packets can cause unstable network performance; 
• Vulnerability: The network becomes susceptible to attacks, where an intruder may overload it with broadcast packets. 

Art-Net utilizes broadcast transmission, resulting in a constant distribution of packets. Consequently, Art-Net may cause switches to become overloaded when processing a large number of streams. 

This issue arises because DMX is transmitted in fragments addressed to specific nodes. Consider a scenario where a switch is connected to a computer generating a data stream and has five switch ports. Due to broadcast transmission, this data stream is distributed to all ports of the switch. 

Not all switches can properly handle such traffic. High-performance devices, such as those from Cisco, attempt to optimize broadcast packet processing, but budget models may become overloaded and freeze as a result of broadcast traffic. 

Even though switches are designed to handle significant data flows (for example, 10–100 Mbps), broadcast traffic as low as 1 Mbps can be critical. Even Gigabit switches may experience difficulties processing such volumes of broadcast data. 

If an issue is caused by hardware failure, logically, it should manifest locally or, at least, more intensely in a specific network segment. However, if a network that has been running stably suddenly begins to experience failures without any apparent cause, one might suspect broadcast flooding.

To ensure reliable and efficient operation of Art-Net-based lighting systems, it is necessary to consider the protocol's characteristics and carefully plan the infrastructure. To minimize issues related to Art-Net broadcast traffic, it is recommended to: 

1. Limit the Number of Universes. The primary issue is not the number of devices, but rather the number of universes in use. Switches can become overloaded when handling a large number of universes because they process broadcast traffic differently from unicast traffic. It is recommended to limit the number of universes per physical port to 8–10 to prevent overload and to group related fixtures into a single universe to optimize traffic. 
2. Zone the Lighting. Zoning allows for effective grouping of fixtures. Geographical zoning enables the adaptation of lighting to specific areas of a space, such as stages, halls, indoor and outdoor areas, as well as zones for special effects. Functional zoning divides lighting by purpose: working versus decorative, static versus dynamic, primary versus emergency. Administrative zoning ensures access control and the segregation of zones for different technician teams, as well as designating critical areas that require enhanced protection. 
3. Use Subnets. Dividing the Art-Net network into subnets and employing structured IP addressing helps to restrict the spread of broadcast packets, thereby reducing the load on switches. 
4. Integrate Managed Switches with QoS and VLAN Support for prioritizing Art-Net traffic. 
5. Implement Network Monitoring Devices, an Alert System for Failures, Hardware Redundancy, and Automatic Switching to Backup Channels.

As we've explored throughout this article on ArtNet protocol, traditional DMX512 presents significant limitations for modern lighting design:

• Maximum 32 devices per line
• 200-meter maximum transmission distance
• Susceptibility to electromagnetic interference
• 250 kbit/s data transfer speed
• Limited 512 channels per universe—easily exhausted by today's feature-rich fixtures

Sundrax converters transform ArtNet, sACN, and other Ethernet protocols into DMX512 signals that lighting fixtures understand, while adding capabilities that elevate entire lighting systems:

Intelligent Signal Merging

Multiple lighting consoles can control a single fixture set with precise prioritization through HTP, LTP, AUTO, and PRIORITY merging modes—ideal for complex productions requiring multiple operators.

Bidirectional Operation

All ports can function as inputs or outputs, enabling flexible system architecture where DMX signals can travel over IP networks and convert back at endpoints for precise fixture control.

Emergency Trigger Functionality

Models like GigaJet20 Pro, GigaJet Pro, ArtGate Pro, and ArtGate DIN feature trigger inputs that automatically activate pre-programmed emergency lighting scenarios—critical for venue safety protocols.

• PRO Series: Rack-mountable units just 11cm deep with 1U profile
• Solid Series: Waterproof IP44-rated duralumin housing for truss mounting
• DIN Series: Space-efficient rail-mount converters with terminal blocks
• Arma Series: Extreme temperature tolerance (-40°C to +70°C) for outdoor installations
• Compact Series: Ultra-portable junction box housing
• Board Series: Miniature OEM solutions for custom integration

• PRO Series: Rack-mountable units just 11cm deep with 1U profile
• Solid Series: Waterproof IP44-rated duralumin housing for truss mounting
• DIN Series: Space-efficient rail-mount converters with terminal blocks
• Arma Series: Extreme temperature tolerance (-40°C to +70°C) for outdoor installations
• Compact Series: Ultra-portable junction box housing
• Board Series: Miniature OEM solutions for custom integration