Art-Net is a

royalty-free Royalty-free (RF) material subject to copyright or other intellectual property rights may be used without the need to pay royalties or license fees for each use, per each copy or volume sold or some time period of use or sales. Computer standard ...

communications protocol A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchr ...

for transmitting the

DMX512-A DMX512 is a standard for digital communication networks that are commonly used to control lighting and effects. It was originally intended as a standardized method for controlling stage lighting dimmers, which, prior to DMX512, had employed ...

lighting control protocol and

Remote Device management {{manual, date=February 2016 Remote Device Management (RDM) is a protocol enhancement to USITT DMX512 that allows bi-directional communication between a lighting or system controller and attached RDM compliant devices over a standard DMX line. Th ...

(RDM) protocol over the

User Datagram Protocol In computer networking, the User Datagram Protocol (UDP) is one of the core communication protocols of the Internet protocol suite used to send messages (transported as datagrams in packets) to other hosts on an Internet Protocol (IP) network. ...

(UDP) of the

Internet protocol suite The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suit ...

. It is used to communicate between "nodes" (e.g., intelligent lighting instruments) and a "server" (a lighting desk or general purpose computer running lighting control software).

Facilities

Art-Net is a simple implementation of DMX512-A protocol over UDP in which lighting control information is conveyed in IP packets, typically on a private

local area network A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building. By contrast, a wide area network (WAN) not only covers a larger ...

such as

Ethernet Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...

. Supported functions include transmitting and receiving lighting data (e.g., fader levels for individual lights, positions of movable lights); management functions such as detecting nodes, updating node control parameters, and transmitting

timecode A timecode (alternatively, time code) is a sequence of numeric codes generated at regular intervals by a timing synchronization system. Timecode is used in video production, show control and other applications which require temporal coordination ...

s; and functions that allow nodes to "subscribe" to "publisher" nodes so that, for example, nodes A and B can subscribe to node C (C will unicast information to A and B).

Versions

Art-Net has gone through four versions which are claimed to be interoperable. Art-Net I used broadcasts extensively, giving a universe limit of approximately 40. Art-Net II mostly uses unicast packets, and addresses 256 universes. Art-Net III, released in 2011, addresses issues in managing larger numbers of universes, up to 32,768. A further version, Artnet IV was released in 2016. Internally to the protocol, it is referred to as version 14.

Addressing

In its simplest implementation, nodes all broadcast, originally on the 2.0.0.0/8 networks. Addressing is typically fixed per node, often locked to the

MAC Address A media access control address (MAC address) is a unique identifier assigned to a network interface controller (NIC) for use as a network address in communications within a network segment. This use is common in most IEEE 802 networking techno ...

and an "OEM" code allocated to the manufacturer, and jumper settings. Networks can use

DHCP The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on Internet Protocol (IP) networks for automatically assigning IP addresses and other communication parameters to devices connected to the network using a cli ...

or statically configured IP addresses, and use

unicast Unicast is data transmission from a single sender (red) to a single receiver (green). Other devices on the network (yellow) do not participate in the communication. In computer networking, unicast is a one-to-one transmission from one point in ...

packets for greater network efficiency. The protocol can address 32768 DMX "universes", each of 512 channels, limited by bandwidth. The fixed addressing can be problematic in networks with other addressing requirements. Revision Q of the protocol addressed this problem by adding 10.0.0.0/8 as an addressing scheme. For node discovery, broadcast packets are used.

Packet format

The following table shows a typical packet, ''ArtDMX'', for transmitting lighting values. It is sent to the fixed UDP port 0x1936 (6454 decimal). The pink portion is the same on all Art-Net packets; the green portion is variable. The ''opcode'' (given in little endian) tells the recipient this is a packet containing DMX data in the ''data'' portion, intended to be output of the specified ''universe''. ''Sequence'' is a sequential number between 1 and 255 allowing the recipient to reorder packets to address

out-of-order delivery In computer networking, out-of-order delivery is the delivery of data packets in a different order from which they were sent. Out-of-order delivery can be caused by packets following multiple paths through a network, by lower-layer retransmissio ...

(this value is set to 0 to disable this feature); ''physical'' is an information packet showing the original physical universe of this data, if required. Then follows up to 512 lighting values in the range 0 to 255. Conceptually, this packet is broadcast to all nodes; but is ignored by all nodes except the one which is configured to listen for this universe. In practice the packet is typically unicast to the correct node.

References

{{Reflist

External links