Control Protocols

These protocols are generally designed specifically for the control of entertainment control systems.

Architecture for Control Networks (ACN)

ANSI/TIA E1.17

Architecture for Control Networks (ACN) is a standardized set of network protocols that allows multiple entertainment control systems to operate within a single Internet Protocol (IP) network without conflicts. The protocol is modular in nature to assist with the development of extension protocols within the same infrastructure.

Streaming ACN (sACN)

ANSI/TIA E1.31

Streaming ACN (sACN) continuously streams lighting levels over a network. It is one of the most commonly-used protocols in network-based lighting control, and was developed as an extension of the ACN suite to allow the transmission of Digital Multiplex 512 (DMX) data within IP networks.

sACN constantly sends data over the network with continuous packet updates. As this would be an overwhelming amount of information for Unicast transmitters or Broadcast receivers, sACN relies on Multicast to efficiently distribute packets via User Datagram Protocol (UDP).

ACN and sACN both communicate using TCP/UDP port 5568.

Priority

All sACN packets contain a priority level value between 0 (lowest priority) and 200 (highest priority), defaulting in Eos to 100.

When a network has more than one source of sACN for the same universe, being sent to the same multicast address, (for example, an Eos console and a Paradigm architectural system), conflicts can arise if two sources attempt to control the same addresses. Assigning a priority to the data being sent can ensure that one source supersedes any others.

sACN priority overrides the highest-takes-precedence logic typically used in entertainment control systems (see Important Concepts > HTP vs. LTP). sACN levels sent at a higher priority will supersede levels from another source, even if the levels themselves are lower. For example, if Eos sends a 100% intensity command at 150 priority and Paradigm sends an 0% intensity command at 100 priority, the lower-priority packet is discarded, and Eos will set the lights to full.

When multiple sources of equal priorities attempt to control the same address, the receiving gateway decides how to handle the packets. ETC gateways will allow the highest level value to take precedence as normal.

All Eos devices and most other sACN-compatible hardware and software allow for two ways for packets to communicate sACN priority.

  • Per-Universe - a priority level for an entire control universe (512 addresses, see Universes) is sent in the packet header. Also referred to as per-port or per-source priority.
  • Per-Address - a priority level is sent with each address packet. Not supported by all devices. Also referred to as per-channel or slot-by-slot priority. See Patch > Protocols > sACN.

Art-Net

Art-Net is a royalty-free communications protocol that transmits both DMX and RDM data within Ethernet networks via User Datagram Protocol (UDP). It can be used on the same network as sACN without conflicts.

Better suited to rapid development than ratified standards like sACN, there have been several major versions of the Art-Net protocol.

  • Art-Net I - broadcast communication. Theoretical maximum of 40 universes.
  • Art-Net II - broadcast and unicast communication. Theoretical maximum of 256 universes.
  • Art-Net 3 - primarily unicast communication. Theoretical maximum of 32,768 universes.
  • Art-Net 4 - sACN for live control data, Art-Net for device discovery and management.

More information is available at the official Art-Net website, art-net.org.uk. Art-Net™ Designed by and Copyright Artistic Licence.

ETCNet2

ETCNet2 (or simply Net2) is an ETC proprietary protocol that used EDMX to transmit lighting level information within IP-based networks. EDMX transmits DMX levels over a TCP/IP network using only absolute addressing only, with no knowledge of universes. A single multicast data stream allowed control of up to 32,768 addresses.

Net2 packets also contain priority level values between 20 (lowest priority) and 1 (highest priority), defaulting to 10. Prioritization is otherwise handled the same way as in sACN.

Replaced by ETC Net3, Net2 is no longer in active development, but is still used in networks containing legacy Net2 gateways and hardware. Eos software v3.2.0 and later does not support Net2.

ETC Net3

ETC Net3 is an ACN-compatible protocol developed to replace Net2. Net3 uses sACN for live control data, and allows network configuration and discovery via multiple protocols, including RDM, Dynamic Host Configuration Protocol (DHCP), and Network Time Protocol (NTP).