Entertainment Control Networks

Networks designed for entertainment control are purpose-built to get real-time data between devices quickly, efficiently, and reliably with the lowest latency possible.

Overview

Entertainment control networks are designed to be risk-averse to avoid downtime, as well as scalable so that new equipment can be easily integrated without reconfiguration. They are also designed to use very little bandwidth under typical conditions, keeping the network open so that it can be flooded with data for immediate real-time control.

As a result, the unique configurations and priorities of entertainment control networks differ from those of standard computer networks. It is likely not a problem if you send an email and it takes a few minutes to arrive, but even a short delay when changing lighting levels can be undesirably obvious to an audience.

Eos communication in Multi-Console Sessions is built on multicast data distribution, and both Streaming ACN (sACN) and v4 of Art-Net use multicast to transmit address levels. Configuring a control network to manage the efficient distribution of multicast traffic reduces unnecessary data transmission and ensures that data only reaches the appropriate destinations. See Why Multicast. Networks improperly configured for multicast may not be able to transmit multicast data. In an unconfigured system, multicast is treated as broadcast data. See Network Protocols > Multicast.

Purpose-built devices, such as ETC Conductor or ETC SiteBox, can allow the safe use of Internet-connected features (such as routing, remote monitoring, and internet time) with entertainment control networks.

Digital Multiplex 512 (DMX)

ANSI/TIA E1.11

Digital Multiplex 512 (DMX512, or most commonly simply DMX) is a protocol developed and standardized for control of lighting and entertainment devices in traditional wired systems. The Ethernet-based network systems discussed in this section allow entertainment control networks to be scaled beyond 512 addresses over a single cable.

Universes

A single run of DMX can control up to 512 individual addresses, each of which can be set to a value between 0 and 255 (often expressed in Eos and other lighting controllers as a percentage). A single DMX universe can be said to contain 512 addresses, and any address numbers higher than 512 must be carried in a subsequent universe. Universes are typically how entertainment control networks organize their data addresses.s

Universes and addresses are sequentially numbered, typically represented in one of two ways.

• Port / Offset - the universe number and the address number, separated by a slash.
  • For example, 2/6 would be the sixth address in the second DMX universe.
• Absolute - just the address number, including all preceding universes.
  • 2/6 expressed as an absolute address would be 518 (the 512 addresses in universe 1 plus the 6 in universe 2).
  • Absolute addresses can be calculated with the formula ((universe number - 1) * 512) + any address offset.

Network-based protocols like Streaming ACN (sACN) and Art-Net maintain this numbering, while providing access to far more universes than would be practical in a DMX-based system.

DMX is still recommended for bridging the gap between network infrastructure and lighting equipment, as it can be daisy-chained to multiple lighting fixtures without increasing the Network Width.

Network Isolation

General best practice is to isolate entertainment control networks from other networks, including the global Internet.

Physical LAN Isolation

A Local Area Network (LAN) is any group of connected switches and nodes.

ETC recommends keeping any entertainment control LANs entirely physically separated from other networks whenever possible or when security is a concern.

A complete network infrastructure can be dedicated to the lighting system where the network’s sole purpose is connecting lighting devices. This has long been recommended by ETC and remains the best practice. It not only increases security, but also reduces coordination demands and simplifies system design, implementation, and troubleshooting.

Logical VLAN Isolation

When physical separation of your entertainment control system from other network infrastructure is impossible, logical isolation is an acceptable secondary option. A Virtual Local Area Network (VLAN) is a digital subdivision of a physical LAN.

Commonly used outside entertainment control for privacy and security, VLANs can be used to create a separate virtual network within an existing physical infrastructure, similar to partitioning a hard drive.

VLAN-enabled managed switches create an internal model of multiple virtually-separated LANs, each of which is given a VLAN ID. These IDs are then assigned to the ports being isolated into that virtual portion of the network. Network traffic is similarly tagged with an ID which the switches use to route the traffic to the correct virtual location. The data is untagged at the end and delivered to the appropriate ports within the VLAN.

VLANs are not intended for true separation of network traffic; a physically-separated LAN is still preferred. VLANs are still constrained by the overall bandwidth limitations of their physical network, just as partitioning a hard drive does not increase the amount of available space.

Eos only supports Layer 2 VLANs, where the network switch architecture handles the virtual network separation. Layer 3 VLAN interfaces, which allow the inspection and routing of packets into other networks, are not supported in entertainment control networks for the same reasons that Routers are not recommended.

The Internet

ETC does not recommend connecting entertainment control networks to the Internet.

• Devices accessing the Internet can consume significant bandwidth, which can introduce control latency.
• The network becomes open to security risks from bad actors.
• Viruses can pose a danger to network hardware and software, even the embedded operating systems used in most Eos devices.

Static and Dynamic Addressing

There are two ways to assign Internet Protocol (IP) addresses to devices in entertainment control networks.

• Static - manually choosing and assigning an IP address to each individual device in the network.
  • Offers predictability and a greater level of control over the addresses chosen.
  • Requires more human management, especially as a network grows and changes.
• Dynamic - using a Dynamic Host Configuration Protocol (DHCP) server to automatically assign addresses to network devices.
  • Saves time and effort, especially in larger or more complex networks.
  • Less consistent for troubleshooting, show control, and integration.

A combined approach can offer the best of both worlds. Once a device has been statically addressed, it will not request or take an IP address from a DHCP server. This is best applied to centralized control devices less likely to move or change, such as consoles and dimmer racks. Meanwhile, a DHCP server can remain active in the same network to dynamically address infrastructure and accessory devices, such as gateways and smartphone remotes.

Time Servers

A time server is a device that establishes the actual time and distributes that information to other nodes. Most time servers transmit this information via Network Time Protocol (NTP).

Eos consoles are capable of acting as time servers, enabled in the Eos Configuration Utility via Settings > Network > Time Service (SNTP). Many ETC products, such as Paradigm Architectural Control, can also provide time services.

ETC recommends the use of time servers on all entertainment control networks in order to keep all nodes synchronized to the same consistent time.

Only one time server should be active at a time in a LAN to prevent time conflicts or changes.