sACN: The Complete Streaming ACN Guide

sACN (Streaming Architecture for Control Networks), also known as Streaming ACN or E1.31, is an ANSI/ESTA standard protocol for transmitting DMX512 lighting control data over IP networks. Developed as part of the larger ACN (Architecture for Control Networks) suite, sACN has become the preferred choice for professional lighting installations worldwide.

Unlike traditional DMX512 protocol which is limited to 512 channels over dedicated cables, sACN leverages standard Ethernet infrastructure to transmit thousands of universes simultaneously. This makes it ideal for large-scale installations like concert tours, theme parks, architectural lighting, and broadcast studios.

Key Features of sACN

• Massive Scale: Supports up to 63,999 universes (over 32 million channels)
• Multicast Efficiency: Uses IP multicast for efficient one-to-many data distribution
• Built-in Priority: Per-packet priority system (0-200) for source management
• Official Standard: ANSI E1.31 ensures interoperability across manufacturers
• Synchronization: Native support for cross-universe synchronization
• Source Naming: Human-readable source identification for easier troubleshooting

The E1.31 Standard

sACN is formally defined in the ANSI E1.31 standard, maintained by ESTA (Entertainment Services and Technology Association). The current version, E1.31-2018, includes enhancements for synchronization and discovery. Being an official standard means:

• Guaranteed interoperability between compliant devices
• Well-documented specification for implementers
• Regular updates through a formal standards process
• Wide industry adoption and manufacturer support

Both sACN and Art-Net are excellent protocols for transmitting DMX data over networks. For a detailed comparison, see our Art-Net & sACN networking guide. Here's a quick summary of when to choose each:

Feature	sACN (E1.31)	Art-Net
Standard Type	ANSI/ESTA official standard	De facto industry standard
Transmission Method	Multicast (primary)	Broadcast/Unicast
Universe Capacity	63,999 universes	32,768 universes
Priority System	Yes (0-200 per packet)	Limited
Network Requirements	Managed switches with IGMP	Works on basic networks
UDP Port	5568	6454
Best For	Large professional installations	Maximum compatibility

Choose sACN When:

• Building large-scale installations with many universes
• Using multiple control sources that need priority management
• Working in professional environments with managed network infrastructure
• Requiring precise synchronization between universes
• Network efficiency is critical (multicast reduces bandwidth)

Choose Art-Net When:

• Maximum device compatibility is the priority
• Working with consumer-grade network equipment
• Connecting to older or legacy equipment
• Network doesn't support multicast properly

sACN Multicast IP Range

sACN uses a specific multicast IP address range defined in the E1.31 standard:

Each sACN universe is assigned a unique multicast address within this range. The address is calculated based on the universe number:

sACN IP Address Examples

Universe	Multicast IP Address	Calculation
1	239.255.0.1	(0 × 256) + 1 = 1
10	239.255.0.10	(0 × 256) + 10 = 10
255	239.255.0.255	(0 × 256) + 255 = 255
256	239.255.1.0	(1 × 256) + 0 = 256
1000	239.255.3.232	(3 × 256) + 232 = 1000
63999	239.255.249.255	(249 × 256) + 255 = 63999

UDP Port Configuration

sACN transmits all data on a single UDP port:

Ensure this port is open on any firewalls between sACN sources and receivers. Unlike Art-Net which uses port 6454, sACN's port 5568 is officially registered with IANA.

Network Requirements

• Bandwidth: Each universe at 44Hz requires approximately 22 Kbps
• Latency: Keep network latency below 10ms for smooth operation
• Switches: Use gigabit switches for installations with many universes
• IGMP Snooping: Enable on managed switches to optimize multicast traffic

Why Multicast Matters

Multicast is what makes sACN efficient. Instead of sending separate copies of data to each receiver (unicast) or flooding the entire network (broadcast), multicast allows one transmission to reach only the devices that need it. This is crucial for large installations with hundreds of fixtures.

IGMP Snooping Configuration

IGMP (Internet Group Management Protocol) snooping is essential for efficient sACN operation. When enabled, switches learn which ports need multicast traffic and only forward packets to those ports.

Switch Configuration Checklist

1. Enable IGMP Snooping: Usually found under multicast settings
2. Set IGMP Version: Use IGMPv2 for best compatibility
3. Configure IGMP Querier: One device must act as querier (often the switch itself)
4. Increase Multicast Group Limit: Default limits may be too low for many universes
5. Disable IGMP Fast Leave: Can cause brief dropouts during network changes

Unicast Fallback

If your network doesn't support multicast properly, many sACN implementations offer unicast mode. In unicast mode:

• Data is sent directly to specific IP addresses
• Works on any network (including consumer routers)
• Requires manual configuration of receiver addresses
• Less efficient for multiple receivers on the same universe

Universe Numbering in sACN

sACN universes are numbered from 1 to 63,999. Unlike Art-Net which uses a Net.Subnet.Universe scheme, sACN simply uses sequential universe numbers. This makes configuration straightforward:

• Universe 0 is reserved (not usable)
• Universes 1-63999 are available for DMX data
• Each universe contains 512 DMX channels (slots)
• Total capacity: 32,767,488 individual channels

Universe Planning Best Practices

Good universe organization makes systems easier to program, troubleshoot, and expand:

Strategy	Example	Benefits
Location-based	Universes 1-10: Stage Left Universes 11-20: Stage Right	Easy physical troubleshooting
Fixture-type based	Universes 1-5: Moving heads Universes 10-15: LED strips	Logical grouping for programming
Zone-based	Universes 100-199: Main stage Universes 200-299: FOH	Clear separation for large venues
Leave gaps	Start each zone at round numbers	Room for future expansion

Channel Addressing Within Universes

Each fixture needs a starting address within its universe. Follow these guidelines:

• Document everything: Maintain a patch sheet with fixture, universe, and address
• Group similar fixtures: Place identical fixtures consecutively for easier programming
• Leave buffer space: Don't pack fixtures too tightly in case you need to expand
• Consider fixture modes: Some fixtures have multiple DMX modes with different channel counts

One of sACN's most powerful features is its built-in priority system. Every sACN packet includes a priority value from 0 to 200, with 100 being the default. When multiple sources transmit to the same universe, receivers use priority to determine which source to follow.

How Priority Works

• Higher priority wins: A source with priority 150 overrides one with priority 100
• Equal priority: When priorities match, receivers typically use HTP (Highest Takes Precedence) merging
• Per-packet basis: Priority is evaluated for each incoming packet
• Timeout handling: If a high-priority source stops transmitting, lower priority sources take over

Common Priority Configurations

Scenario	Primary Source	Secondary Source
Main + Backup Console	Priority: 100 (default)	Priority: 50 (backup takes over if main fails)
Show + Architectural	Show console: 150	Architectural system: 100
Emergency Override	Normal operation: 100	Emergency system: 200
Audio-reactive + Manual	REACT audio system: 100	Manual override: 120

Source Identification

sACN packets include a human-readable source name (up to 64 characters). This helps identify sources during troubleshooting:

Network Architecture

For professional installations, consider these network design principles:

1. Dedicated Lighting Network: Use a separate VLAN or physical network for sACN traffic
2. Managed Switches: Enterprise-grade switches with proper IGMP support
3. Redundant Paths: For critical systems, implement redundant network paths
4. QoS Configuration: Prioritize sACN traffic (DSCP marking) on shared networks

Software & Hardware

Popular sACN-compatible solutions include:

• Consoles: ETC Eos, MA Lighting, Chamsys, Hog
• Software: QLC+, DMXIS, MagicQ, Resolume
• Nodes: ETC Net3 Gateway, Pathport, ENTTEC
• Audio-reactive: Compeller REACT (see below)

Testing & Troubleshooting

Essential tools for sACN diagnostics:

• sACN View: Free multiplatform sACN monitoring tool
• Wireshark: Network protocol analyzer with E1.31 dissector
• Network testers: Verify multicast routing and IGMP behavior
• DMX testers: Confirm output at node endpoints