E1.31 (sACN) Plugin

Overview

The E1.31 plugin implements the ANSI E1.31 (Streaming ACN) protocol for transmitting and receiving DMX512 data over Ethernet networks. E1.31 is a standardized protocol developed by ESTA (Entertainment Services and Technology Association) as an open alternative to Art-Net.

The plugin name as reported by QLC+ is “E1.31”

Capabilities

The E1.31 plugin supports:

Output - Send DMX data over network
Input - Receive DMX data from network sources
Infinite - Unlimited universes

Protocol Specifications

Protocol: ANSI E1.31 (Streaming ACN)
Port: 5568 (UDP, default)
Universe Range: 1-63999
Channels per Universe: 512
Multicast: Supported (239.255.x.x)
Unicast: Supported

#define E131_DEFAULT_PORT 5568

Network Interface Structure

The plugin creates a controller for each network interface:

typedef struct _eio
{
    QNetworkInterface iface;       // Network interface
    QNetworkAddressEntry address;  // IP address configuration  
    E131Controller* controller;    // Controller instance
} E131IO;

Configuration

Network Interface Detection

The plugin automatically detects all available network interfaces at startup:

#define SETTINGS_IFACE_WAIT_TIME "E131Plugin/ifacewait"

Custom Parameters

E1.31 supports extensive configuration through custom parameters:

#define E131_MULTICAST "multicast"         // Enable multicast mode
#define E131_MCASTIP "mcastIP"            // Multicast IP address
#define E131_MCASTFULLIP "mcastFullIP"    // Full multicast IP (no calculation)
#define E131_UCASTIP "ucastIP"            // Unicast IP address
#define E131_UCASTPORT "ucastPort"        // Unicast port
#define E131_UNIVERSE "universe"          // E1.31 universe number
#define E131_TRANSMITMODE "transmitMode"  // Full or Partial
#define E131_PRIORITY "priority"          // Packet priority (0-200)

Setting Parameters

void setParameter(quint32 universe, quint32 line,
                  Capability type, QString name, QVariant value);

Multicast vs Unicast

E1.31 supports both multicast and unicast transmission:

Multicast
Unicast

Multicast Mode

Automatically calculates multicast address from universe number:Formula: 239.255.{universe >> 8}.{universe & 0xFF}Examples:

Universe 1 → 239.255.0.1
Universe 256 → 239.255.1.0
Universe 512 → 239.255.2.0

Advantages:

Efficient for multiple receivers
Devices join specific multicast groups
Reduced network traffic

Configuration:

setParameter(universe, line, Output, "multicast", true);
setParameter(universe, line, Output, "universe", 1);

Unicast Mode

Send directly to a specific IP address:Configuration:

setParameter(universe, line, Output, "multicast", false);
setParameter(universe, line, Output, "ucastIP", "192.168.1.100");
setParameter(universe, line, Output, "ucastPort", 5568);
setParameter(universe, line, Output, "universe", 1);

Advantages:

Point-to-point communication
Easier firewall configuration
Works across routed networks

Use cases:

Single receiver
Crossing network boundaries
When multicast is blocked

Universe Configuration

E1.31 universe structure:

typedef struct _uinfo
{
    bool inputMulticast;              // Input uses multicast
    QHostAddress inputMcastAddress;   // Input multicast address
    quint16 inputUcastPort;          // Input unicast port
    quint16 inputUniverse;           // E1.31 universe number for input
    QSharedPointer<QUdpSocket> inputSocket; // Input socket
    
    bool outputMulticast;            // Output uses multicast  
    QHostAddress outputMcastAddress; // Output multicast address
    QHostAddress outputUcastAddress; // Output unicast address
    quint16 outputUcastPort;        // Output unicast port
    quint16 outputUniverse;         // E1.31 universe number for output
    int outputTransmissionMode;     // Full or Partial
    int outputPriority;             // Priority (0-200, default 100)
    
    int type;                       // Input, Output, or both
} UniverseInfo;

Output Configuration

Opening an Output

bool openOutput(quint32 output, quint32 universe);

Transmission Modes

enum TransmissionMode { 
    Full,     // Always send full 512-channel universe
    Partial   // Send only up to highest non-zero channel
};

Full Mode

Sends all 512 channels every time.Best for: Maximum compatibility, devices requiring full universes

Partial Mode

Sends only channels up to the highest with data.Best for: Bandwidth optimization, fewer channels in use

Sending Data

void writeUniverse(quint32 universe, quint32 output,
                   const QByteArray& data, bool dataChanged);

The plugin:

Retrieves the E1.31 controller for the output line
Calls sendDmx() with universe and data
Controller packetizes according to E1.31 specification
Transmits via UDP (multicast or unicast)

Priority

E1.31 supports priority levels (0-200, default 100):

setParameter(universe, line, Output, "priority", 120);

Higher priority sources take precedence when multiple sources send to the same universe.

Priority is useful when you have backup systems or multiple controllers that might send to the same universe.

Input Configuration

Opening an Input

bool openInput(quint32 input, quint32 universe);

Multicast Input

For multicast input:

Plugin joins the multicast group for the specified universe
Listens on the multicast address
Processes E1.31 packets matching the universe number

// Example: Listen for universe 1 on 239.255.0.1
setParameter(universe, line, Input, "multicast", true);
setParameter(universe, line, Input, "universe", 1);

Unicast Input

For unicast input:

Plugin listens on specified port (default 5568)
Accepts packets from any sender
Filters by universe number

setParameter(universe, line, Input, "multicast", false);
setParameter(universe, line, Input, "ucastPort", 5568);
setParameter(universe, line, Input, "universe", 1);

Receiving Data

When E1.31 packets arrive:

UDP socket receives the datagram
Controller validates E1.31 packet structure
Extracts universe number and DMX data
Emits valueChanged() for changed channels

signal void valueChanged(quint32 universe, quint32 input,
                        quint32 channel, uchar value);

Network Configuration

Multicast Configuration

Enable multicast on your network

Ensure switches and routers support IGMP (Internet Group Management Protocol)

Configure IGMP snooping

Prevents multicast flooding by intelligently forwarding to interested parties only

Set appropriate TTL

Multicast TTL (Time To Live) determines how far packets can travel across routers

Join multicast groups

Receiving devices automatically join the appropriate 239.255.x.x address

Firewall Configuration

Allow E1.31 traffic:

# Linux (iptables)
sudo iptables -A INPUT -p udp --dport 5568 -j ACCEPT
sudo iptables -A OUTPUT -p udp --sport 5568 -j ACCEPT

# Linux (firewalld)  
sudo firewall-cmd --permanent --add-port=5568/udp
sudo firewall-cmd --reload

Allow multicast:

# Linux - allow multicast group joins
sudo iptables -A INPUT -d 239.255.0.0/16 -j ACCEPT
sudo iptables -A OUTPUT -d 239.255.0.0/16 -j ACCEPT

Network Interface Configuration

Recommended setup:

Interface: eth1
IP Address: 192.168.1.10
Subnet Mask: 255.255.255.0
Gateway: (none for dedicated E1.31 network)

For multicast to work properly, your network switch must support IGMP snooping. Without it, multicast packets may be flooded to all ports or blocked entirely.

E1.31 vs Art-Net

Feature	E1.31	Art-Net
Standard	ANSI/ESTA	Proprietary (open)
Port	5568	6454
Multicast	Built-in (239.255.x.x)	Optional
Universe Range	1-63999	0-32767
Priority	Yes (0-200)	No
Sync	Built-in sync packets	ArtSync packets
Discovery	No	ArtPoll/ArtPollReply

E1.31 is preferred for new installations due to being an open ANSI standard. Art-Net has wider legacy device support.

Performance Optimization

Bandwidth Optimization

Use Partial transmission mode when possible
Use multicast instead of multiple unicast streams
Reduce refresh rate for static scenes
Patch only required universes

Multicast Best Practices

Use IGMP v3 for better multicast management
Limit multicast scope with appropriate TTL values
Monitor multicast traffic to detect flooding
Configure switch priorities for E1.31 traffic

Multiple Network Interfaces

Distribute universes across multiple NICs:

NIC 1: Universes 1-16 → 239.255.0.1 - 239.255.0.16
NIC 2: Universes 17-32 → 239.255.0.17 - 239.255.0.32

This load balances across physical interfaces.

Troubleshooting

No Output

Check multicast settings

Verify multicast is enabled on network switches and receiving devices are joining the correct multicast group

Verify universe numbers

E1.31 universes must match between sender and receiver (1-63999)

Test with unicast first

Unicast is simpler to troubleshoot than multicast - verify basic connectivity first

Check firewall

Ensure UDP port 5568 is open and multicast addresses (239.255.x.x) are allowed

No Input

Verify the sender is using the correct universe number
Check that multicast group is joined (for multicast input)
Use Wireshark to capture and verify E1.31 packets
Confirm port numbers match (default 5568)

Multicast Not Working

Verify IGMP support

Check if your switch supports IGMP snooping

Enable IGMP snooping

Enable on all switches in the path

Check multicast routing

Ensure multicast is routed correctly between VLANs (if applicable)

Test with broadcast

Temporarily use unicast/broadcast to isolate the issue

Packet Analysis with Wireshark

Filter for E1.31 traffic:

udp.port == 5568

Filter for specific multicast address:

ip.dst == 239.255.0.1 && udp.port == 5568

Protocol Details

For full E1.31 protocol specifications:

ANSI E1.31 Standard (ESTA)
Search for “E1.31” in the published documents list

Art-Net

Alternative Ethernet DMX protocol

OSC

Open Sound Control protocol

Plugin Overview

Learn about the plugin architecture

Supported Protocols

Hardware Support

​Overview

​Capabilities

​Protocol Specifications

​Network Interface Structure

​Configuration

​Network Interface Detection

​Custom Parameters

​Setting Parameters

​Multicast vs Unicast

​Multicast Mode

​Unicast Mode

​Universe Configuration

​Output Configuration

​Opening an Output

​Transmission Modes

Full Mode

Partial Mode

​Sending Data

​Priority

​Input Configuration

​Opening an Input

​Multicast Input

​Unicast Input

​Receiving Data

​Network Configuration

​Multicast Configuration

​Firewall Configuration

​Network Interface Configuration

​E1.31 vs Art-Net

​Performance Optimization

​Bandwidth Optimization

​Multicast Best Practices

​Multiple Network Interfaces

​Troubleshooting

​No Output

​No Input

​Multicast Not Working

​Packet Analysis with Wireshark

​Protocol Details

​Related Pages

Art-Net

OSC

Plugin Overview

Build docs developers (and LLMs) love

Overview

Capabilities

Protocol Specifications

Network Interface Structure

Configuration

Network Interface Detection

Custom Parameters

Setting Parameters

Multicast vs Unicast

Multicast Mode

Unicast Mode

Universe Configuration

Output Configuration

Opening an Output

Transmission Modes

Sending Data

Priority

Input Configuration

Opening an Input

Multicast Input

Unicast Input

Receiving Data

Network Configuration

Multicast Configuration

Firewall Configuration

Network Interface Configuration

E1.31 vs Art-Net

Performance Optimization

Bandwidth Optimization

Multicast Best Practices

Multiple Network Interfaces

Troubleshooting

No Output

No Input

Multicast Not Working

Packet Analysis with Wireshark

Protocol Details

Related Pages