Yesterday I posted about DMX-512 dimmer. DMX-512 is a lighting industry standard way of controlling lighting equipment.DMX-512 allows for one controller (like a lighting desk or computer) to control many lights from many manufacturers. DMX-512 fundamentally provides 512 channels of 8-bit resolution (0-255) level control(which constitue a DMX ‘universe’) using serial RS-485 communications at 250 kbps/s data speed. DMX-512. DMX-512 was created in 1986, with subsequent revisions in 1990 leading to USITT DMX512/1990, and updated version“E1.11 – 2008, USITT DMX512-A” was approved by the American National Standards Institute (ANSI) in November 2004
Nowadays when there is a trend that all the communications is converging to use Ethernet, the has been several task forces in converting lighting control to Ethernet. One standard to this direction is ESTA’s BSR E1.17, the “Architecture for Control Networks” protocol (ACN) developed by the live entertainment industry for control of pretty much anything. It is an entirely new protocol.
There are also work going on somewhat simpler approach where you you combine DMX-512 devices and transport the communications over Ethernet where that suits best. For example there are situations where it makes a lot of sense to use computer to send control data to Ethernet network, and at location near the actual lighting equipment convert it to DMX-512 signal. There are several competing protocols for this:Art-Net, Shownet and E1.31 (also called Streaming ACN). There are Art-Net and sACN compatible software, both free & commercial. (FreeStyler, Madrix, Jinx, LoR(E1.31) ……….)
Art-Net is a communications protocol for transmitting the DMX512-A lighting control protocol and Remote Device management (RDM) protocol over the User Datagram Protocol (UDP) of the Internet Protocol suite. It is a trademark of and copyright by Artistic Licence Holdings Ltd., which released the protocol specification into public domain and allows the protocol to be used subject to attribution, but without royalty. Art-Net uses a simple UDP based packet structure designed to provide efficient and low overhead data flow. Art-Net was created by Artistic Licence to overcome the channel restriction of DMX while still utilizing its structure: allows multiple DMX universes to be transported over a single Cat5 cable using ethernet technology. Art-Net I was implemented on 10BaseT network and it uses broadcast. Art-Net II was released in 2006 and it can also use unicast communications. The protocol specification is available for download from the Artistic Licence web site.
E1.31 (also called Streaming ACN) is a protocol for sending DMX512 data over the ACN (E1.17) family of protocols. Streaming ACN (sACN) is a standard protocol developed by ESTA to efficiently transport DMX universes over the network. It is comparable to ArtNET in many aspects. One nice thing is the multicast option allowing very easy configuration. sACN is a popular protocol to control large number of RGB LEDs. E1.31 is expected to become the new standard for transporting DMX over IP, replacing other protocols such as ArtNet and Shownet.
Interesting looking projects related to Art-Net:
ArtNet arduino set v3.1 has implementation of ArtNet receiver and sender working
chris‘s library also implements receiving DMX, working with EtherCard (i.e. the ENC28J60).
Nat‘s library can receive multiple universes and has examples for the NeoPixel library and OctoWS811 libraries. It works with the standard Ethernet library
SmartShow Artnet sACN to 2 DMX universe WS2812 Neopixel Driver – Arduino Nano video
Interesting looking projects related to sACN:
ESPixelStick – An E1.31 WiFi Pixel Controller is a pixel driver motherboard for the ESP8266 ESP-01 WiFi module that supports WS2811 / WS2812 pixels
SmartShow Artnet sACN to 2 DMX universe WS2812 Neopixel Driver – Arduino Nano video
14 Comments
Tomi Engdahl says:
sACNView
sACNView, a tool for sending and receiving the Streaming ACN control protocol
http://docsteer.github.io/sacnview/
Tomi Engdahl says:
Art-Net to DMX512 with ESP8266
https://robertoostenveld.nl/art-net-to-dmx512-with-esp8266/
Tomi Engdahl says:
Timing and jitter in DMX512 signals
https://robertoostenveld.nl/tag/dmx512/
Tomi Engdahl says:
PoE Powers Christmas Lights, But Opens Up So Much More
https://hackaday.com/2019/12/31/poe-powers-christmas-lights-but-opens-up-so-much-more/
The decoration is powered exclusively from power-over-Ethernet, with a PIC microcontroller translating Art-Net DMX-over-Ethernet packets into commands for the LED string. The control board is designed from the ground up and includes all the PoE circuitry
Tomi Engdahl says:
https://bikerglen.com/blog/ethernet-powered-pixels/
Tom78 says:
It is really interesting to visit such websites
Tomi Engdahl says:
What are Art-Net and sACN?
https://www.learnstagelighting.com/art-net-sacn/
used to be that we just used simple DMX cable out of our console to our lights to control everything. Today, it’s becoming more and more common to use Art-Net and sACN – common forms of networked DMX – to control our lights.
If you’re not familiar with these protocols yet, watch the video below to get the basics.
https://artisticlicenceintegration.com/technology-brief/technology-resource/sacn-and-art-net/
sACN
sACN or Streaming-ACN is the colloquial name for the ANSI E1.31-2016 standard. This is primarily designed to move zero start code DMX data over a network in a way that is compatible with the full ACN standard (ANSI E1.17-2010).
Art-Net is a public domain network protocol developed by Artistic Licence. It is designed to transport DMX512 and RDM packets over a network.
RDMnet or Streaming-RDM is the colloquial name for ANSI BSR E1.33 (Board of Standards Review). This will become a standard that allows RDM packets to be streamed over a network.
In functionality terms, the combination of sACN and RDMnet provide the same functionality as Art-Net.
sACN and Art-Net are both based on UDP data and so can coexist on the same network.
The ArtDmx packet within Art-Net is used to achieve the same results as the sACN protocol – to move DMX512 packets over a network. While both can handle non-zero start code packets – the primary purpose is zero-start code data – lighting levels.
Both protocols achieve this by putting a packet wrapper around a frame of up to 512 channel levels. The sACN wrapper is setup in such a way that it can be understood by a full ACN product. This does mean that the wrapper is significantly larger than it would otherwise need to be, but given modern bandwidths this is not really a problem.
sACN can carry up to 63,999 universes while Art-Net can carry 32,768.
Tomi Engdahl says:
ESP8266 Art-Net DMX to WS2812 © GPL3+
Control WS2812 LED strings with Art-Net DMX over WiFi.
https://create.arduino.cc/projecthub/jackguy/esp8266-art-net-dmx-to-ws2812-41c5fa
Tomi Engdahl says:
https://www.chromateq.com/44-chromateq-led-player-software.htm
Led Player is also the ideal DMX512 software for all Architectural applications thanks to its ability to write a show in to the stand alone memory of the Chromateq devices and play back sequences without computer.
• User firendly and effective Live Board mode to play and trigger
• Compatibility with 32/64 bit systems (Windows, Mac Os X, Linux)
• Free, downloadable updates
• Can modify the DMX signal speed and allocated DMX universes
• Includes a smart-phone communication to command the live board
Tomi Engdahl says:
https://www.lightjams.com/
What is it? Lightjams is a software for interactive DMX lighting. It’s all about giving you the power to generate unique effects based on many types of live signals – MIDI, OSC, DMX, music, video, time, etc.
Tomi Engdahl says:
Mod for the game Satisfactory by Coffee Stain Studios to control lights with ArtNet.
https://github.com/moritz-h/satisfactory-lightcontrol
Tomi Engdahl says:
ArtNet Not Going Through? Your Switch Might Be Protecting You
https://hackaday.com/2023/02/12/artnet-not-going-through-your-switch-might-be-protecting-you/
Cool technology often comes at a cost, and it’s not always that this cost is justified. For instance, [Rainfay] tells us about how the the ArtNet protocol’s odd design choices are causing incompatibility with certain Ethernet switches. ArtNet is a protocol for lighting control over DMX-512 – simply put, it allows you to blink a whole ton of LEDs, even literally. Unlike DMX-512 which can use different physical mediums, ArtNet uses Ethernet, taking form of the usual kind of network packets – and it does seem to do a great job about that, if it weren’t for this one thing.
For some reason, ArtNet connections are required to use the same destination and source port – unlike the usual network traffic, where the destination port is protocol-dependent and the source port is randomized. This behaviour violates RFCs, and not just in an abstract manner – such behaviour is indicative of certain kinds of attacks, that switches on the smart side are able and are supposed to prevent. As a result, ArtNet traffic actually triggers some protections on switches at the fancier end, specifically, so-called BLAT protection.
In short, if your ArtNet stream is mysteriously not going through and your switch is on the fancier side, [Rainfay] says you might need to disable some security mechanisms. Sadly, as she points out, this problem isn’t even a direct consequence of some inherent property of ArtNet, but merely a consequence of a bizarre design choice.
ArtNet is not conforming to RFCs
https://www.fayebell.name/?p=520
For all the Network Techs out there. I have a Interesting one, on reddit there was a post about a L2 switch killing the port when ArtNet was sent over it. Using my Network experience, I pulled the devices manual, a the Device in question is a GSD-1002M L2/L4 switch. I wrote up how I would configure it. Long story short it was the DOS protection on this switch. I dug in deeper, made this nice RCA for this issue,
The highlighted settings are the items of interest the UDP and TCP BLAT settings.
What is a Blat Attack – These switch result from sending a specially crafted packet to a machine where the source host port is the same as the destination host port. The system attempts to reply to itself, resulting in system lockup.
This attack could be compared to setting up a mic IN FRONT of your Main PA 1″ Away from the speaker. Then Turning it on full blast.
Looking at RFC6056
Recommendations for Transport-Protocol Port Randomization
Looking at RFC1948
Defending Against Sequence Number Attacks from May 1996
In summary “source port == destination port” is a bad practice.
This Bug has been fixed for a long time in the Linux Kernel networking subsystem to avoid this issue
So in closing,
source port == dest port. Is triggering the Blat DOS detection.
Now lets look at the Protocol spec.,
It states that the programmer must use, source port of 6454 to contact the destination listing port 6454 of the server.
That is Not conforming to Multiple RFCs and is using a bad practice.
Work around Disable BLAT protection.
Root Cause ArtNet protocol says to use the same source port(client) as the destination port (server). is causing the issue.
Tomi Engdahl says:
https://pro.arkaos.com/kling-net
KlingNet3 is a new flexible, cloud-compatible, lighting and visual control protocol for the future developed by InMusic Brand’s ArKaos for the entertainment industry.
It takes flexibility, user-friendliness, feedback, and ultimate control to next-gen levels.
Tomi Engdahl says:
https://dmxnest.com/?fbclid=IwZXh0bgNhZW0CMTEAAR38DViqYVCkpw5jFrm0PGny82il4c1fwHwVZnc7xE3vjVTq8zovnY4wmzg_aem_AS1ndbkv0uAI2wKbKRYN4SOh454pV29h9lrelWP5jy10Q3ZWCXdsA7Vczzq81eYsm_rZsf6iCwOCCd7–WaDsUpU