sACN, RDM, EOS, Hog - Why don´t they like each other?

Dear ETC People.

I´d like to confirm / understand something. In our venue we´re running EOS streaming ACN to response gateways.
This week we have someone with a Hog4PC within our venue and he´s streaming ACN as well to control stuff.
For licensing he has two hoglets for 8 Universes summary and we´re basically arranging control by priorities.
Everything was good so far but at some point he wasn´t able to control stuff he should have.
Strange thing was that the sACN-Viewer showed him controlling the address but the device didn´t react.
EOS on the other hand didn´t change values in the sACN-Viewer as it had a lower priority but here the device reacted anyway.
We reseted the gateway that was putting out DMX and were fine.
Today we had the same problem on a universe where Hog and EOS have the same priority as there are dimmers only and checked with a DMX tester on the gateway and saw that it wasn´t outputting the hog ACN values.
Then we noticed that those two gateways had RDM activated for at least one port. We had networking troubles with one of them before when RDM was activated but an update to the most recent firmware fixed it.
Now we deactivated RDM for all gateways, rebooted the one giving us trouble and arer fine for the moment.
I hope we will be from now on.
Can anyone confirm if that is a known issue or if there is anything else I´m missing?
HogPC is 3.15, EOS is 3.0.1 and the response gateways are on the most recent firmware.



  • Hi ,

    Sorry that you are experiencing issues. I have some follow up questions for you:

    1. Are the gateways Response or Response Mk2?
    2. Which specific firmware are they running?
    3. How many total devices are on the network outputting sACN (including any backups, architectural systems, input gateways, etc.)?
    4. How many total universes are in use between all of the sources?
    5. What type of network switch is being used in the venue to connect the devices?
      1. Does this network switch have IGMP snooping enabled?
      2. Does this network have an IGMP querier defined?
    6. Does just disabling RDM without the reboot correct the issue?
  • Hej,
    thank you for the quick response. I´ll try to answer your questions as good as I can but I´m not in theater now and won´t be before saturday but let´s see...

    1. Gateways are Response MK2
    2. Software has to be as I updated them in december and it was the most recent one back then.
    3. Right now there is an EOS TI (Main), IonXE (Backup), Laptop with Hog4PC, Paradigm (2 x Paradigm, 1 x Conductor) and for a short while we had a Nomad Laptop online as a Client. I expect only the TI, Paradigm and Hog to actually output as backup and client won´t do that in that scenario right? In sACN-viewer those three are the only devices I can see.
    4. The Hog has 7 universes patched and 8 mapped. The paradigm has 4. The EOS has 12 sACN Universes in use (1-12) and universes 101-103 patched for an Arkaos Media-Server sending ArtNet.
    Probably there are some leftovers we never cleaned up on other universes but those are just virtual and there are no nodes involved.
    5. The switches are HPE OfficeConnect 1820 Series - J9983A
    6. To be honest: I never heard about that before. I just googled:
    a. and the manual of those switches tells that it´s available but I can´t tell what the configuration is. The company that did the installation just told us that those are unmanaged switches and we were happy so far.
    As said I won´t be back in theatre before the weekend but if we keep having troubles I´m shure my colleagues can check that.
    b. is more or less the same thing as a. ...
    6. I can´t tell. We did it mid rehearsal and didn´t sort that out one by one. Actually we rebooted first and I got the idea that RDM could be the reason for our troubles afterwards and deactivated it then.

    I hope this additional info helps a bit.
    Mainly I hope we won´t have any troubles from now on with RDM off but would like to know if that really causes it.

    Thank you so far!

  • Thanks for the information you were able to provide, that's quite helpful!

    2. You could try updating to version as there were some bugs fixed around RDM that may or may not impact you.

    3. Yes the Eos backups and clients as well as PCCS and Conductor aren't actually outputting so only the primary output devices shown in sACNview would be the ones we're concerned about.

    4 & 6.   7+4+12+3 = 26 Universes/sources of data on the network in this case as IGMP snooping is off by default in the 1820 series switches (according to this configuration guide) so multicast traffic is likely being handled more like broadcast traffic. Depending on if you have other gateways that are set to act as an input, your source count might increase as well. This can mean that some devices, including possibly your gateways, could have trouble keeping up with the traffic and determining which sources to keep and ignore. (Disabling RDM would have reduced the traffic on the network to help with this issue).

    If possible, I would encourage you to consider enabling IGMP snooping on the switch to make the traffic on the network more efficient. However, the switch's manual is silent on an IGMP querier (the device that maintains the list of multicast addresses in use) so you may wish to investigate that further prior to making a sweeping network change if you have more than one switch. 

  • Thx!

    My colleagues are studiing the settings for those hp switches. We have almost a dozend of them in our installation so as you say we have to learn about the igmp querier.

    I'm still hoping that for this production we'll be good without any further changes but to know how to handle bigger traffic would be good anyway.

    Just as additional info:

    ArtNet shouldn't affect the traffic for those nodes as they are only recieving sACN. For one of the network ports on EOS we have only sACN enabled and for the other one only ArtNet.

    In our setup there are no nodes with port konfigurations for DMX-in.

    Thank you so far!

    Cheers Paul

  • Hi there,

    did the setup worked in the end? And did you edited something?

    An other question to : Do you think that the Per-Channel Priority could intervene in a setting like that?

    I know that Hog4 can toggle Per-Channel Priority on and of. But i never checked it.

    Maybe i give it a try some day.

    Maybe   can again tell the detailed priority settings that where made.

  • Eos has per-address (per-channel) priority always on. Hog 4 can enable/disable/adjust priorities as a setting in the console setup but it is off by default. It is possible that the combination of per-address and per-universe settings were interacting negatively, but the bigger issue is likely the flood of traffic going everywhere on the network as broadcast without IGMP snooping enabled.

    ArtNet is a broadcast protocol so it will send out data and everyone on the network gets it and then decides to do something with it or drop the packet. sACN is a multicast protocol so that only those who are interested in the specific universes will get the data if the switch has IGMP snooping enabled to know which end-devices are interested in which universes. Without that enabled, again every device will get all of the universes of information and it will be up to the end device to determine if it is interested in that data or not.

    Receiving packets of information that you aren't interested in requires processing time and power to determine what it is and that you're not interested which can negatively affect response and operations if there is more time spent ignoring packets than using them.

  • So in that case, while having ArtNet and sACN on the same Network, it could (but may wouldn't) be draining more Traffic and Ressources because of ArtNet most likely is Broadcast?

  • Yes, depending on how much traffic is there and any other settings in the switch, it is possible that a large amount of ArtNet could affect devices in the same subnet, even with IGMP snooping enabled so they are only getting the sACN they are interested in. It's all about balance.

  • I see. Thanks a lot for the compressed small information jet.

    I think i do need to get some more schooling with thinks like that.

    But i do have a good feeling on my way since you made it quite understandable.

    Thank you very much.

  • I recommend checking out our Network Design guides (available here: Network Design - Electronic Theatre Controls Inc) for more information too.