Support For Allen & Heath systems - GigaAce and DX

Support For Allen & Heath systems - GigaAce and DX

Introduction

With default settings, it is not possible to have a Allen and Heath system run reliably on GigaCore switches. In a nutshell, it is because GigaAce and DX protocols rely on packet interval time to achieve clock synchronization. This means that, if a sufficient amount of data is inserted in this stream, the resulting offset can induce a delay between A&H packets sufficient to make the Consoles and stageboxes fal out of sync.
Due to the nature of the traffic and the mechanism, there is no way to completely prevent this. The packets transmitted by A&H devices don't have an ethertype and, therefore, can't be prioritized.
On a managed switch and specifically a Gigacore switch, there is always a small amount of traffic mechanism like IGMP snooping, LLDP to maintain awareness of endpoint and RLinkX to maintain awareness of the topology.
But we have been able to come up with settings that allow to use GigaCore switches with GigaAce and DX in most conditions.

Disclaimer

The following method to allow the use of Gigacore switches with A&H systems does not "fix" the issue. It makes it much less likely to happen.
This requires to disable some feature that are a central part of the Gigacore ecosystem. This can make some features restricted or inaccessible on the ports connected to A&H devices.
This method is to be used at the user's own risks. We can only provide limited support for this kind of systems.

Requirements

  1. Allen & Heath system must be on a dedicated VLan : the data generated by A&H systems broadcasts on all ports up to the full bandwidth of the port. Any other device connected to this VLan would flooded with this data and wouldn't be able to operate normally. For example, if you use the management network, the computer you use to configure the switch would most likely be overwhelmed by the traffic and would be able to access the web interface of the switch. This also means that, on a multiple switch system, the link between switches would have to be an ISL.
  2. The link between switches has to be 10Gb/s
  3. This method applies only the the new line of GigaCore switches. This means GigaCore 30i and newer models (GigaCore 20t, 18t, 16t, 16i 10i and 10t at the moment this article is being written).
  4. IGMP snooping must be disabled on the group
  5. RlinkX must be disabled on the ports connected to A&H devices
  6. LLDP must be disabled on the ports connected to A&H devices

Configuration


All the following steps are described for Gigacore firmware 1.2.3 and Araneo 1.7.1. Make sure to update your devices and software to follow this guide.

Topology and VLans

A&H systems have to be used on a dedicated VLan. In the case of multiple switches, ISL must be used between switches and the link between switch must be 10Gb/s.


Figure 1 : Example setup

Settings

The following settings need to be applied :
  1. Disable IGMP Snooping on the group used for the A&H system
  2. Disable RLinkX on the ports Connected to A&H devices
  3. Disable LLDP on ports connected to A&H devices
Here are the detailed steps to apply these settings

Disable IGMP snooping


In Araneo

  1. go to "Configure" > "Group/Trunks settings"
  2. Select the "Group" tab and then, select the group used for the A&H system
  3. In the "IGMP settings" section, untick "Snooping" and make sure that "Unknown flooding" is enabled and "Querier" is disabled (these last two steps should happen automatically).
  4. Click "Apply"




In the Web interface

For each switch:
  1. Access the web interface by entering the switch IP address in a browser
  2. Go to "Group / Trunk"
  3. Click on "Edit group"
  4. Scroll down to the "IGMP settings" section and untick "Snooping". "Querier" should be disabled automatically and "Unknown Flooding" should be enabled automatically.
  5. Click "Apply"





Disable RLinkX

In Araneo

  1. Go to "Configure" > "Port Settings"
  2. Select the "RLinkX" tab
  3. Select the ports connected to A&H devices by clicking on them in the graph. You can also do this by clicking on "Select ports of group" and then click on the group used for the A&H system
  4. Untick the box next to each selected port
  5. Click "Apply"


In the web interface

On each switch :
  1. Access the web interface by entering the switch IP address in a browser
  2. Click on "Port settings"
  3. In the "RlinkX" column, click on the RLinkX symbol for each port connected to a A&H device. The symbol should turn grey
  4. Click "Save"



Disabling LLDP

There is no GUI option to do this so this actions needs to be performed with the API. We're going to use the REST API client included in each new generation GigaCore switch to apply these settings. This need to be done on each switch manually.
For the purpose of this application, we only need to disable the LLDP transmission on ports connected to A&H devices.
  1. In a browser, enter the following command : http://<IP_OF_GIGACORE>/__rest-client.html
  2. At the top, set the method to "PUT" then, in the command field, enter "/api/lldp/port/<port_number>/tx and, in the payload field, enter "false"
  3. Click "send"
  4. In the bottom section you should see "200" in the first field indicating that the command was successfully applied, and the payload field should indicate "false" to confirm the current state
  5. Repeat this operation for each port connected to a A&H device


If you want to reverse the operation, repeat these steps but enter "true" instead of "false"

If you want to confirm the state of a port, set the mode to "GET" and enter the command "/api/lldp/port/<port_number>
You should a "200" response code and, in the response payload field, the state of all LLDP parameters for that port.



Backup

These settings can be saved to a profile on the switch if you want to recall them at a later time. You can also download the profile to your computer and save it as your GigaAce default.
Note that the LLDP settings can't be saved to a Araneo project. Also, deploying a Araneo project to a GigaCore network after applying this configuration will bring the LLDP settings back to default ( enabled )

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