# LightNet overview

## What is LightNet?

LightNet is LightAct's multi-server functionality. It allows you to:

* detect other machines with LightAct on the network,
* determine the role of each machine,
* set up multiple LightNet clusters of machines,
* set up frame syncing,
* transfer project files between all the machines within a single cluster, and
* establish real-time editing across the entire cluster.

{% hint style="info" %}
**Good to know:** we sometimes use the word machine and sometimes a server. In the context of LightAct and LightNet, it's essentially the same thing.
{% endhint %}

## Machine roles

<figure><img src="/files/bsKhLvPmKAI340zPoc7y" alt=""><figcaption></figcaption></figure>

LightAct uses the following naming of machine roles:

* **Primary**: this is the controlling server in the cluster. There can be only one in a cluster. In other solutions this role is called *Director, Host* or *Master*.
* **Secondary**: these are the servers outputting content. There can be many of them. In other solutions, these are sometimes called *Actors, Clients, Playout machines* or *Slaves*.
* **Editor**: these are the machines that don't output anything. Very often these are just laptops connected to the cluster that the operators use to edit the show.
* **Backup**: these machines are on stand-by during the show and are ready to replace the designated servers that might fail. In other solutions they are sometimes called Understudy.

{% hint style="info" %}
**Good to know**: in smaller projects where Secondary servers are not required, there is often just one *Primary* which is outputting the content and one *Backup*. Of course, you can have as many *Editors* as you want.
{% endhint %}

{% hint style="warning" %}
If there are *Primary* and *Secondaries* in a cluster and *Primary* is outputting the content as well, the outputs between *Primary* and *Secondaries* might not be in sync.
{% endhint %}

{% hint style="info" %}
**Good to know**: we often refer to *Secondary*, *Editor* and *Backup* machines as non-Primary machines.
{% endhint %}

{% hint style="warning" %}
All the servers that are outputting content need to have their outputs genlocked. Also see [Output Management ](/output-setup/output-management.md)chapter.
{% endhint %}

### Technical specs of machine roles

In a LightNet cluster with *Primary*, *Secondaries*, *Backups* or *Editors*, there are a few considerations when it comes to the technical specifications of each machine role.

{% hint style="info" %}
**Good to know**: More information about our servers can be found on [Hardware Overview page](https://lightact.com/hardware/).
{% endhint %}

#### Specs of servers that are outputting content

The machine roles that are outputting content in a LightNet cluster are:

* **Primary with outputs**: if you are using a cluster without secondaries, then Primary will be outputting the content.
* **Secondaries** almost always output content.
* **Backups** almost always need to be able to replace a Primary or any Secondary.

If a server is outputting the content (or needs to be able to), then what will determine the server's specifications are:

* type of the content,
* the number of pixels being pushed out (usually counted by the number of outputs) and
* the Expansion Modules that are required.

{% hint style="info" %}
**Good to know**: in [LightAct Datasheets](https://lightact.com/uploads/marketing/LightActDatasheets-latest-web.pdf), there is a useful decision tree that will help you find the best server for your project.
{% endhint %}

#### Specs of servers that are not outputting any content

In a LightNet cluster are a few cases where a server will not be outputting any content:

* **Primary without outputs**: in a LightNet cluster with *Primary* and *Secondaries*, it is often the case that the *Primary* server does not output any content. In this case, users usually use either a **Unit v** or a **Double v** (of the latest generation) as the *Primary*.
* **Editors** never output any content. In most cases this can be a laptop that fulfills [recommended system requirements](/preparing-your-hardware-for-lightact/getting-your-hardware-ready-to-run-lightact.md).

{% hint style="info" %}
**Good to know**: for *Primary* servers with no outputs we offer a **No Outputs Ultimate license**. More information can be found in [License FAQ ](https://lightact.com/faq-licensing/)page.
{% endhint %}

### License considerations

In a LightNet cluster all the machines need to have the same license tier with 2 exceptions:

1. You can combine servers with **Live** and **Ultimate** licenses in the same cluster.
2. **Editor** machines can use the **Creator** license.

{% hint style="info" %}
**Good to know**: more information about License tiers is available [here](https://lightact.com/licenses/).
{% endhint %}

{% hint style="warning" %}
Please note, the only license tier that enables *Secondary* LightNet role is the **Ultimate** license tier.
{% endhint %}

{% hint style="info" %}
**Good to know**: in complex LightNet setups, we recommend to use machines with the **Ultimate** license tier.

However, if you want to combine machines with *Live* and *Ultimate* license tiers in a LightNet cluster, you can use:

* machines with *Ultimate* licenses as the *Secondaries* and *Backups*
* machine with *Live* license as the *Primary*
  {% endhint %}

{% hint style="warning" %}
Please note, machines with the **Live** license tier can also be a *Backup*, but in this case it will only be able to replace a *Primary*.
{% endhint %}


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