> For the complete documentation index, see [llms.txt](https://docs.lightact.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.lightact.com/layers-and-layouts/layer-layouts/nodes/node-action-flow.md).

# Node Action Flow

Action flow determines which nodes will be executed. You determine the action flow with Lifeline connections and every Lifeline starts with a Lifeline generator node.

## Default Lifeline Generator Nodes

<div align="left"><img src="/files/uYE8kIJX6oodvJDDhGn7" alt=""></div>

Default layer nodes: **Tick**, **On Begin,** or **On End**.

## Other Lifeline Generator Nodes

![Several nodes have New message lifeline output](/files/as6SJM2YlT9RU4q9ELNr)

There are a lot of nodes that have **New message** lifeline output. These nodes are primarily designed to receive messages from the network and work in conjunction with receiving *Device nodes*.

{% hint style="info" %}
**Good to know:** A good indicator that a layer is active, is blinking connection lines.
{% endhint %}