What is a "node license"?
When buying Corona Renderer licenses, you can choose how many workstation and render node licenses you need:
1 workstation license + 3 render node licenses, 1 workstation license + 5 render node licenses, or 1 workstation license + 10 render node licenses.
When Corona Renderer is activated ( 3ds Max | C4D ), it will register a license as either a workstation license (where you are working with the 3D viewport, creating materials and whole scenes), or as a render node license (where the computer is used only to render the image, usually when doing network rendering). Corona Renderer determines the license type automatically. You do not have to select which kind of license you want to use, and there are no separate activation methods for the workstation and render node licenses.
A node license is a license that may be used on a render node computer only (slave computer), where the host application (3ds Max, C4D, ...) is running in command line mode, with no user interface visible. This is used for example when rendering using Corona's Distributed Rendering in 3ds Max and/or Autodesk Backburner, or when using Team Render in Cinema 4D. It is the opposite of workstation license. The name "node license" is sometimes shortened to "N". For example, "1WS + 3N" means "1 workstation and 3 render node licenses".
All FairSaaS licenses are floating. This means that you can freely move a single node license between different computers. See: What is a "floating" license?
You do not need a 3ds Max of C4D license to render on a node PC. The host software just has to be installed. A trial license can be used for this, even if it's already expired.