Node Locked
The Node Locked license grants you the software access in a single computer. The license file is associated to an unique identifier - a MAC address, for instance - which will give you access to the program. This kind of license is ideal for engineers and companies that develop its projects in a single or few workstations, therefore don’t need a server.
You also have the option to use a Dongle. This way, instead of being associated with a single machine, the license is linked to a Hardkey (the Dongle). The major benefit of the Dongle is the mobility that it gives the project planner that is able to execute the license in different workstations with the software installed and properly configured.
Floating
The Floating license “floats” in the server, giving access to the software in different workstations, not only a specific one. It stays in a server which any computer that has access to it can use it, as longs as it doesn’t exceeds the number of licenses purchased. For instance, if you have three licenses of a specific software, you’ll be able to use it in three different machines. The advantage of this kind of license is the versatility that it provides the project planner, which can use the software as soon as it’s released from another workstation.