Linear scaling is a property of a system or application that lets it handle more work by adding more machines/server/nodes in a way proportional to the increase in work. Vertical scaling is when a network scales by adding more power (CPU, RAM) to an existing machine. In this case, resources added doesn’t always mean the performance increases in the same proportion. For example, a system that isn’t linearly scalable might only see a slight improvement in performance after a certain point, or it might show diminishing returns, where adding more resources only results in small improvements.