what  the difference between it infrastructure and networks
Techopedia explains Network Infrastructure. Network infrastructure is typically part of the IT infrastructure found in most enterprise IT environments. The entire network infrastructure is interconnected, and can be used for internal communications, external communications or both.
Infrastructure refers to the underlying technology that your application runs on top of. Broadly speaking, infrastructure software refers to the software that enables network connectivity, server logic, databases, etc. A popular example of infrastructure is Amazon's cloud offerings, which allow developers to spin up computing, storage and other resources easily, and Amazon takes care of the hardware bit.