WAN basic questions
I am confused about some WAN concepts. I believe leased lines are private connections going through a service provider from one location to another. My understanding is that the lines may go through equipment that carries multiple other companies data, but the provider keeps them logically separate. Is that correct? What about MPLS? I believe its more concerned with upper layers, but when you have a company with multiple sites using it, what type of physical infrastructure is under it? Is it a physical infrastructure with a service provider that passes traffic for multiple customers or is each customer kept separate like leased lines? Even though its old, I was wondering the same for frame relay. I think of the internet as public connectivity and leased lines as private, but not sure about MPLS.