Studying the WAN lines types, am I right regarding the statements below, or if not, could you correct me please:
- A real leased line, could be performed with TDM on a line with for example SDH, TDH or SONET with a CSU/DSU on the customer site (a layer 1 leased line?)
- A leased circuit could be done with a ATM CPE on the customer site, typically for a point to point connection needs (a layer 2 circuit?)
- A leased circuit could be done with a MPLS tunnel with what we call Provider router, and Customer Router on the customer site, for any to any connection type
On the case of ATM and MPLS, as far I understood it's like "logical" leased line, and how the ISP reserve the bandwidth for the customer ? And what could be the layer 1 protocol ? SDH, SONET ? Other ?
And finally, generally, what is the most frequent technics implemented, leased line or leased circuit ?
Many thanks, all these notions are not very clear for me.