I don't know how can I explain these things ,If any one not comfort with these things just ignore this
you are little bit correct machan, any kind of ADSL/DSL network has two segment core(main) network and peripheral network (where end user locate). core network is very often based on IP over ATM (IP for network layer ,ATM for datalink Layer) . peripheral network has several options for its datalink layer, most common one is PPPOE