Planet Technology IP DSLAM IDL-4801 - Manual (Page 706)

IDL series User Guide 706
Appendix D --- What’s IP DSLAM
DSLAM and IP DSLAM in PPPoE application sample.
As above Figure displays, in traditional ATM-based ADSL network, the user application
information is encapsulated by ADSL CPE into ATM cells in pre-defined VC (Virtual
Channel, PVC), and then upstream the ATM cells to DSLAM via ADSL link. (In this example,
the user information (PPPoE encapsulated) is encapsulated by ATU-R using RFC-1483
Bridge-mode encapsulation format.).
All the ATM cells belong to the specified VC is concentrated by the DSLAM, and switched in
the ATM network clouds, to the defined destination (ISPs or Offices), at there the ATM cells
and PPPoE frames is resolved by the Broadband Access Server, and the user application
information is serviced.