C-Com IPAM-1600s Series, Руководство пользователя, Страница: 13 / 148

Introduction
UM1600-2-A 2002
11
What’s the difference between ATM based DSLAM
and IP based DSLAM-IPAM-1600s?
Fig 0-1 & Fig 0-2 display the differences between traditional ATM-based DSLAM
and IPAM-1600s in PPPoE application sample.
Fig 0-1 PPPoE application in Traditional ATM-based ADSL Network
As Fig 0-1 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, Offices, ..),
at there the ATM cells and PPPoE frames is resolved by the Broadband Access
Server, and the user application information is serviced.