End-to-end protocol stacks in the Alcatel 1000 ADSL access network

The success of a new technology like ADSL (asymmetric digital subscriber line) largely depends on the ability to offer viable end-to-end network architectures and feasible operation/business plans. The Alcatel 1000 ADSL product supports a broadband remote access service model identical to the current narrowband remote access model although the building blocks are based on different components and technologies. Broadband services can be offered in exactly the same way as narrowband services with the same characteristics except for the bandwidth. A mixture of different end-to-end protocol stacks are necessary for a perfect integration with current and future platforms. The basic building blocks of the Alcatel 1000 ADSL are an access adapter (AA) at the central office or at a remote location, and an ADSL network termination (ANT) at the subscriber's premises (home, office). The access adapter interfaces to the backbone network (data backbone network, ATM network), and provides a transparent connection of the subscriber line to the PSTN network. The ANT interfaces with the subscriber's terminal using an ATMF (25 Mbit/s) or Ethernet connection, and guarantees a transparent connection to the subscriber telephone set (POTS/ISDN). At the heart of both the AA and the ANT is an ADSL modem that modulates and demodulates the digital data using sophisticated algorithms, so that it can be transmitted over the twisted pair. Splitters/filters are used to mix analogue telephone services or ISDN services and digital ADSL services, thereby allowing the traditional telephone services to coexist with new high speed services on the same twisted pair.