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conferencing, distance learning and video-on-demand.
6. ADSL provides Telcos with the ability to offer a private, secure channel of
communications between the consumer and the service provider.
7. Data stream travels along the customers’ own line. It is quite unlike traditional
telephone and modem services sharing the line with others.
8. Using a customer’s dedicated line, ADSL transmission speeds are not
affected by other users going on line.
9. You can use telephone for normal conversations and high-speed conduit for
data, information, entertainment and more at the same time. It provides
enormous advantages both in office and at home.
2.2. VPI & VCI
The valid range for the VPI is 1 to 255. The VCI is 32 to 65535 since 1 to 31 is
reserved for local management of ATM traffic. Your Telecos should supply you with
these numbers.
ATM is a connection-oriented technology. It sets up virtual circuits over which end
systems communicate. The terminology for virtual circuits involves VC (virtual
channel) and VP (virtual path). VC is the logical connections between end stations
and VP is a bundle of VCs.
We can think of a VP as a cable that contains a bundle of wires. The cable
connects two points, and wires within the cable provide individual circuits between
the two points. In an ATM cell header, a VPI identifies a link formed by a virtual
path and a VCI identifies a channel within a virtual path. The VPI and VCI are
identified and correspond to termination points at ATM switched as shown below.
