CCNA Cisco Certified Network Associate Study Guide - FTP Server

Integrated Services Digital Network (ISDN) 505
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Integrated Services Digital Network (ISDN)
Integrated Services Digital Network (ISDN) is a digital service designed
to run over existing telephone networks. ISDN can support both data and
voice—a telecommuter’s dream. But ISDN applications require bandwidth.
Typical ISDN applications and implementations include high-speed image
applications (such as Group IV facsimile), high-speed file transfer, videoconferencing,
and multiple links into homes of telecommuters.
ISDN is actually a set of communication protocols proposed by telephone
companies that allows them to carry a group of digital services that
simultaneously convey data, text, voice, music, graphics, and video to end
users, and it was designed to achieve this over the telephone systems
already in place. ISDN is referenced by a suite of ITU-T standards that
encompass the OSI model’s Physical, Data Link, and Network layers. The
ISDN standards define the hardware and call-setup schemes for end-to-end
digital connectivity.
PPP is typically used with ISDN to provide data encapsulation, link integrity,
and authentication. These are the benefits of ISDN:
� Can carry voice, video, and data simultaneously
� Has faster call setup than a modem
� Has faster data rates than a modem connection