CCIE Practical Studies, Volume I

Chapter 7. WAN Protocols and Technologies: Integrated Services Digital Network (ISDN)

Authoring contribution by Daniel Keller

Integrated Services Digital Network (ISDN) is basically the digital version of the Public Switched Telephone Network (PSTN). It offers a common platform for integrating voice, video, and data services globally. When discussing ISDN, we actually are talking about Narrowband ISDN (N-ISDN). The other type of ISDN is referred to as Broadband ISDN (B-ISsDN), which provides high-speed transmissions and is the foundation behind ATM, which is addressed in more depth in Chapter 8, "WAN Protocols and Technologies: Asynchronous Transfer Mode (ATM)."