A Word about ISDN
You've reached this page because RAD University has deprecated its tutorial on ISDN. ISDN (Integrated Services Digital Network) is a technology from the 1980s that has never had tremendous success (some people said that the acronym ISDN stands for "I still don't (k)now.") It mostly served homes and small businesses by providing voice and data communications with one physical link. ISDN was a "last mile" technology that has been replaced most commonly by ADSL.
In the event that you are still interested in ISDN, you can find a brief summary of the key features by choosing the appropriate link to the left. Otherwise, choose one of the other links that we think might be of interest instead.
Home and Small Business Environments - ADSL
In the home and small business environments, ISDN has been replaced by ADSL and even higher speed last mile solutions, such as Passive Optical Fiber Networks. Choose the tutorials on ADSL and IP over ADSL in the left-hand menu.
Enterprise Environment - ATM
In the enterprise environment, ATM - the implementation of Broadband ISDN, was the next generation technology after ISDN to provide integration of voice, data, and video. Since on this page the focus is on replacements for ISDN, ATM was the natural next-generation "last mile" solution for the enterprise. However, given convergence of "everything" over IP, it is far from the only solution, nor is it only a "last mile" technology. And, though ATM was the next generation technology after ISDN to provide integration of voice, data, and video, IP/MPLS is now considered the choice for "everything" over IP. You can find other infrastructure technologies in the "Infrastructure" menu on the RAD University home page. For tutorials on ATM, you can choose the link to the ATM portal in the left-hand menu, or you can choose the link to the MPLS portal.
Thank you for visiting RAD University. We hope that the suggested tutorials will be helpful.
Debby Koren, "Dean" RAD University
