Overview
Many types of WAN technologies can be implemented to solve connectivity issues for users who need network access from remote locations. In this chapter, you will learn about the services, standards, components, operation, and configuration of Integrated Services Digital Network (ISDN) communication. ISDN is specifically designed to solve the low bandwidth problems that small offices or dial-in users have with traditional telephone dial-in services. 

Telephone companies developed ISDN with the intention of creating a totally digital network. ISDN was developed to use the existing telephone wiring system, and it works very much like a telephone. When you make a data call with ISDN, the WAN link is brought up for the duration of the call and is taken down when the call is completed; it's very similar to how you call a friend on the phone and then hang up when you are done talking.

Threaded Case Study
  Washington Project: ISDN Connectivity

In this chapter, you will learn the concepts and configuration process needed to implement an ISDN connection in the Washington School District WAN. You need to provide an ISDN connection for a remote site that needs part-time connectivity to the district.