It is a switched network, which means that it has switches at each end. It is either switched on or switched off. In order for the ISDN to connect to the Internet, the user must dial to a special modem. ISDN is a group of 24 cables that can transmit data at 64 Kbps. These 24 cables are put together into one big cable that can transfer data at a maximum of 1.544 Mbps.
Frame relay puts the data in a size unit called a frame.
When an error is found, it is simply just thrown away. Frame relay is a dedicated line that is on 24 hours a day. It doesn't need the user to dial to a modem or phone company in order for it to connect to the Internet. Frame relay is a fast, inexpensive way to transmit data. Back Stan Loui talked to us about the three categories that GTE focuses on.