[…] For mobile computers and telephones, cellular radio is the up-and-coming technology. GSM, CDPD, and CDMA are widely used. The IEEE 802 LANs are: CSMA/CD, token bus, and token ring. Each of these has its own unique advantages and disadvantages, and each has found its own user community and will probably continue to serve that community for years to come. Convergence to a single LAN standard is an unlikely event. A new addition to this family is DQDB, being sold as a MAN in many cities. An organization with multiple LANs often connects them with bridges. When a bridge connects two or more different kinds of LANs, new problems arise, some of them insoluble. […]