. The main factor that inhibits or potentially slows the growth of microwave is that only SO many people can be operating on the same frequencies in the same area. Therefore, a big limitation of microwave is potential congestion in key metro- politan areas. Microwave has a disaster-recovery application as well. Because microwave is relatively inexpensive and quick to deploy, it is a good candidate for use after a disaster damages wireline media, systems, or structures. Transmitter Transmitter Receiver Receiver Interface Interface Uptown Downtown Facilities Facilities Figure 2.5 A LAN interconnect using microwave Chapter 2 Traditional Transmission Media Advantages and Disadvantages of Microwave The advantages of microwave are as follows: Cost savings-Using microwave is less expensive than using leased lines. Portability and reconfiguration flexibility-You can pick up a microwave transceiver and carry it to a new building. You can't do that with cables. Substantial bandwidth-A substantial amount of microwave bandwidth is allocated, so high-speed data, video, and multimedia can be supported. The main disadvantages of microwave are as follows: Line-of-sight requirement-You need to ensure that there are no obstacles between towers. Susceptibility to environmentally caused distortions-Because the envi- ronment (e.g., heavy rainstorms) can cause distortion, you need to have backups. Regulatory licensing requirement-The requirement for regulatory licens- ing means that you must have time and flexibility to deal with the spectrum agency. Potential environmental restrictions-Some communities do not allow microwave towers or require that they be camouflaged. The New Era of Microwave: Wireless Broadband As mentioned earlier, the initial application of microwave was focused on the replacement of twisted-pair and coaxial cables used in the PSTN. In fact, MCI first utilized microwave to provide voice and data service, introducing the first major competitive action against AT&T, which until 1984 had a monopoly on local and long-