). Consider an application that involves the transmission of images between an imaging center and a doctor's office. Say you went to the imaging center to have an x-ray of your lungs, and in the transmission of your lung x-ray, a little bit of noise in the network put a big black spot on your lung. If that happened, you would likely be scheduled for radi- cal surgery. So, for this type of application, you want a network that ensures that very little noise can affect the resolution and hence the outcome of the analysis. A lot of this use of fiber occurs in early-adopter scenarios where there are applica- tions for imaging, such as universities, health care environments, and entertain- ment applications. Another frontier where fiber is now of great interest is in home area networks (HANs). This is a very interesting area because when broadband access comes your home, you see a shift in where the bottleneck resides, from the local loop to inside the home. Broadband access into the home requires a broadband network within the home to properly distribute the entertainment, data, and voice services that are collectively transported over that broadband access. Many new homes are now being wired with fiber from the start, but it is also possible to retrofit an older home to provide high-quality entertainment and data networks. (HANs are dis- cussed in more detail in Chapter 12.) Advantages and Disadvantages of Fiber Optics The advantages of fiber optics are as follows: Extremely high bandwidth-Fiber offers far more bandwidth than any other cable-based medium. Elastic traffic-carrying capacity-Without having to change the fiber, assuming that it's the correct generation of fiber, you can add equipment that provides additional capacity over the original fiber alone. This, along with DWDM's capability to turn various wavelengths on and off at will, enables dynamic network bandwidth provisioning to accommodate fluctua- tions in traffic. Chapter 2 Traditional Transmission Media Not susceptible to electromagnetic impairments o