A network required a physical medium to connect its nodes. The physical media is where the data actually flows. You have most likely heard about OSI reference model, which defines network hardware and services in terms of the functions they perform. The OSI reference model we already discussed in detail in Chapter 1, (“Network and their building blocks.”) Transmission media work at Layer 1(physical layer) of the OSI model:The physical layer represents bits as voltages, radio frequencies; or light pulses so various standards organizations have contributed to the definition of the physical; electrical, and mechanical properties of the media available for different data communications. These characteristics guarantee; that cables and connectors will function as expected with different data link layer implementations. There are three main categories of media types that will be discussed in detail later:
Types of cable include unshielded twisted-pair (UTP), shielded twisted-pair (STP), and coaxial cable. Copper-based cables are inexpensive and easy to work with compared to fiber-optic cables, but as you’ll learn when we get into the particulars, the main disadvantage of copper cable is that it offers a limited range that cannot handle the advanced applications.
Fiber offers huge data bandwidth, protection to many types of noise and interference, and enhanced security.
So, fiber provides clear communications and a comparatively noise-free environment. The disadvantage of fiber is that it is costly to purchase and it requires specialized equipment and techniques for installation.
Wireless media include radio frequencies, microwave, satellite, and infrared. Deployment of wireless media is faster and less costly than the deployment of cable, mostly where there is no existing infrastructure. There are a few disadvantages associated with wireless. It supports much lower data rates than do wired media. Wireless is also greatly affected by external environments, such as the impact of weather, as a result reliability can be difficult to guarantee.