Ethernet Networking- P3

Ethernet Networking- P3:One of the biggest problems when discussing networking is knowing whereto start. The subject of computer networks is one of those areas for whichyou have to "know everything to do anything." Usually, the easiest way toease into the topic is to begin with some basic networking terminology andthen look at exactly what it means when we use the word Ethernet.
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Ethernet Networking- P348 Fast and Gigabit Ethernet Media and Standards attenuation. Fiber optic media can therefore be used in situa- tions where wire media pose problems, such as on factory floors. # It is much harder for someone to tap than wire media. # It is much less susceptible to attenuation than wire media. # It has much higher bandwidth than most wire media. The same fi- ber optic media can carry Ethernet signals at any standard speed. On the other hand, fiber optic cabling is more difficult to work with than wire. It cannot be spliced and taped with electrical tape like wire, but in- stead requires special connectors that precisely line up the ends of two seg- ments of cable with one another. In addition, fiber optic equipment is more expensive than equipment for wire media. Nonetheless, in environments where many devices share network media (in particular, linking servers) or where severe electrical interference is a factor, fiber optic cabling is a viable choice. For example, in graphics and video design firms where large files move between workstations, fiber op- tic cabling can significantly speed up workflow by providing additional bandwidth.5ing/e versus Multimode Fiber Optics There are two types of fiber optic cabling, single mode and multimode. Sin- gle mode, which can transmit a single wavelength of light long distances, is used primarily for WAN connections. Multimode can transmit multiple sig- nals at one tim, but is more limited in length and typically used in LANs. When light is introduced into an optical fiber, it can either go straight down the middle of the optical tube or it can travel at an angle, reflecting off the side of the tube as it travels. Each signal traveling down the tube at a time is known as a mode. The diameter of the core of a single-mode fiber is very small (for example, 9 microns). A single ray of light is transmitted down the core, and it travels without reflection straight to its destination. In theory, one single-mode fi- ber link can be as long as 10 kilometers.Fiber Optic Cabling 49 Multimode fiber has a larger core diameter and supports the transmission of multiple signals. Each ray of light has a different angle of reflection, making it possible for the receiving device to separate the individual sig- nals. (See Figure 3-6.) However, the reflection angles disperse over dis- tances (modal dispersion), spreading the signals and ultimately making it impossible to tell the signals apart. This limits the distance of multimode fiber. If the core is 62.5 microns in diameter, the maximum length is ap- proximately 275 meters; 50 micron fiber can go as far as 550 meters. r- Cladding Modes ~, travel Multiple i ~, different distances concurrently~ modes I ~ transmitted [ and therefore exist at different times Cladding Figure 3-6: Multiple signals traveling down multimode fiber Multimode fiber is generally easier to work with than single mode. Be- cause fiber optic cabling cannot be spliced, the ends of two pieces of single mode fiber must the aligned precisely when they are to be used as a single run of cable. Multimode fiber, because of its shorter runs, often doesnt need to be assembled out of multiple pieces of cabling; it can use a single unbroken piece of fiber.Fiber Optic Cable Bundles Just as UTP cable ...