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Computer Networks/Networks




                    Notes          Bounded Media Comparison Chart
                                                       Table 3.2: Bounded Media Comparison Chart


                                        Media             Advantages                   Disadvantages
                                      Twisted Pair   Inexpensive, well established, easy   Sensitive to noise, short distances, limited
                                      Cable       to add nodes                bandwidth, security hazard because of
                                                                              easy interception
                                      Coaxial     High bandwidth, long distances,   Physical dimensions,  security is better in
                                      Cable       noise immunity              comparison to twisted pair cable
                                      Optical Fiber   Very high bandwidth, noise    Connections, cost
                                      Cable       immunity, long distances, high
                                                  security, small size





                                      Task  Give a brief description of the application and limitations of the following types of
                                     transmission media:
                                     (a)  Two-wire open lines
                                     (b)  Twisted pair lines
                                     (c)  Coaxial cable

                                     (d)  Optical fiber
                                     (e)  Microwaves

                                   3.3 Summary

                                       There are several kinds of transmission media. These media technologies starting from
                                       copper wire to wireless and fiber optic has grown-up so rapidly and replacing other very
                                       quickly in this information age.

                                       Transmission media can be brodadly classified into two types: Guided and Unguided
                                       transmission media.
                                       Twisted pair, coaxial cable and optical fiber fall into the category of guided or bounded
                                       transmission media.
                                       Twisted pair is a pair of copper wires twisted together and wrapped with a plastic coating.
                                       It is mainly of two types: shielded twisted pair(STP) and Unshielded twisted pair (UTP).

                                       Shielded twisted pair (STP) differs from UTP in that a metallic shield or screen surrounds
                                       the pairs, which may or may not be twisted.

                                       Coaxial Cable is a very robust shielded copper wire two-conductor cable in which a solid
                                       center conductor runs concentrically (coaxial) inside a solid outer circular conductor.
                                       Optical fiber carries the transmitted information in the form of a fluctuating beam of light
                                       in a glass fiber rather than as an electrical signal on a wire. It can be of two types: monomode
                                       and multimode fiber.










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