3 Physical Media Copper Coaxial Cable - Thick or Thin Unshielded Twisted Pair - CAT 3,4,5,5e&6Optical FiberMultimodeSinglemodeWirelessShort RangeMedium Range (Line of Sight)Satellite
4 Copper Media: Coaxial Cable Physical MediaCopper Media: Coaxial CableCoaxial cable is a copper- cored cable surrounded by a heavy shielding and is used to connect computers in a network.Outer conductor shields the inner conductor from picking up stray signal from the air.High bandwidth but lossy channel.Repeater is used to regenerate the weakened signals.CategoryImpedanceUseRG-5975 Cable TVRG-5850 Thin EthernetRG-11Thick Ethernet
5 Copper Media: Twisted Pair Physical MediaCopper Media: Twisted PairTwisted-pair is a type of cabling that is used for telephone communications and most modern Ethernet networks.A pair of wires forms a circuit that can transmit data. The pairs are twisted to provide protection against crosstalk, the noise generated by adjacent pairs.There are two basic types, shielded twisted-pair (STP) and unshielded twisted-pair (UTP).
8 Unshielded Twisted Pair (UTP) Physical MediaUnshielded Twisted Pair (UTP)Consists of 4 pairs (8 wires) of insulated copper wires typically about 1 mm thick.The wires are twisted together in a helical form.Twisting reduces the interference between pairs of wires.High bandwidth and High attenuation channel.Flexible and cheap cable.Category rating based on number of twists per inch and the material usedCAT 3, CAT 4, CAT 5, Enhanced CAT 5 and now CAT 6.
9 Physical MediaCategories of UTPUTP comes in several categories that are based on the number of twists in the wires, the diameter of the wires and the material used in the wires.Category 3 is the wiring used primarily for telephone connections.Category 5e and Category 6 are currently the most common Ethernet cables used.
10 Categories of UTP: CAT 3 Bandwidth 16 Mhz 11.5 dB Attenuation Physical MediaCategories of UTP: CAT 3Bandwidth 16 Mhz11.5 dB Attenuation100 ohms ImpedanceUsed in voice applications and 10baseT (10Mbps) Ethernet
11 Categories of UTP: CAT 4 20 MHz Bandwidth 7.5 dB Attenuation Physical MediaCategories of UTP: CAT 420 MHz Bandwidth7.5 dB Attenuation100 ohms ImpedanceUsed in 10baseT (10Mbps) Ethernet
12 Categories of UTP: CAT 5 100 MHz Bandwidth 24.0 dB Attenuation Physical MediaCategories of UTP: CAT 5100 MHz Bandwidth24.0 dB Attenuation100 ohms ImpedanceUsed for high-speed data transmissionUsed in 10BaseT (10 Mbps) Ethernet & Fast Ethernet (100 Mbps)
13 Categories of UTP: CAT 5e Physical MediaCategories of UTP: CAT 5e150 MHz Bandwidth24.0 dB Attenuation100 ohms ImpedanceTransmits high-speed dataUsed in Fast Ethernet (100 Mbps), Gigabit Ethernet (1000 Mbps) & 155 Mbps ATM
14 Categories of UTP: CAT 6 250 MHz Bandwidth 19.8 dB Attenuation Physical MediaCategories of UTP: CAT 6250 MHz Bandwidth19.8 dB Attenuation100 ohms ImpedanceTransmits high-speed dataUsed in Gigabit Ethernet (1000 Mbps) & 10 Gig Ethernet (10000 Mbps)
15 Physical MediaFiber MediaOptical fibers use light to send information through the optical medium.It uses the principal of total internal reflection.Modulated light transmissions are used to transmit the signal.
16 Total Internal Reflection Physical MediaTotal Internal Reflection
17 Physical MediaFiber MediaLight travels through the optical media by the way of total internal reflection.Modulation scheme used is intensity modulation.Two types of Fiber media :MultimodeSinglemodeMultimode Fiber can support less bandwidth than Singlemode Fiber.Singlemode Fiber has a very small core and carry only one beam of light. It can support Gbps data rates over > 100 Km without using repeaters.
18 Single and Multimode Fiber Physical MediaSingle and Multimode FiberSingle-mode fiberCarries light pulses along single pathUses Laser Light SourceMultimode fiberMany pulses of light generated by LED travel at different angles
19 Physical MediaFiber MediaThe bandwidth of the fiber is limited due to the dispersion effect.Distance Bandwidth product of a fiber is almost a constant.Fiber optic cables consist of multiple fibers packed inside protective covering.62.5/125 µm (850/1310 nm) multimode fiber50/125 µm (850/1310 nm) multimode fiber10 µm (1310 nm) single-mode fiber
20 Fiber-Optic Cable Contains one or several glass fibers at its core Physical MediaFiber-Optic CableContains one or several glass fibers at its coreSurrounding the fibers is a layer called cladding
21 Fiber Optic Cable FO Cable may have 1 to over 1000 fibers Physical MediaFiber Optic CableFO Cable may have 1 to over 1000 fibers
22 Physical MediaWireless MediaVery useful in difficult terrain where cable laying is not possible.Provides mobility to communication nodes.Right of way and cable laying costs can be reduced.Susceptible to rain, atmospheric variations and Objects in transmission path.
23 Wireless Media Indoor : 10 – 50m : BlueTooth, WLAN Physical MediaWireless MediaIndoor : 10 – 50m : BlueTooth, WLANShort range Outdoor : 50 – 200m: WLANMid Range Outdoor : 200m – 5 Km : GSM, CDMA, WLAN Point-to-Point, Wi-MaxLong Range Outdoor : 5 Km – 100 Km : Microwave Point-to-PointLong Distance Communication : Across Continents : Satellite Communication
24 Frequency Bands Physical Media Band Range Propagatio n Application VLF 3–30 KHzGroundLong-range radio navigationLF30–300 KHzRadio beacons and navigational locatorsMF300 KHz–3 MHzSkyAM radioHF3–30 MHzCitizens band (CB), ship/aircraft communicationVHF30–300 MHzSky and line-of-sightVHF TV, FM radioUHF300 MHz–3 GHzLine-of- sightUHF TV, cellular phones, paging, satelliteSHF3–30 GHzSatellite communicationEHF30–300 GHz
25 Wireless LAN Router Physical Media Internet Access Point Access Point PCAccess PointInternetRouterSwitchPCAccess Point
26 Terrestrial Microwave Physical MediaTerrestrial MicrowaveMicrowaves do not follow the curvature of earthLine-of-Sight transmissionHeight allows the signal to travel fartherTwo frequencies for two way communicationRepeater is used to increase the distance Hop-by-Hop
27 Satellite Communication Physical MediaSatellite Communication
28 ADVANTAGESBandwidth - Fibre optic cables have a much greater bandwidth than metal cables. The amount of information that can be transmitted per unit time of fibre over other transmission media is its most significant advantage. With the high performance single mode cable used by telephone industries for long distance telecommunication, the bandwidth surpasses the needs of today's applications and gives room for growth tomorrow. Low Power Loss - An optical fibre offers low power loss. This allows for longer transmission distances. In comparison to copper; in a network, the longest recommended copper distance is 100m while with fibre, it is 2000m. Interference - Fibre optic cables are immune to electromagnetic interference. It can also be run in electrically noisy environments without concern as electrical noise will not affect fibre. Size - In comparison to copper, a fibre optic cable has nearly 4.5 times as much capacity as the wire cable has and a cross sectional area that is 30 times less. Weight - Fibre optic cables are much thinner and lighter than metal wires. They also occupy less space with cables of the same information capacity. Lighter weight makes fibre easier to install. Safety - Since the fibre is a dielectric, it does not present a spark hazard. Security - Optical fibres are difficult to tap. As they do not radiate electromagnetic energy, emissions cannot be intercepted. As physically tapping the fibre takes great skill to do undetected, fibre is the most secure medium available for carrying sensitive data. Flexibility - An optical fibre has greater tensile strength than copper or steel fibres of the same diameter. It is flexible, bends easily and resists most corrosive elements that attack copper cable.
29 DisadvantageCost - Cables are expensive to install but last longer than copper cables. Transmission - transmission on optical fibre requires repeating at distance intervals. Fragile - Fibres can be broken or have transmission loses when wrapped around curves of only a few centimetres radius. However by encasing fibres in a plastic sheath, it is difficult to bend the cable into a small enough radius to break the fibre. Protection - Optical fibres require more protection around the cable compared to copper.