McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Chapter 7 Transmission Media

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.1 Transmission medium and physical layer

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.2 Classes of transmission media

McGraw-Hill©The McGraw-Hill Companies, Inc., Guided Media Twisted-Pair Cable Coaxial Cable Fiber-Optic Cable

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.3 Twisted-pair cable

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Cable Twisted pair cable implies the use of balanced signaling Twisted pair is used in telephony as well as local area networking The shield can be wrapped around a single pair or over an entire group of pairs Twisted Pair Cable

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.4 UTP and STP

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Table 7.1 Categories of unshielded twisted-pair cables CategoryBandwidthData RateDigital/AnalogUse 1very low< 100 kbpsAnalogTelephone 2 < 2 MHz2 MbpsAnalog/digitalT-1 lines 3 16 MHz 10 MbpsDigitalLANs 4 20 MHz 20 MbpsDigitalLANs MHz 100 MbpsDigitalLANs 6 (draft) 200 MHz 200 MbpsDigitalLANs 7 (draft) 600 MHz 600 MbpsDigitalLANs

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.5 UTP connector

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 UTP Cable and Connectors PALO ALTO, Calif., and PISCATAWAY, NJ,- June 28, Members of the IEEE and the Gigabit Ethernet Alliance today announced that the final milestone in the IEEE standards approval process was reached last week when the 1000BASE-T specification for Gigabit Ethernet over copper (also known as IEEE Std 802.3ab) was unanimously approved as an IEEE standard by the IEEE Standards Association (IEEE-SA) Standards Board. The standard defines Gigabit Ethernet operation over distances of up to 100 meters using four pairs of CAT-5 balanced copper cabling… …1000BASE-T is important for three reasons," commented Colin Mick, technical editor of the IEEE 802.3ab Task Force. "First, most of the cabling installed inside buildings today is CAT-5 UTP, and 1000BASE-T will enable Gigabit Ethernet operation over this installed base. Second, 1000BASE-T, on a per-connection basis, is expected to be very cost-effective which will stimulate market demand. Finally, 1000BASE-T allows auto-negotiation between 100 and 1000 Mb/s which eases the migration path for customers."

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.6 UTP performance

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.7 Coaxial cable

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Table 7.2 Categories of coaxial cables CategoryImpedanceUse RG  Cable TV RG  Thin Ethernet RG  Thick Ethernet

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.8 BNC connectors

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.9 Coaxial cable performance

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Bending of light ray Think of a mirage. You look along a road surface on a hot day and see the reflected sky, looking for all the world like a pool of water. Think of window glass on the front of a department store. As you walk down the sidewalk you can’t see what’s inside. Once you’re in front of the window it’s easy to see inside. These effects are related to the “Critical Angle”

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.10 Bending of light ray

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.11 Optical fiber

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.12 Propagation modes

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.13 Modes

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Table 7.3 Fiber types TypeCoreCladdingMode 50/ Multimode, graded-index 62.5/ Multimode, graded-index 100/ Multimode, graded-index 7/ Single-mode

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.14 Fiber construction

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.15 Fiber-optic cable connectors

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.16 Optical fiber performance

McGraw-Hill©The McGraw-Hill Companies, Inc., Unguided Media: Wireless Radio Waves Microwaves Infrared

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.17 Electromagnetic spectrum for wireless communication

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.18 Propagation methods

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Table 7.4 Bands BandRangePropagationApplication VLF3–30 KHzGroundLong-range radio navigation LF30–300 KHzGround Radio beacons and navigational locators MF300 KHz–3 MHzSkyAM radio HF3–30 MHzSky Citizens band (CB), ship/aircraft communication VHF30–300 MHz Sky and line-of-sight VHF TV, FM radio UHF300 MHz–3 GHzLine-of-sight UHF TV, cellular phones, paging, satellite SHF3–30 GHzLine-of-sightSatellite communication EHF30–300 GHzLine-of-sightLong-range radio navigation

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.19 Wireless transmission waves

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Radio waves are used for multicast communications, such as radio and television, and paging systems. They use a frequency spectrum from 3KHz to 300 MHz

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.20 Omnidirectional antennas

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Omnidirectional antenna

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Microwaves are used for unicast communication such as cellular telephones, satellite networks, and wireless LANs. They use the frequency spectrum from 300 MHz to 300 GHz

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 7.21 Unidirectional antennas

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Dish antennas

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Horn antenna Note the Cell antenna below the horns

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Cell Telephone antennas

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Infrared signals can be used for short- range communication in a closed area using line-of-sight propagation. Not used commercially for LANs Used commercially for short links Infrared starts at 300 GHz Infrared