1. Objectives of Today’s Lecture Lecture Objectives In this Lecture, First we will learn about Physical Media, types of physical media is available and their specifications, :. By the end of this lecture, you should be able to know: What is Physical Media? What are the different types of Physical Media? What are Copper and Optical Fiber and what different types are available and their specifications? What are the different types if Wireless and which frequencies bands are available? What is satellites communication and how many types of satellites are available?

2. Physical Media PHYSICAL MEDIA

3. Physical Media 1010101010101010101010101

4. Transmission Media Guided Transmission Media (Physical Media) Magnetic Media Copper Media - Twisted Pairs STP – Shielded Twisted Pair - Thick or Thin UTP – Unshielded Twisted Pair CAT 3,4,5,5e&6 Coaxial Cable Fiber Optics Single Mode Multi Mode Unguided Transmission Media (Wireless Transmission) The Electromagnetic Spectrum Radio Transmission (Radio Frequency RF) Microwave Transmission Satellites Communication. Physical Media

5. Copper Media: Coaxial Cable Coaxial 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. Physical Media CategoryImpedanceUseRG-59 75  Cable TV RG-58 50  Thin Ethernet RG-11 50  Thick Ethernet

6. Copper Media: Twisted Pair Twisted-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). Physical Media

7. Shielded Twisted Pair (STP) Physical Media

8. Unshielded Twisted Pair (UTP) Physical Media

9. Unshielded 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 used CAT 3, CAT 4, CAT 5, Enhanced CAT 5 and now CAT 6. Physical Media

10. Categories of UTP UTP 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 rating based on number of twists per inch and the material used CAT 3, CAT 4, CAT 5, Enhanced CAT 5e CAT 6. Category 3 is the wiring used primarily for telephone connections. Category 5e and Category 6 are currently the most common Ethernet cables used. Physical Media

11. Categories of UTP: CAT 3 Bandwidth 16 Mhz 11.5 dB Attenuation 100 ohms Impedance Used in voice applications and 10baseT (10Mbps) Ethernet Physical Media

12. Categories of UTP: CAT 4 20 MHz Bandwidth 7.5 dB Attenuation 100 ohms Impedance Used in 10baseT (10Mbps) Ethernet Physical Media

13. Categories of UTP: CAT 5 100 MHz Bandwidth 24.0 dB Attenuation 100 ohms Impedance Used for high-speed data transmission Used in 10BaseT (10 Mbps) Ethernet & Fast Ethernet (100 Mbps) Physical Media

14. Categories of UTP: CAT 5e 150 MHz Bandwidth 24.0 dB Attenuation 100 ohms Impedance Transmits high-speed data Used in Fast Ethernet (100 Mbps), Gigabit Ethernet (1000 Mbps) & 155 Mbps ATM Physical Media

15. Categories of UTP: CAT 6 250 MHz Bandwidth 19.8 dB Attenuation 100 ohms Impedance Transmits high-speed data Used in Gigabit Ethernet (1000 Mbps) & 10 Gig Ethernet (10000 Mbps) Physical Media

16. Fiber Media Optical 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. Physical Media

17. Total Internal Reflection Physical Media

18. Fiber Media Light travels through the optical media by the way of total internal reflection. Modulation scheme used is intensity modulation. Two types of Fiber media : Multimode Singlemode Multimode 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. Physical Media

19. Single and Multimode Fiber Single-mode fiber Carries light pulses along single path Uses Laser Light Source Multimode fiber Many pulses of light generated by LED travel at different angles Physical Media

20. Fiber Media The 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 fiber 50/125 µm (850/1310 nm) multimode fiber 10 µm (1310 nm) single-mode fiber Physical Media

21. Fiber-Optic Cable Contains one or several glass fibers at its core Surrounding the fibers is a layer called cladding Physical Media

22. Fiber Optic Cable FO Cable may have 1 to over 1000 fibers Physical Media

23. Wireless Media Very 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. Physical Media

24. Wireless Media Indoor : 10 – 50m : BlueTooth, WLAN Short range Outdoor : 50 – 200m: WLAN Mid Range Outdoor : 200m – 5 Km : GSM, CDMA, WLAN Point-to-Point, Wi-Max Long Range Outdoor : 5 Km – 100 Km : Microwave Point-to-Point Long Distance Communication : Across Continents : Satellite Communication Physical Media

25. Frequency Bands Physical MediaBandRange Propagatio n ApplicationVLF3–30 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 GHz Line-of- sight UHF TV, cellular phones, paging, satellite SHF3–30 GHz Line-of- sight Satellite communication EHF30–300 GHz Line-of- sight Long-range radio navigation

26. Wireless LAN Physical Media Internet Router Switch Access Point PC

27. Terrestrial Microwave Microwaves do not follow the curvature of earth Line-of-Sight transmission Height allows the signal to travel farther Two frequencies for two way communication Repeater is used to increase the distance Hop-by-Hop Physical Media

28. Satellite Communication Physical Media

29. Satellite Communication Physical Media The first artificial communication satellite, Telstar, was launched in July 1962. Geostationary (or geosynchronous) earth orbit (GEO). Medium earth orbit (MEO). Low earth orbit (LEO). Highly elliptical orbit (HEO).

30. Satellite Communication Physical Media Different types of satellite orbits

31. GEO Satellites Physical Media Geostationary (or geosynchronous) earth orbit (GEO): GEO satellites have a distance of almost 36,000 km (22, 300 miles) to the earth. (in book 35,800 km) Fixed position in space in relations to the earth surface. Examples are almost all TV and radio broadcast satellites, many weather satellites and satellites operating as backbones for the telephone network. GEOs are ideal for TV and radio broadcasting.

32. MEOs Satellites Physical Media Medium earth orbit (MEO): MEOs operate at a distance of about 5,000–12,000 km (1,000 to 22,300 miles). (in book 20,200 km) Not Stationary in relation to the rotation of the earth. MEOs mostly used in GPS (Global Positioning System). Up to now there have not been many satellites in this class, but some upcoming systems (e.g., ICO) use this class for various reasons.

33. LEO Satellites Physical Media Low earth orbit (LEO): LEO orbit earth between altitudes of 500–1,500 km (400 to 1000 miles) above the earth surface. LEO Mostly used for data communication such as paging, email and video conferencing etc. Not fix in space in relation to the rotation of the earth, they move at very high speed.

34. HEO Satellites Physical Media Highly elliptical orbit (HEO): This class comprises all satellites with noncircular orbits. Currently, only a few commercial communication systems using satellites with elliptical orbits are planned. These systems have their perigee over large cities to improve communication quality.

35. Multiple Access Physical Media One of the concept in data communication is the idea of allowing several transmitters to send information simultaneously over a single communication channel. This allows several users to share a band of frequencies. This concept is called multiple access. FDMA: Frequency Division Multiple Access Divides the access by frequency. TDMA: Time Division Multiple Access Divides the access by time. CDMA: Code Division Multiple Access. Employs spread-spectrum technology and a special coding scheme to allow multiple users to be multiplexed over the same physical channel.

36. The Public Switched Telephone Network Physical Media Also called PSTN Colloquially referred as Plain old telephone services. A term that describes the assortment of telephone networks and services available globally. Transmitting the human voice in a more-or-less recognizable form. Structure of the Telephone System Alexander Graham Bell patented the telephone in 1876.

37. The Mobile Telephone System Physical Media The traditional telephone system (even if it some day gets multi gigabit end-to-end fiber) will still not be able to satisfy a growing group of users: people on the go. People now expect to make phone calls from airplanes, cars, swimming pools, and while jogging in the park. Wireless telephones come in two basic varieties: Cordless phones and Mobile phones. Mobile phones have gone through three distinct generations, with different technologies: Analog voice. (1G) Digital voice. (2G) Digital voice and data (Internet, e-mail, etc.). (3G)

38. Overview of Cellular System Physical Media

39. Overview of Cellular System Physical Media

40. First-Generation (1G): Analog Voice Physical Media In 1960, IMTS – Improved Mobile Telephone System was installed. IMTS supported 23 channels spread out from 150 MHz to 450 MHz. Advanced Mobile Phone System (AMPS) Invented by Bell Labs and first installed in the United States in 1982. In all mobile phone systems, a geographic region is divided up into cells, which is why the devices are sometimes called cell phones. In AMPS, the cells are typically 10 to 20 km across. Each cell uses some set of frequencies not used by any of its neighbors. An AMPS system might have 100 10-km cells in the same area and be able to have 10 to 15 calls on each frequency, in widely separated cells.

41. Second-Generation (2G) Mobile Phones: Digital Voice Physical Media The first generation of mobile phones was analog; The second generation is digital. Switching to digital has several advantages. It provides capacity gains by allowing voice signals to be digitized and compressed. It improves security by allowing voice and control signals to be encrypted. This in turn deters fraud and eavesdropping, whether from intentional scanning or echoes of other calls due to RF propagation. Finally, it enables new services such as text messaging. GSM—The Global System for Mobile Communications. GSM started life in the 1980s as an effort to produce a single European 2G standard. The first GSM systems were deployed starting in 1991 and were a quick success.

42. Second-Generation (2G) Mobile Phones: Digital Voice Physical Media

43. Third-Generation (3G) Mobile Phones: Digital Voice and Data Physical Media The first generation of mobile phones was analog voice. The second generation was digital voice. The third generation of mobile phones, or 3G as it is called, is all about digital voice and data. Apple’s iPhone is a good example of this kind of 3G device. ITU tried to get a bit more specific about this vision starting back around 1992. It issued a blueprint for getting there called IMT-2000. IMT - International Mobile Telecommunications. IMT-2000 network was supposed to provide to its users are: High-quality voice transmission. Messaging (replacing email, fax, SMS, chat, etc.). Multimedia (playing music, viewing videos, films, television, etc.). Internet access (Web surfing, including pages with audio and video).

44. Handoffs/Handover Physical Media In cellular telecommunication, the term handover or handoff refers to the process of transferring an ongoing call or data session from one channel connected to the core network to another. TWO Types of Handoff Hard Handoff The mobile station(MS) connects with only one base station at a time and there is usually some interruption during the conversation. Soft Handoff The mobile station (MS) receives or transmit the same signals from Multiple Base Station (BS) simultaneously.

45. Mobile Channels Physical Media There are mainly two Channels Control Channel Traffic Channel Control Channel: Setting up and maintaining calls Establish relationship between mobile unit and nearest base station. Traffic Channel: Carry voice and data.

46. Cable Television Physical Media We have now studied both the fixed and wireless telephone systems in a fair amount of detail. Both will clearly play a major role in future networks. However, an alternative available for fixed networking is now becoming a major player: cable television networks. Many people already get their telephone and Internet service over the cable, cable television as a networking system in more detail and contrast