CT1403 Lecture#1:Transmission Media http://ecomputernotes.com/computernetworkingnotes/communication-networks/what-is-transmission-media-and-types-of-transmission-media CT1403 Lecture#1:Transmission Media Asma Alosaimi , 2016

Topics: Review Transmission media types Copper Media Fiber Optical Media Wireless Media

Data The two models Data Link Header IP Header TCP Header HTTP Header Data Link Trailer Data

TCP/IP Protocol Suite and Communication

Protocol Data Units (PDUs)

Transmission Media

The Physical Layer Section 4.1.2.1 Encoding or line encoding - Method of converting a stream of data bits into a predefined "codes”. Signaling - The physical layer must generate the electrical, optical, or wireless signals that represent the "1" and "0" on the media.

Physical Layer Media The physical layer produces the representation and groupings of bits for each type of media as: Copper cable: The signals are patterns of electrical pulses. Fiber-optic cable: The signals are patterns of light. Wireless: The signals are patterns of microwave transmissions. Section 4.1.2.2

Fundamental Principles of Layer 1 :Bandwidth Bandwidth is the capacity of a medium to carry data. Typically measured in kilobits per second (kb/s) or megabits per second (Mb/s). Section 4.1.3.2

Fundamental Principles of Layer 1 Throughput Throughput is the measure of the transfer of bits across the media over a given period of time. Due to a number of factors, throughput usually does not match the specified bandwidth in physical layer implementations. http://www.speedtest.net/ http://ipv6-test.com/speedtest/ Section 4.1.3.3

Transmission Media LANs consist of Transmission media and network nodes. Transmission media is a pathway that carries the information from sender to receiver . We use different types of cables or waves to transmit data.

Connectors Connectors Hardware pieces connecting wire to network device Every networking medium requires a specific kind of connector The type of connector you use affect the cost of Installing and maintaining network Ease of adding new segments or nodes Technical expertise required to maintain network

Media Converters Connectors are specific to a particular media type, but that doesn’t prevent one network from using multiple media. Some connectivity devices are designed to accept more than one type of media. If not, we can integrate the two media types by using media converters. Media converter A piece of hardware enabling networks or segments running on different media to interconnect and exchange signals For example, suppose a segment leading from your company’s data center to a group of workstations uses fiber-optic cable, but the workgroup hub can only accept twisted pair (copper) cable. In that case, you could use a media converter to interconnect the hub with the fiber-optic cable. The media converter completes the physical connection and also converts the electrical signals from the copper cable to light wave signals that can traverse the fiber-optic cable, and vice versa.

Figure 3-15 Copper wire-to-fiber media converter

Copper Media Section 4.2.1.2

Characteristics of Copper Media 2 1 4 3 Section 4.2.1.1 Signal attenuation - the longer the signal travels, the more it deteriorates - susceptible to interference Crosstalk - a disturbance caused by the electric or magnetic fields of a signal on one wire to the signal in an adjacent wire.

Twisted Pair Cable Twisted pair cable consists of color-coded insulated copper wire pairs Every two wires are twisted around each other to form pairs all the pairs are encased in a plastic sheath The number of pairs in a cable varies, depending on the cable type Figure 3-19 Twisted pair cable

Twisted Pair Cable (cont’d.) The more wire pair twists per foot The more resistance the pair to cross talk Higher-quality More expensive twisted pair cable Twist ratio The number of twists per meter or foot High twist ratio Greater attenuation

Twisted Pair Cable (cont’d.) Because twisted pair is used in such a wide variety of environments and for a variety of purposes, it comes in hundreds of different designs These designs vary in their twist ratio, number of wire pairs, copper grade, shielding type, shielding materials A twisted pair cable may contain from1 to 4200 wire pairs possible Modern networks typically use cables that contain four wire pairs, in which one pair is dedicated to sending data and another pair is dedicated to receiving data Wiring standard specification TIA/EIA 568 Most common twisted pair types Category (cat) 3, 5, 5e, 6, 6a, 7 CAT 5 or higher used in modern LANs

Twisted Pair Cable (cont’d.) Advantages Relatively inexpensive Flexible Easy installation Spans significant distance before requiring repeater (though not as far as coax). Accommodates several different topologies, although it is most often implemented in star or star-hybrid topologies. Two categories Shielded twisted pair (STP) Unshielded twisted pair (UTP) Connector STP and UTP use Registered Jack 45 (RJ 45) Telephone connections use Registered Jack 11 (RJ 11)

Terminating Twisted Pair Cable (cont’d.) Termination tools Wire cutter Wire stripper Crimping tool After making cables: Verify data transmit and receive

Terminating Twisted Pair Cable Patch cable Relatively short cable ( usually between 3 and 25 feet) Connectors at both ends Proper cable termination techniques Basic requirement for two nodes to communicate Poor terminations: Lead to loss or noise TIA/EIA has specified two different methods of inserting twisted pair wires into RJ-45 plugs TIA/EIA 568A TIA/EIA 568B

STP (Shielded Twisted Pair) STP (shielded twisted pair) cable consists of twisted wire pairs that are not only Individually insulated but also surrounded by metallic substance shielding (foil) The shielding acts as a barrier to external electromagnetic forces It also contains electrical energy of signals inside May be grounded to enhance its protective effects Figure 3-20 STP cable

Unshielded Twisted-Pair (UTP) Cable Section 4.2.1.3

UTP categories Category 1 Voice only (Telephone) Category 2 Data to 4 Mbps (Localtalk) Category 3 Data to 10Mbps (Ethernet) Category 4 Data to 20Mbps (Token ring) Category 5 Category 5e Data to 100Mbps (Fast Ethernet) Data to 1000Mbps (Gigabit Ethernet) Category 6 Data to 2500Mbps (Gigabit Ethernet)

UTP EIA/TIA-568A/B compliant refers to which of the four pairs in the UTP cable are designated as transmit, and which are designated as receive. Use the following as a guide: EIA/TIA-568A: Devices transmit over pair 3, and receive over pair 2. EIA/TIA-568B: Devices transmit over pair 2, and receive over pair 3.

Termination — EIA/TIA-568A

Termination — EIA/TIA-568B

UTP Implementation: Straight-Through

UTP Implementation: CrossOver

Straight-Through Vs. Crossover Use straight-through cables for the following cabling: Switch to Router. Switch to Server (PC). Hub to Server (PC). Use crossover cables for the following cabling: Switch to Switch. Switch to Hub. Hub to Hub. Router to Router. PC to PC

Shielded Twisted-Pair (STP) Cable Braided or Foil Shield Foil Shields Section 4.2.1.4 UTP cable does not use shielding to counter the effects of EMI and RFI.  Instead, cable designers have discovered that they can limit the negative effect of crosstalk STP cable combines the techniques of shielding to counter EMI and RFI and wire twisting to counter crosstalk.

Coaxial Cable Section 4.2.1.5

Coaxial Cable When discussing the size of the conducting core: American Wire Gauge (AWG) size Larger AWG size, smaller wire diameter Data networks usage RG-6 : to deliver broadband cable Internet service and cable TV, particularly over long distances RG-8: 10Base-5 Ethernet (old) RG-58: is more flexible and easier to handle and install, 10Base-2 (old) RG-59: used for relatively short connections,

Coaxial Cable connectors The two coaxial cable types commonly used in networks today, RG-6 and RG-59, can terminate with one of two connector types: an F-type connector or a BNC connector Section 4.2.1.5 Figure 3-17 F-Type connector Figure 3-18 BNC connector

standards for Coaxial Cables EIA standards for Coaxial Cables

Fiber Optic Cabling Section 4.2.3.1

Fiber Media Cable Design Fiber-optic cable (fiber) One or more glass or plastic fibers at its center (core) Data transmission Pulsing light sent from laser or light-emitting diode (LED) through central fibers Cladding Layer of glass or plastic surrounding fibers Different density from glass or plastic in strands Reflects light back to core in patterns that vary depending on the transmission mode Allows fiber to bend Section 4.2.3.2

SMF (Single-Mode Fiber) Consists of narrow core (8-10 microns in diameter) Laser-generated light travels over one path Little reflection Light does not disperse as signal travels Can carry signals many miles: Before repeating required Rarely used for shorter connections Due to cost

MMF (Multimode Fiber) Contains core with larger diameter than single-mode fiber Common sizes: 50 or 62.5 microns Laser or LED generated light pulses travel at different angles Greater attenuation than single-mode fiber Common uses Cables connecting router to a switch Cables connecting server on network backbone

Network Fiber Connectors Section 4.2.3.4

Implementation issues Fiber versus Copper Implementation issues Copper media Fibre-optic Bandwidth supported 10 Mbps – 10 Gbps 10 Mbps – 100 Gbps Distance Relatively short (1 – 100 meters) Relatively High (1 – 100,000 meters) Immunity to EMI and RFI Low High (Completely immune) Immunity to electrical hazards Media and connector costs Lowest Highest Installation skills required Safety precautions Section 4.2.3.6

Wireless Media IEEE 802.11 standards Commonly referred to as Wi-Fi. Uses CSMA/CA Variations include: 802.11a: 54 Mbps, 5 GHz 802.11b: 11 Mbps, 2.4 GHz 802.11g: 54 Mbps, 2.4 GHz 802.11n: 600 Mbps, 2.4 and 5 GHz 802.11ac: 1 Gbps, 5 GHz 802.11ad: 7 Gbps, 2.4 GHz, 5 GHz, and 60 GHz IEEE 802.15 standard Supports speeds up to 3 Mbps Provides device pairing over distances from 1 to 100 meters. IEEE 802.16 standard Provides speeds up to 1 Gbps Uses a point-to-multipoint topology to provide wireless broadband access. Section 4.2.4.2

802.11 Wi-Fi Standards Standard Maximum Speed Frequency Backwards compatible 802.11a 54 Mbps 5 GHz No 802.11b 11 Mbps 2.4 GHz 802.11g 802.11n 600 Mbps 2.4 GHz or 5 GHz 802.11b/g 802.11ac 1.3 Gbps (1300 Mbps) 2.4 GHz and 5.5 GHz 802.11b/g/n 802.11ad 7 Gbps (7000 Mbps) 2.4 GHz, 5 GHz and 60 GHz 802.11b/g/n/ac Section 4.2.4.4

Recourses: L: Rehab AlFallaj, lecture notes Cisco slides