1. CT1403 Lecture#1:Transmission Media
CT1403 Lecture#1:Transmission Media
Asma Alosaimi , 2016

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

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

4. TCP/IP Protocol Suite and Communication

5. Protocol Data Units (PDUs)

6. Transmission Media

7. The Physical Layer
Section
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.

8. 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

9. 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

10. 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.
Section

11. 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.

12. 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

13. 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.

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

15. Copper Media
Section

16. Characteristics of Copper Media2 1 4 3
Section
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.

17. 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

18. 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

19. 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

20. 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)

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

22. 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

23. 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

24. Unshielded Twisted-Pair (UTP) Cable
Section

25. 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)

26. 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.

27. Termination — EIA/TIA-568A

28. Termination — EIA/TIA-568B

29. UTP Implementation: Straight-Through

30. UTP Implementation: CrossOver

31. 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

32. Shielded Twisted-Pair (STP) Cable
Braided or Foil Shield
Foil Shields
Section
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.

33. Coaxial Cable
Section

34. 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,

35. 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
Figure 3-17 F-Type connector
Figure 3-18 BNC connector

36. standards for Coaxial Cables
EIA standards for Coaxial Cables

37. Fiber Optic Cabling
Section

38. 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

39. 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

40. 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

41. Network Fiber Connectors
Section

42. 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

43. 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 standard
Supports speeds up to 3 Mbps
Provides device pairing over distances from 1 to 100 meters.
IEEE standard
Provides speeds up to 1 Gbps
Uses a point-to-multipoint topology to provide wireless broadband access.
Section

44. 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

45. Recourses:
L: Rehab AlFallaj, lecture notes
Cisco slides