1. Transmission Media
Lecture 1 :
CT1304 – Elham Sunbu

2. OUTLINE: Coaxial Cable Wireless Media Review Transmission media types
UTP
STP
Coaxial Cable
Wireless Media

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

4. Protocol Suites TCP/IP Protocol Suite and Communication

5. Data Encapsulation Protocol Data Units (PDUs)

6. Getting it Connected Connecting to the Network
Section
A physical connection can be a wired connection using a cable or a wireless connection using radio waves.

7. Getting it Connected Connecting to the Network
Section
Switches and wireless access points are often two separate dedicated devices, connected to a router.
Many homes use integrated service routers (ISRs),

8. Getting it Connected Network Interface Cards
Section
Network Interface Cards (NICs) connect a device to the network.
Ethernet NICs are used for a wired connection whereas WLAN (Wireless Local Area Network) NICs are used for wireless.

9. Getting it Connected Network Interface Cards
Connecting to the Wireless LAN with a Range Extender
Section
Wireless devices must share access to the airwaves connecting to the wireless access point.
Slower network performance may occur
A wired device does not need to share its access
Each wired device has a separate communications channel over its own Ethernet cable.

10. 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.

11. Purpose of the Physical Layer Physical Layer Media
Section
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. ( Focus on STP & UTP)
Fiber-optic cable: The signals are patterns of light.
Wireless: The signals are patterns of microwave transmissions. ( brief description only )

12. Fundamental Principles of Layer 1 Bandwidth
Section
Bandwidth is the capacity of a medium to carry data.
Typically measured in kilobits per second (kb/s) or megabits per second (Mb/s).
The practical bandwidth of a network is determined by a combination of factors:
The properties of the physical media
The technologies chosen for signaling and detecting network signals

13. Fundamental Principles of Layer 1 Throughput
Section
Note: There is a third measurement to measure the transfer of usable data that is known as goodput. Goodput is the measure of usable data transferred over a given period of time. Goodput is throughput minus traffic overhead for establishing sessions, acknowledgements, and encapsulation.
There are many online speed tests that can reveal the throughput of an Internet connection. The figure provides sample results from a speed test.
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.
Throughput cannot be faster than the slowest link in the path

14. Network Symbols
Repeater is used in transmission systems to regenerate analog or digital signals distorted by transmission loss.
Bridge helps to filter data traffic at a network boundary and reduce the amount of traffic on a LAN by dividing it into two segments.
10BASE-T Hub : one of several physical media specified in the IEEE standard for Ethernet local area networks (LANs)
workgroup switch is a relatively low capacity switch that serves the needs of a workgroup, or small group of workers who generally are geographically clustered
100BASE-T Hub : 100BASE-T is an enhanced form of Ethernet 10BASE-T and a network standard used for fast data transfer rates up to 100 Mbps. 
Router is a device that forwards data packets between computer networks, creating an overlay internetwork.
Hub joins multiple network devices together to form a single network segment.
Network Cloud  is a type of Internet-based computing that provides shared computer processing resources and data to computers and other  devices on demand

15. Physical Media

16. Fundamental Principles of Layer 1 Types of Physical Media
Specifications guarantee that cables and connectors will function as anticipated with different data link layer implementations.
As an example, standards for copper media are defined for the:
Type of copper cabling used
Bandwidth of the communication
Type of connectors used
Maximum distance of the media
Section
Different types of interfaces and ports available on a 1941 router

17. Copper Cabling Copper Media
Section
The most commonly used media for data communications is cabling that uses copper wires to signal data and control bits between network devices. Cabling used for data communications usually consists of a series of individual copper wires that form circuits dedicated to specific signaling purposes. Other types of copper cabling, known as coaxial cable, have a single conductor that runs through the center of the cable that is encased by, but insulated from, the other shield. The copper media type chosen is specified by the Physical layer standard required to link the Data Link layers of two or more network devices. These cables can be used to connect nodes on a LAN to intermediate devices, such as routers and switches. Cables are also used to connect WAN devices to a data services provider such as a telephone company. Each type of connection and the accompanying devices have cabling requirements stipulated by Physical layer standards. Networking media generally make use of modular jacks and plugs, which provide easy connection and disconnection. Also, a single type of physical connector may be used for multiple types of connections. For example, the RJ-45 connector is used widely in LANs with one type of media and in some WANs with another media type.

18. Copper Cabling Characteristics of Copper Media1 2 3 4
Section
Networks use copper media because it is inexpensive, easy to install, and has low resistance to electrical current. However, copper media is limited by distance and signal interference.
Data is transmitted on copper cables as electrical pulses. A detector in the network interface of a destination device must receive a signal that can be successfully decoded to match the signal sent. However, the longer the signal travels, the more it deteriorates in a phenomenon referred to as signal attenuation. For this reason, all copper media must follow strict distance limitations as specified by the guiding standards.
The timing and voltage values of the electrical pulses are also susceptible to interference from two sources:
Electromagnetic interference (EMI) or radio frequency interference (RFI) - EMI and RFI signals can distort and corrupt the data signals being carried by copper media. Potential sources of EMI and RFI include radio waves and electromagnetic devices such as fluorescent lights or electric motors as shown in the figure.
Crosstalk - Crosstalk is a disturbance caused by the electric or magnetic fields of a signal on one wire to the signal in an adjacent wire. In telephone circuits, crosstalk can result in hearing part of another voice conversation from an adjacent circuit. Specifically, when electrical current flows through a wire, it creates a small, circular magnetic field around the wire which can be picked up by an adjacent wire.
Play the animation in the figure to see how data transmission can be affected by interference.
To counter the negative effects of EMI and RFI, some types of copper cables are wrapped in metallic shielding and require proper grounding connections.
To counter the negative effects of crosstalk, some types of copper cables have opposing circuit wire pairs twisted together which effectively cancels the crosstalk.
The susceptibility of copper cables to electronic noise can also be limited by:
Selecting the cable type or category most suited to a given networking environment.
Designing a cable infrastructure to avoid known and potential sources of interference in the building structure.
Using cabling techniques that include the proper handling and termination of the cables.
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.

19. Copper Cabling Unshielded Twisted-Pair (UTP) Cable
Section
Unshielded twisted-pair (UTP) cabling is the most common networking media. UTP cabling, terminated with RJ-45 connectors, is used for interconnecting network hosts with intermediate networking devices, such as switches and routers.
In LANs, UTP cable consists of four pairs of color-coded wires that have been twisted together and then encased in a flexible plastic sheath which protects from minor physical damage. The twisting of wires helps protect against signal interference from other wires.
As seen in the figure, the color codes identify the individual pairs and wires in the pairs and aid in cable termination.
Unshielded twisted-pair (UTP) cabling is the most common networking media. UTP cabling, terminated with RJ-45 connectors, is used for interconnecting network hosts with intermediate networking devices, such as switches and routers.

20. Copper Cabling 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)

21. Copper Cabling UTPRJ45 connector

22. Copper Cabling 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.

23. Copper Cabling Termination — EIA/TIA-568A

24. Copper Cabling Termination — EIA/TIA-568B

25. Copper Cabling UTP Implementation: Straight-Through

26. Copper Cabling UTP Implementation: CrossOver

27. Copper Cabling 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

28. Copper Cabling Shielded Twisted-Pair (STP) Cable
Braided or Foil Shield
Foil Shields
Section
Shielded twisted-pair (STP) provides better noise protection than UTP cabling. However, compared to UTP cable, STP cable is significantly more expensive and difficult to install. Like UTP cable, STP uses an RJ-45 connector.
STP cable combines the techniques of shielding to counter EMI and RFI and wire twisting to counter crosstalk. To gain the full benefit of the shielding, STP cables are terminated with special shielded STP data connectors. If the cable is improperly grounded, the shield may act like an antenna and pick up unwanted signals.
Different types of STP cables with different characteristics are available. However, there are two common variations of STP:
STP cable shields the entire bundle of wires with foil eliminating virtually all interference (more common).
STP cable shields the entire bundle of wires as well as the individual wire pairs with foil eliminating all interference.
The STP cable shown uses four pairs of wires, each wrapped in a foil shield, which are then wrapped in an overall metallic braid or foil.
For many years, STP was the cabling structure specified for use in Token Ring network installations. With the decline of Token Ring the demand for shielded twisted-pair cabling also waned. However, the new 10 GB standard for Ethernet has a provision for the use of STP cabling which is providing a renewed interest in shielded twisted-pair cabling.
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.

29. Coaxial Cable As shown in the figure, coaxial cable consists of:
Copper Cabling:
Coaxial Cable
As shown in the figure, coaxial cable consists of:
A copper conductor used to transmit the electronic signals
Conductor is surrounded by an insulating layer of flexible plastic insulation.
Insulating material is surrounded in a woven copper braid, that acts as the second wire in the circuit and as a shield for the inner conductor.
Entire cable is covered with a cable jacket; protects it from physical damage.

30. Wireless Media Wireless Media
IEEE 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

31. Recourses: Rehab AlFallaj , lecture notes
Asmaa AlOsaimi, lecture notes
Cisco slides
Crossover and Straight Through Cables: http: //
Straight-through and Cross-over Cable theory:
How to make CAT5 Ethernet Cable - Straight Through & Crossover: