transmission media
DESCRIPTION
What is transmission media and its type.....TRANSCRIPT
Chapter 3 11
Transmission Media
Chapter 3
Chapter 3 2
Chapter Objectives
Discuss characteristics of cables List the various types of copper wired cables Discuss fiber optic cables Explain wireless transmission media
Chapter 3 3
Recall - I
Topology is a pattern of computer devices and describes the way in which these devices are connected
The disadvantages of bus topology are: Entire network gets affected if main cable breaks Terminators are required at both ends of backbone
cable Difficult to detect the faulty device Limited number of devices can be attached Heavy traffic degrades performance
Chapter 3 4
Recall - II
The advantages of ring topology are: Easier to mange as compared to Bus network Handles large volume of traffic Very reliable and offers great speed Provides a good communication over a long distance No terminators are required
Types of mesh topology are: Full mesh topology Partial mesh topology
Chapter 3 5
Characteristics of Cables Segment Length – Length of single wire Attenuation – Indicates loss of signal Bandwidth – Amount of data carried by cable Number of Segments – Maximum number of
segments in network Cost – Copper cables are cheapest, fiber optic cables
are expensive Interference susceptibility and crosstalk – Defines
concept of electronic interference on cables Crosstalk- Explains the concept of interference
generated when magnetic fields or current of one cable affects electrical currents of other cable
Chapter 3 6
Selection of cable
Analyze the present and future data transmission speed required by the application.
Determine if high density graphics are required in future.
Consider the architecture of the network to be designed.
Determine whether you want to use copper cable or fiber optic cable.
See for the dispersion of devices in the network, how widely they are spaced. (Check for the suitable price of cable.)
Check for backbone or a lobe to a LAN node.
Chapter 3 7
Types of cables Copper medium is the cheapest mode of data transfer
Types of cables
Coaxial cable Twisted pair cables
Chapter 3 8
Coaxial cable Consist of a solid copper core surrounded by an
insulator mainly made up of Poly Vinyl Chloride (PVC) or Teflon
Coaxial cables are less prone to interference (both internal and external)
Chapter 3 9
Types of Coaxial cable Coaxial cables are mainly divided into four
categories
Types of Coaxial cables
RG58 RG8 RG6 RG59
Chapter 3 10
RG58
Maximum segment length is 200 meters Interference protection is better than twisted pair
cables Offers resistance of 50 ohms BNC-T connector is used to connect this cable Used in thinnet (10BASE2) network Mostly used in changing environments Easy to add/remove devices form the network using
RG58 cable Cheapest form of coaxial cable
Chapter 3 11
RG8
Maximum segment length is 500 meters Interference protection is good compared to any
copper cable Offers resistance of 50 ohms AUI and Vampire Tap connector is used to connect
this cable Used in 10BASE5 network Expensive than RG58 Disadvantage is rigidness due to which it is only
used as a backbone
Chapter 3 12
RG6
Broadband quad-shielded cable that offers an impedance of 75 ohms
Provides lower attenuation characteristics
Useful in cable TV, CCTV and satellite dish antenna
Covers distance up to 1500 feet (450m approx)
Chapter 3 13
RG59
Solid conductor is surrounded by a foam polyethylene dielectric
Offers impedance of 75 ohm and used with BNC connector
Useful in security camera, cable TV and home theatre
Covers a distance up to 1000 feet (300m approx)
Has a higher attenuation as compared to other coaxial cables
Practical
To cut the sheath of different coaxial cables and see the different layers inside the cable.
Chapter 3 14
Chapter 3 15
Twisted Pair Cables A pair of cables twisted around each other forms a twisted
pair cable.
Twisted Pair cables
Unshielded Twisted Pair
Shielded Twisted pair
Chapter 3 16
UTP Cables - I
Pair of unshielded wires wound around each other
Cheapest form of cables available for networking purpose
Highly used in LAN environments
Easy to install Easily gets affected by EMI and
RFI
Chapter 3 17
UTP Cables - I
Maximum cable length – 100m Bandwidth – 100 Mbps Connector – RJ45 Bend Radius – 360 degree/feet Resistance – 50 ohm Signal Transmission Mode - Baseband
Chapter 3 18
UTP Cable Types-I
Cat 7
Cat 6
Cat 5e
Cat 5
Cat 4
Cat 3
Cat 2
Cat 1
UTP
Chapter 3 19
UTP cable types-II
CAT1 – telephone cable CAT2 – 4 Mbps CAT3 – 10 Mbps, 16 MHz (10 Base T) CAT4 – 16 Mbps, 20 MHz (Token Ring) CAT5 – 100 Mbps, 100 MHz (100 Base T) CAT5e – 1000 Mbps, 100 MHz (22 Gauge) CAT6 – 1000 Mbps, 250 MHz (24 Gauge) CAT6a - 10GBase – T, 500 MHz CAT7 – 10GBase – T, 600 MHz CAT7a - 40 Gigabit Ethernet ,1000 MHz
Chapter 3 20
STP Cables
Pair of wires wound around each other is placed inside a protective foil wrap
Better protection from EMI, RFI and crosstalk as compared to UTP
STP is cheaper than fiber optic cable but costlier than UTP
Chapter 3 21
Types of STP Cables
CAT5e – Operates at 350 MHz and carries data up to 1000 Mbps
150 Ohm Shielded Cable – Operates at 16 MHz
Practical
Cutting the sheath of twisted pair cable and seeing the various pairs of the cable
Chapter 3 22
Chapter 3 23
Case Study 1
The Mumbai branch of MoneyMaker bank has multiple departments, which are on different floors in the same building. Each department is interconnected using UTP cables. John, the network administrator has set up a client server environment and has used a star topology. The employees of the bank are unable to transmit data and information from one department to another in an efficient manner
Chapter 3 24
Problem
Data and information cannot be transmitted between the departments efficiently
Chapter 3 25
Suggested Solution
The problem is caused due to EMI emitted by the electrical transformers. John should use STP cables to interconnect the different departments located on each floor as STP provides better protection from EMI. The computers inside each department can be interconnected using UTP cables.
Chapter 3 26
Use CBT to explain fiber optic cable
Chapter 3 29
Fiber Optic Cable Characteristics Bandwidth – Carries large amount of data ranging
from 100 Mbps to 1 Gbps Segment Length – Transmits data signals over
larger distance (2 – 100 K.M.) Interference – No electric signals pass through
these types of cables thus providing security. Used in areas that are highly susceptible to noise, e.g. near TV towers, radio stations and electric transformer.
Chapter 3 33
Multi Mode Fiber Optic cable - II Multiple modes of light signals can be
propagated through it Transmits data over short distances Use LEDs as source of light Used to transmit two or more signals using a
single fiber Speed is less as compared to single mode
fiber optic cable Widely used now a days
Chapter 3 34
Fiber Optic Cable Connectors -I Connectors depend on the different kinds of
light emitting sources (LED and Laser) and light sensors used
Straight Tip (ST) – A popular connector used with fiber optic cables and used in gigabit Ethernets or backbone
Subscriber Connector (SC) – A type of low cost connector used in 100 Base-FX fiber optic networks and can be pushed into the device and removed by pulling out.
Chapter 3 35
Fiber Optic Cable Connectors -II Medium Interface Connector (MIC) – like SC
and are used in the FDDI architecture Sub Miniature Type A (SMA) – looks similar
to ST but uses a threaded outer shell. Fiber Jack – Attaches two fibers in snap lock
connector
Chapter 3 39
Media Comparison
Characteristics UTP STP Coaxial Cables Fiber Optic Cables
Bandwidth 10 Mbps – 100 Mbps 10 Mbps – 100 Mbps 10 Mbps 100 Mbps - 1 Gbps
Maximum cable segment 100 meters 100 meters 200 – 500 meters 2 k.m. – 100 k.m.
Interference rating Poor Better than UTP Better than twisted pair wires
Very good as compared to any other cable
Installation cost Cheap Costly than UTP Costly than twisted pair wires
Most costly to install
Bend radius 360 degrees / feet 360 degrees / feet 360 degrees / feet or 30 degrees / feet
30 degrees / feet
Security Low Low Low High
Chapter 3 40
Wireless Medium
Unguided form of transmission medium Transmitters and receivers are used to send and
receive signals Involves use of electromagnetic waves such as
microwave, infrared, radio waves etc. Wireless medium is useful in connecting large
geographical areas
Chapter 3 47
Summary – I
Networking hardware involves all peripheral devices, interface cards and other components such as cables and wires that are used to establish network connection
All cables have certain characteristics such as segment length, bandwidth, crosstalk, attenuation, interference susceptibility, cost and number of segments
Different types of medium are available for transmitting data over the network such as copper medium, fiber optic medium and wireless medium
Copper medium includes coaxial cables and twisted pair cables
Chapter 3 48
Summary – II
Twisted pair cable consists of a pair of cables that is twisted around each other
Two types twisted pair cable are STP and UTP Crosstalk is a phenomenon in which signals of one wire
interfere with the signals transmitted over the other wire To avoid crosstalk, a pair of wires wound around each
other and each pair is placed inside a protective foil wrap Types of UTP cables are Cat 1, Cat 2, Cat 3, Cat 4, Cat
5, Cat 5e, Cat 6, CAT6a and Cat 7 STP cable types include Cat 5e and 150 ohm shielded
cable
Chapter 3 49
Summary – III
Coaxial cables consist of a solid copper core that is surrounded by an insulator which is again covered by a mesh like ground wire and an outer cover known as a sheath
Thinwire or RG-58 cable is approximately 0.64 cm in diameter and is used in constantly changing environments
BNC connector is used to connect devices to the thinnet coaxial cable network
RG-8 cable is approximately 1 cm in diameter and used as a backbone cable
Chapter 3 50
Summary – IV
For RG-6 cable, the center conductor is 1.05 mm in diameter and for RG-59 cable is 0.86 mm
A fiber optic cable consists of a centre glass core that is surrounded by a glass cladding, Kevlar fibers and an outer sheath material
LEDs and lasers are used to transmit light signals through the fiber optic cables
There are two types of fiber optic cables available namely single mode and multi mode
Chapter 3 51
Summary – V
The primary types of connectors used to connect fiber cables are ST, SC, SMA, Fiber Jack and MIC
In wireless medium, signals are transmitted through air and space using radio and satellite networks