Transcript Definition - SRMHS Computer Science

N ETWORK S YSTEMS
3.01 U NDERSTAND THE PHYSICAL COMPONENTS
OF A NETW ORK .
NETWORK TECHNOLOGY
Network
Devices
Types of
Network
Systems
Network
Technology
Transmission
Media
Linking to the
Internet
GOALS
Identify
Network
Devices
Identify
Types of
Systems
Understand
Purpose of
Network
NETWORK DEVICE
Definition:
• A device is a component used to connect
computers or other electronic devices
together so they can share files or resources.
Use:
• Performs tasks like
routing and communicating
Types of Devices:
• Router, Switch,
• Modem, Access Point
ROUTER
Definition
• A hardware device or software program that
manages the paths along which information travels
within and between networks
• A router uses the IP address to determine the
pathway.
Advantages
• Intelligent software that enables it to pass data
quickly across the network
Disadvantages
• Requires configuration
• Required for SOHO configurations
SWITCH
Definition
• A device that links multiple computers, telephones,
cameras, alarms, or networks on the same data
connection
• Provides individual connections for each host
within the local network.
• The switch uses the MAC address to determine the
pathway.
• MAC stands for Media Access Control
• The MAC address is the hardware address of the
NIC (Network Interface Card) on the end device.
• It is unique for every device.
SWITCH
Advantages
• Break-up collision domains (fewer collisions)
• Faster transfer rate than hub
• Improves the throughput of Ethernet networks
Disadvantages
• Does not create IP addresses
• No intelligent software
WIRELESS ACCESS POINT
Definition
• Joins wireless clients to a wired Ethernet
network
• Also known as “hot spots”
Advantages
• Mobility
• Network flexibility
Disadvantages
• Security vulnerability
• Signal interference and limited number of
frequencies
• Placement
MODEM
Definition
• Performs the functions of a modulator and a
demodulator
• Used with a dial-up Internet connection.
Modulator
• Enables computers to interpret data received
from a network
Demodulator
• Allows a modem to send
information formatted to be
read by network computers
END DEVICE
Definition:
A device that is either the source or the destination
of a packet on a network.
Every device must have an IP address, MAC
address and Network Interface Card.
Examples:
Computer, Printer, Server, VOIP phones, cameras
and alarms
HOST (COMPUTER)
Definition
• A computing device on a computer network
Responsibilities / Tasks / Role / Functions
• Manages tasks, communicates instructions, or
delivers specific services to other computers, or
clients, on a network
• It is the destination of a message sent through a
network.
• It includes computers, mobile phones, scanners
and printers.
Also known as…
• Computer
• Terminal
• Node
NETWORK PRINTER
Definition
• A printer that allows for multiple users to print
from remote locations of the network
• It contains its own network interface card, and
requires its own IP and MAC address.
SERVER
Definition
• A computer with the software capabilities that
provides services to other computer programs
and their users.
Types
• File Server
• DHCP & DNS
• Database
• Web
• Print
• Gaming
• Email
• Music
VOIP PHONES
Definition
• The method of delivering video and voice
communications over a computer network
Advantages
• Cheaper than the land lines
Disadvantages
• Must have electrical current
SECURITY CAMERAS
Definition
• A digital camera connected to a computer
network that allows the user to record video.
Commonly used for surveillance.
Advantages
• Powered with Ethernet cable
• Small, portable and easily accessibility
• Models can be wireless
Disadvantages
• High network bandwidth
• Requires lots of digital storage space
SECURITY AND FIRE ALARMS
Definition
• A system in place for monitoring your home
and business environment.
TYPES OF NETWORK SYSTEMS
Network Systems
• Systems that provide service to users across a
network
PERSONAL AREA NETWORK (PAN)
Service Area
• A network created around an individual’s
personal workspace
Example
• The connection between a Smart phone and a
laptop
LOCAL AREA NETWORK (LAN)
Service Area
• A network created for a home or other small
geographic area
Types
• Physical
• Wireless
Example
• A network in a school or classroom
LOCAL AREA NETWORK (LAN)
More facts
• Consists of high speed network infrastructure at
a single location used to deliver network
applications and services
• Ethernet is widely used in a LAN network.
• It has a lower cost than other transmission
media.
• It is easier to use than other transmission
media.
• It has the capability to scale up to and past
multi-gigabit speeds.
TRANSMISSION MEDIA
Definition
• Provides a path for information to be sent
from one computer to another through a
network
Types of Transmission Media:
• Coaxial cable
• Ethernet cable
• Fiber optic cable
• Wireless transmission
COAXIAL CABLE
Definition
• Cable specifically designed for carrying
an electronic signal
• Two variations- ThinNet and ThickNet
Features:
• Max Cable Length is 200 meters (ThinNet) or
500 meters (ThickNet)
• Cost (Twisted Pair < Coaxial < Fiber Optic)
• Ease of Installation (Moderately difficult to install)
• Susceptible to EMI and RFI interference
• Consists of four layers of material to reduce
interference
TWISTED PAIR CABLE
Definition
• Cable commonly used in high-speed wired
computer networks
Features:
• Cable Length (Up to 100 meters)
• Cost (Twisted pair is the cheapest)
• Ease of Installation (Easy to install)
• Susceptible to EMI and RFI interference
• Twisted pair wiring reduces interference
• Types
• Straight-through
• Crossover
• Rollover (console cable)
UNSHIELDED TWISTED PAIR (UTP)
• Found in Ethernet and phone systems
• Most common type of cable used for computer
networks.
• Used for short to medium distances (up to 100
meters)
• Not shielded against EMI or other
interference
SHIELDED TWISTED PAIR (STP)
• Found in Ethernet and phone systems
• Shielded to protect against EMI
• More costly than UTP
• Used for short to medium distances (up to 100M)
FIBER OPTIC CABLE
Definition
• Cable made of super-thin filaments of glass or
other transparent materials that can carry beams
of light
Features:
• Cable Length (Longest transmission, use of light)
• Cost (Fiber Optic is most expensive)
• Ease of Installation (Difficult to install)
FIBER OPTIC CABLE
More Features:
• Less susceptible to interference
• Data can be sent at the speed of light.
• A LASER transmitter encodes frequency signals
into pulses of light: ones and zeros are sent
through the cable.
• The receiving end of the transmission translates
the light signals back into data which can be
read by a computer.
ETHERNET STANDARDS
 The Institute of Electrical and Electronics Engineers
(IEEE) defines wired transmission in the 802.3 standard.
 Typically written as XBaseT (X= transmission speed) T=
Twisted pair cable.
 Note: The first two standards listed do not use twisted pair
cabling.






10Base2- Thin Coaxial cable ( ThinNet)
10Base5- Thick Coaxial cable ( ThickNet)
10BaseT- Original twisted pair standard
100BaseT- Fast Ethernet
1000BaseT- Gigabit Ethernet
10GBaseT- 10GB Ethernet
WIRELESS TRANSMISSION
Definition
• Able to connect computers to other computers and printers
the same way a wired network is, but without wires.
Features:
• Range (Depends on factors such as wireless card, access
point, and obstacles in between)
• Cost (Wireless price is dependent upon the complexity of
the setup.)
• Ease of Installation (Easy)
• 802.11 (a,b,g,n)
• Interference can be caused by cordless telephones and
microwaves
• Wireless security includes: WEP, WPA, and WPA2
WI-FI
 Wireless Fidelity
• The original standards for wireless networks
were put out by IEEE in 1990. These standards
are also called Wi-Fi, or Wireless Fidelity.
 SSID
• The service set identifier, or SSID, is a name
that identifies a particular Wi-Fi network to a
wireless device.
• The SSID is required, can be up to 32
characters long and is case-sensitive.
802.11 WIRELESS STANDARDS
Designation
Ratification Date
Wireless Band
Data Rate
802.11
1997
2.4 GHz
2 Mbps
802.11a
1999
5 GHz
54 Mbps
802.11b
1999
2.4 GHz
11 Mbps
802.11g
2002
2.4 GHz
54 Mbps
802.11n
2009
2.4 GHz and 5 GHz 54 Mbps to 600 Mpbs
802.11 WIRELESS SECURITY
 WEP
• WEP or Wired Equivalent Privacy uses a 64 or
128 bit key.
• WEP keys are vey insecure.
• Various attacks allow users to gain unauthorized
access to the network.
802.11 WIRELESS SECURITY
 WPA
• Wi-Fi Protected Access was designed to improve
upon WEP’s features.
• Two improvements over WEP are:
• Improved data encryption the temporal key
integrity protocol (TKIP).
• User authentication which allows only
authorized network users access.
802.11 WIRELESS SECURITY
 WPA2
• WPA2 added a new Advanced Encryption
Standard (AES) mode with mathematically
proven security.
• WPA2 offers a Pre-shared key (PSK) mode for
SOHO use.
• The PSK may be entered as a string of 64
hexadecimal digits or a passphrase.
• Shared-key WPA remains vulnerable to
password cracking attacks if users rely on a
weak passphrase.
CONNECTING TO THE INTERNET
 Internet Service Provider
• In order to access the Internet and the World
Wide Web you will need an Internet Service
Provider (ISP)
• The ISP is a company that has a permanent
connection to the Internet.
• A computer requires an ISP in order for
communication software to work
• Once again every device will need a MAC
address, IP address and Network Interface
Card.