ch.7 Flashcards
network
group of two or more computer systems linked together to exchange data and share resources
categories of computer network
1- local area network (LAN)
- use cable, radio wave, and infrared signal
- linked computer in limited geographic area
2- wide area network (WAN)
- ues long distance transmission data
- link computer system in a few mile or thousand mile
- Internet is largest in WAN
3- metropolitan area network (MAN)
- design for city
- larger than LAN, smaller than WAN
4- campus area network (CAN)
- several LAN located in various locations on college or business campus
- smaller than WAN
- use device such as router , hub , switch
5- personal area network (PAN)
- individual network own personal device
- within 32 feet
- wireless technology
6- home area network (HAN)
- wireless home network
- wire home network
- hybrid: combination between wire and wireless technology
communication device
convert data into signal to travel over medium
example of communication device
1- computer
2- modem
3- router :
- connect two or more network
- inspect source and target data package
- determine the best route to transmit data
4- switch :
- filter and forward data between node
- similar to router but work within single network
5- hub :
- join two computer in single network
- don’t manage traffic between connection
6- wireless access point
7- network interface card : expansion board or adapter that connect between computer and network
node
any device connect to network
logical address
unique name assigned to each node on network
physical address
unique numeric identify each node on network built in hardware
Physical address
Unique numeric that identifies each node on the
network built into the hardware
USB wireless network adapter
1- Plugs into a USB port
2- Usually provides an intuitive graphical user interface
(GUI) for easy configuration
USB dongle
Device inserted into a USB port that
adds additional features to the base
system
Examples: enabling network connectivity
and increasing RAM
Wireless PC card adapter
1- About the size of a credit card
2- Inserted into a slot on the side of most notebooks and
netbooks
3- Has built-in WiFi antenna that provides wireless
capability
4- LED lights that indicate whether the computer is
connected
Wireless access
point (WAP)
1- Receives and transmits
radio signals
2- Joins wireless nodes to a
wired network
Server
Computer or device with software that manages network
resources, such as files, e-mails, printers, databases
File server
1- Most common type of server
2- High-speed computer that provides program and data
files to network users
3- Contains the network operating system (NOS)
* File directories for file and resource location on the
LAN
* Automated distribution of software updates to desktop
computers on the WAN
* Internet services support
* Protection of services and data
* Access to connected hardware by authorized users
Network
administrator
1- Also called network
engineer
2- Installs, maintains,
supports computer
networks
3- Interact with users
4- Handle security
5- Troubleshoot problems
Advantages and Disadvantages of Networking
o Advantages
* Reduced hardware costs
* Application sharing
* Sharing information resources
* Data management centralization
* Connecting people
o Disadvantages
* Loss of autonomy
* Lack of privacy
* Security threats
* Loss of productivity
Wireless LAN
o Connects users through radio waves instead of wires
o Use includes networks in:
* Homes
* Hospitals
* Colleges
o Secured with a radio transmission technique that
spreads signals over a seemingly random series of
frequencies.
o Effective inside range of between 125 and 300 feet
Peer-to-Peer Networks
o In a peer-to-peer (P2P) network, all of the
computers on the network are equals or peers.
o there’s no file server
o Users also may choose to share entire
directories, entire disks, and even peripherals,
such as printers and scanners.
o P2P networks are easy to set up
o P2P networks are often used for home
networks or small businesses.
o Can be slow if there are too many users
o Security is not strong
Client/Server Networks
o Made up of one or more file servers and clients
(any type of computer)
o Client software enables requests to be sent to
the server
o Wired or wireless connections
o Do not slow down with heavy use
Intranet
o Password-protected network controlled by the
company
o Accessed only by employees
Virtual private network
o A VPN operates as a private network over a
public network
o Accessible by authorized users for quick access
to corporate information
o Uses secure, encrypted connections and special
software
LAN topologies
o Network topology
o Bus topology
o Star topology
o Ring topology
network topology
- Physical design of a LAN
o Topology resolves contention—conflict that
occurs when two or more computers on the
network attempt to transmit at the same time
o Contention sometimes results in collisions—
corruption of network data caused when two
computers transmit at the same time
Bus topology
- Practical for home or small office
- One node transmits at a time
- Terminators signify the end of the circuit
- Uses contention management—technique that
specifies what happens when a collision occurs
Star topology
- For office buildings, computer labs, and WANs
- Easy to add users
Ring topology
- For a division of a company or one floor
- Not in common use today
- Node can transmit only when it has the token—
special unit of data that travels around the ring
LAN Protocols
o Protocols (standards or rules) that enable networkconnected devices to communicate with each other
o Protocols may be implemented by hardware,
software, or a combination of the two.
o All of the communications devices in a network
conform to different protocols.
o To establish communications, modems must
conform to standards called modulation
protocols
o which ensure that your modem can communicate
with another modem even if the second modem
was made by a different manufacturer
Network Layers
1- user/application
2- presentation
3- session
4- transport: process to process delivery
5- network: host to host delivery
6- data link: hop to hop delivery
7- physical: Transmission of individual bits,
transmission mode, signal processing.
LAN technologies
o Ethernet—most-used LAN protocol
* Ethernet star networks
o Most popular versions—use twisted-pair
wiring and switches
* Sends data in a fixed-size unit called a packet
o WiFi
* Uses radio waves to provide a wireless LAN
standard at Ethernet speeds
* Needs a central access point—could be a
wireless router
* Hot spots—public wireless access locations
Point of presence (POP)
o WAN connection point used to obtain access to
the WAN
o Wired or wireless
Backbones
o High-capacity WAN transmission lines
o gigaPoP (gigabits per second point of
presence)—transfers data exceeding 1 Gbps (1
billion bits per second)
- WAN protocols
o Internet protocols
o Circuit switching
o Packet switching
o Latency
o Congestion
Internet protocols
- Transmission Control Protocol/Internet
Protocol (TCP/IP)
oProtocols that define how the Internet works - Transmission Control Protocol (TCP)
oDefines how Internet-connected computers
can exchange, control, and confirm
messages - Internet Protocol (IP)
oProvides a distinct identification to any
computer connected to the Internet: the IP
address or Internet address
Circuit switching
- Used by the public switched telephone network
to send data over a physical end-to-end circuit - Provides a direct connection between devices
Packet switching
- Used for computer communication
- Divides and sends outgoing messages as packets,
which are reassembled on receipt - More efficient and less expensive than circuit
switching
Latency
delay introduced when a given packet is
examined by many routers
Congestion
occurs when the network is overloaded,
causing some packets to be further delayed
WAN applications
o E-mail, conferencing, document exchange,
remote database access
o LAN to LAN connections connect two or more
geographically separate locations
o Transaction acquisition—the instant relay of
transaction information from a point-ofpurchase sale.
