Networks
In a computer network,
connected computers:
ü Work together
ü Are interdependent
ü Exchange data
with each other
Bandwidth: the transmission
capacity of a network. It is stated in bits per second (bps)
Broadband: Network transmission
capacities ranging from approximately 1 million bps (megabits/second) up to several
terabits / second
Types of Computer Networks
v Local Area Networks (LAN)
connects two or more devices in a limited
geographical region(usually within the same building) so that every device on
the network can communicate with every other device.
Ø Speed
Ø Distance
Ø Cost
Types of Computer Networks
v
Local Area Networks (LAN)
- Every device in the LAN has a network
interface card (NIC)
- NIC allows the device to physically
connects to the LAN’s
communication medium
- Network Server : contains various software (operating
system)
and data for the network
Types of Computer Networks
v
Wide Area Networks (WAN)
- covers a large geographical area and
have large capacity
- Provided by telecommunication companies
- WANs also contain routers
Router: a communication processor that routes
messages from LAN to the Internet , across several connected LANs
Types of Computer Networks
v
Enterprise Networks
- A
network, encompassing an organization, composed of interconnected multiple
LANs and WANs
- Backbone Network:
high-speed central network
to which multiple smeller
networks connect
Network Fundamentals
Networks transmit information with two types of signals:
1. Analog Signals
Continuous waves that transmit information by altering the
characteristics of the
waves
Have two parameters : amplitude (higher the wave) and frequency (more closely packed)
2. Digital Signals
Discrete pulses that are either ON or OFF ,
representing a series of
bits (0s and 1s)
Modem (modulator-demodulator)
Converts digital signals to analog signals and vice versa
D → A = Modulation
A → D = Demodulation
Communication Media and
Channels
Pathways for communicating data
from one location to another
- Wireline
Media (Cable)
v
Twisted-Pair Wire
v
Coaxial Cable
v
Fiber-optic Cable
- Wireless
Media (Broadcast)
v
Microwave
v
Satellite
v
Radio
v
Infrared
Transmission Technologies
Digital Subscriber Line (DSL)
A technology that provides
high-speed
transmission of digital data over
existing
copper telephone lines
- OmantTel
ADSL offers bandwidth up to 40 Mbps
Asynchronous Transfer Mode
(ATM)
- Can
transmit up to 2.5 Gbps
- Requires
fiber-optic cables
- More
expensive than DSL
Network Protocol
Set of rules and procedures that
govern transmission across a network
Ethernet
- A common LAN
protocol
Transmission Control Protocol /
Internet Protocol (TCP/IP)
- The
Protocol of the Internet
Packet Switching
Technology that breaks blocks of
text into small, fixed bundles of data
and routes them in the most
economical way through any available
communication channel
Types of Network Processing
Distributed Processing
Divides processing work among two
or more computers
Client-Server Computing
Links two or more computers in an
arrangement in which some
machines, called Servers,
provide computing services of users PCs,
called Clients.
Peer-to-peer (P2P) processing
A type of client-server
distributed processing where each computer acts as both a client and a server
Microsoft SharePoint
The Internet and the World Wide Web
The Internet (“the Net”)
Grew out an experimental
project of the Advanced Research
Project Agency (ARPA) of USA
DoD in 1969 [ARPAnet)
v
Intranet
v
Extranet
Internet Service Provider (ISP)
A telecommunication company
that offers Internet connections for
ISPs connect to one another
through NAPs
Addresses
on the Internet
Internet Protocol Address (IP) Address)
An assigned address that distinguishes each computer on the
Internet from all other computers
135.62.128.91
The
Internet Corporation for Assigned Names (ICANN)
Responsible for coordinating IP addresses throughout the world
ICANN accredits certain companies called registrars to register
names (called Domain Names) that
are equivalent to the IP
address
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