Networks: Communicating & Sharing Resources

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24 Οκτ 2013 (πριν από 3 χρόνια και 10 μήνες)

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Networks: Communicating &
Sharing Resources

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Objectives


Understand basic networking concepts.


Discuss the advantages and
disadvantages of networks.


Distinguish between peer
-
to
-
peer
(P2P) and client/server local area
networks (LANs).


Define topology and understand how
the three LAN topologies differ.

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Objectives


Explain the importance of network
protocols.


Name the most widely used LAN
protocol and its versions.


Identify the special components of a
wide area network (WAN) that
differentiate it from a LAN.

3

Objectives


Contrast circuit
-
switching and packet
-
switching networks and explain their
respective strengths and weaknesses.


Identify the options, components,
configuration, and maintenance of a
home area network (HAN).

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Network Fundamentals


A
network

links multiple computer
systems to enable them to share data
and resources.


Categories of computer networks for
business and organizations:


Local area network (LAN)


Wide area network (WAN)

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Network Fundamentals

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Network Fundamentals


LAN


Uses cables, radio waves, or infrared signals


Links computers in a limited geographic area


WAN


Uses long
-
distance transmission media


Links computer systems a few miles or
thousands of miles apart


The Internet is the largest WAN

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Network Fundamentals


Communication devices
convert data into signals
to travel over a medium.


Computers


Modems


Routers


Switches


Network interface cards
(NICs)


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Network Fundamentals


A
node

is any device connected to a
network.


Network interface card (NIC)


An expansion board or adapter that
provides a connection between the
computer and the network


Notebook computers have wireless NICs

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Network Fundamentals


Routers



Connect two or more networks


Determine the best route to transmit data


Switches



Filter and forward data between nodes


Are similar to routers but work within a
single network

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Network Fundamentals


Wireless access
point (WAP)


Receives and transmits
radio signals


Joins wireless nodes to a
wired network


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Network Fundamentals


File server


High
-
speed computer that provides
program and data files to network users


Contains the
network operating system
(NOS)


File directories for file and resource location


Computerized software update distribution


Internet services support


Protection of services and data


Access to connected hardware by authorized
users

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Advantages &

Disadvantages of Networking


Networking


Advantages


Hardware cost reduction


Sharing of information, data, and applications


Data management centralization


Linking of people


Disadvantages


Loss of autonomy


Lack of privacy


Security threats


Loss of productivity

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Peer
-
to
-
peer (P2P) networks


Share files without a file server


Are easy to set up


Are best used for home or small offices
with no more than 10 computers


Do not require a network operating system


Can be slow if there are too many users


Security is not strong

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Local Area Networks

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Peer
-
to
-
peer (P2P) networks

Local Area Networks


Client/server networks


Made up of one or more file servers and
clients
(any type of computer)


Client software enables requests to be sent
to the server


Wired or wireless connections


Do not slow down with heavy use


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Local Area Networks


Virtual private network


Operates over the Internet


Is accessible by authorized users for quick
access to corporate information


Uses secure, encrypted connections and
special software

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Local Area Networks

Local Area Networks


LAN topologies


Network topology
is the physical
design of a LAN.


Topology resolves
contention
, the
conflict that occurs when two or more
computers on the network attempt to
transmit at the same time.

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LAN topologies


Bus topology


Practical for home or small office


One node transmits at a time


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

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Local Area Networks

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Local Area Networks

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Local Area Networks

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Local Area Networks


LAN protocols


Protocols

are the standards used by
networks to permit communication
between network
-
connected devices.


A network’s

protocol suite

contains the
protocols of the network and specifies its
network architecture, or how the network
works.

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Local Area Networks

Local Area Networks


LAN protocols


Network layers

divide architecture for
separate treatment.


Each network layer can operate and be
governed by its own protocols.


The vertical arrangement of network layers is
called a
protocol stack
.

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Local Area Networks


LAN protocols


LAN technologies


Ethernet

is the most
-
used LAN protocol.


The most popular versions are Ethernet star
networks, which use twisted
-
pair wiring and switches.


Wi
-
Fi


Uses radio waves to provide a wireless LAN
standard at Ethernet speeds


Needs a central access point, which could be a
wireless router

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Wide Area Networks


Point of presence (POP)



WAN connection point used to obtain
access to the WAN


Wired or wireless


Backbones



High
-
capacity WAN transmission lines


gigaPoP (gigabits per second point of
presence)
transfers data exceeding 1 Gbps

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Wide Area Networks


WAN protocols


Internet protocols


Transmission Control Protocol (TCP)


Defines how Internet
-
connected computers can
exchange, control, and confirm messages


Internet Protocol (IP)


Provides a distinct identification to any computer
connected to the Internet: the
IP address


TCP/IP


Together, they define how the Internet works.

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WAN protocols


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 upon receipt


More efficient and less expensive than circuit
switching

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Wide Area Networks

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Wide Area Networks

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Wide Area Networks

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Wide Area Networks

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Wide Area Networks

Wide Area Networks


WAN applications:
E
-
mail,
conferencing, document exchange,
remote database access


LAN to LAN Connections


Transaction Acquisition

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Home Networks


Wired Home Networks


Ethernet networks link computers with a
switch or router.



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Home Networks


Wireless Home Networks


Wi
-
Fi is the wireless standard.


Uses radio signals


Communicates through network access points


Needs wireless adapter or router





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Home Networks


Setting up a home network


Planning


Select technology


Purchase equipment and firewall software


Configuring a wired network


Connect each computer to the router


Plug printer, scanner, etc., into a computer


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Home Networks


Setting up a home network


Configuring a wireless network


Connect each node to wireless router with a
wireless adapter


Connect DSL or cable modem to wireless router


Maintenance and support


Minimal maintenance required


Unplug power source from router and other
peripherals and restart computer to correct
problems

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Home Networks


Future of home networking


Control household appliances.


Protect homes with security systems.


Manage home network events through
central control units in new homes.


Utilize wireless systems.

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Summary


Computer networks of two or more
linked computers share resources and
exchange data.


The two main types of networks are
local area networks (LANs) and wide
area networks (WANs).


There are advantages and
disadvantages to using a computer
network.

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Summary

40


Two main categories of LANs are peer
-
to
-
peer (P2P) and client/server.


Topologies of a LAN include the bus
topology, the ring topology, and the
star topology.


Protocols define the manner in which
network devices communicate.

Summary


The Ethernet is the most popular LAN
protocol.


Distinguishing components of a WAN,
as compared with a LAN, are its point
of presence (POP) and backbones.


WAN connections may be made
through analog telephone calls or
digital hookups.

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Summary


The technologies on which WAN
protocols are based use either circuit
switching (PSTN) or packet switching
(the Internet).


Wired home networks use Ethernet
cable, and wireless home networks
rely on Wi
-
Fi radio signals.


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