Chapter 1 An Introduction to Networking

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3 Δεκ 2013 (πριν από 3 χρόνια και 10 μήνες)

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Chapter 1

An Introduction to Networking

Collected and Compiled

By JD Willard

MCSE, MCSA, Network+,

Microsoft IT Academy Administrator

Computer Information Systems Instructor

Albany Technical College

Attention: Accessing Demos


This course presents many demos.


The Demos

require that you be logged in to the Virtual
Technical College web site when you click on them to run.


To access and log in to the Virtual Technical College web site:


To access the site type
www.vtc.com

in the url window


Log in using the username: CIS 1140 or ATCStudent1


Enter the password: student (case sensitive)



If you should click on the demo link and you get an Access
Denied it is because you have not logged in to vtc.com or you
need to log out and log back in.


If you should click on the demo link and you are taken to the
VTC.com web site page you should do a search in the search
box for the CompTIA Network+ (2009 Objectives) Course and
run the video from within that page.


Objectives


List the advantages of networked
computing relative to standalone
computing


Distinguish between client/server and
peer
-
to
-
peer networks


List elements common to all client/server
networks

Why Use Networks?


Network:

group of computers and other devices that are
connected by some type of transmission media


Commonly connected devices include computers, laptops,
mainframe computers, terminals, printers, fax machines,
PDAs, cell phones, and various data storage devices


Advantages of networks are that they actually save
organizations money by allowing them to:


Centralize Administration


Consolidate (centralize) data storage


Share data and peripheral devices like printers


Increase internal and external communications


Increase productivity and collaboration

Networking Basics
Demo

Types of Networks


Models vary according to:


Computer positioning


Control levels over shared resources


Communication and resource sharing
schemes


Network models


Peer
-
to
-
peer


Client/server


Network Models
Demo

Peer
-
to
-
Peer Networks


Direct computer communication


Equal authority


Individual resource sharing


Users act as their own administrator


May share resources


May prevent access to resources


Traditional model


Two or more general purpose computers:


Capable of sending and receiving information to and from every
other computer


Environments


Small home or office


Large networks using the Internet


Gnutella,
Bitcoin
, original Napster


BitTorrent

software


Peer
-
to
-
Peer Networks (cont’d.)


Resource sharing
method


Modify file sharing
controls


User responsibility


Lack centralized control


Access may not
be uniform or
secure



Resource sharing on a simple peer
-
to
-
peer network

Peer
-
to
-
Peer Networks (cont’d.)


Advantages


Simple configuration


Computers are in same general area


No dedicated server or hierarchy


Less expensive


Compared to other network models


Disadvantages


No centralized storage


Not flexible


Difficult to expand (not scalable)


Not necessarily secure


Decentralized security model


Security is maintained on each individual computer


Not practical for large installations


Usually 10 or fewer workstations

Peer to Peer vs. Server Centric
Demo


Client/Server Networks


Computer roles


Server


Central computer


Facilitates communication and resource sharing between clients


Clients


Personal computers


Also known as workstations


Run local applications


Store data locally


Use server shared applications, data, devices


Use server as intermediary


Central resource sharing controlled by server


Centralized security model


Sharing data, storage space, devices


No direct sharing of client resources


Communication


Switches or routers


Client/Server Networks (cont’d.)


Server requirement


To function as a Server, a computer must be running a network
operating system (NOS)


Manages client data, resources


Ensures authorized user access


Controls user file access


Restricts user network access


Dictates computer communication rules


Supplies application to clients


Server examples


UNIX, Linux, Microsoft Server 2008 R2, MAC OS X Server


Server features relative to clients


More memory, processing, storage capacity


Equipped with special hardware


Provides network management functions


Data Redundancy


Client/Server Networks (cont’d.)

Resource sharing on a client/server network


Advantages relative to peer
-
to
-
peer
networks


User credentials can be assigned
in one place


Multiple shared resource access
centrally granted to a single user
or groups of users


Centralized backup


Central problem monitoring,
diagnostics, correction capabilities
from one location


Servers are optimized to handle
heavy processing loads and
dedicated to handling requests
from clients, enabling faster
response time


Because of their efficient
processing and larger disk
storage, servers can connect
more than a handful of computers
on a network


More scalable


Supports many users





Disadvantages relative to peer
-
to
-
peer network


Complex design and maintenance


Requires extensive advanced planning


Server operating systems are expensive


Client Server and Peer
-
to
-
Peer Networks (2:47)

LANs, MANs, and WANs


LAN (local area network)


Network confined to a relatively
small space such as a building
or an office


1980s


LANs became popular as
peer
-
to
-
peer based


Today


Larger and more complex
client/server network


High speed networks


Typically Ethernet


Star
-
wired networks
using fiber optic cables,
twisted
-
pair cables, and
wireless

Interconnected LANs

LANs and WANs
Demo


LANs, MANs, and WANs


MAN (metropolitan area network)


Sometimes called a CAN (campus area
network)


Larger than a LAN


Generally covers campuses or office
complexes


Connects clients and servers from multiple
buildings


Uses different transmission media and
technology than LAN


LANs, MANs, and WANs (cont’d.)


WAN (wide area network)


Connects two or more
geographically distinct
LANs or MANs (states,
countries, continents)


Uses different transmission
methods and media than
LAN


Communication circuits
connected by routers


Network connection


Separate offices in
same organization


Separate offices in
different organizations

A simple WAN

Elements Common to

Client/Server Networks


Client


Network computer requesting resources or services
from another network computer


Client workstation human user


Client software installed on workstation


Server


Network computer managing shared resources


Runs network operating software that can manage
not only data, but also users, groups, security, and
applications on the network


Workstation


Personal computer


May or may not be connected to network

Network Requirements
Demo


Elements Common to

Client/Server Networks (cont’d.)


NIC (network interface card)


Device inside computer


Connects computer to
network media


Allows communication
with other computers


NOS (network operating
system)


Server software


Enables server to manage
data, users, groups,
security, applications, and
other networking functions

A NIC (network interface card)

Elements Common to

Client/Server Networks (cont’d.)


Host


Computer


Enables network resource sharing by other
computers (hosts resources)


Identified by unique network address


Node


Client, server, or other device connected to a
network


Connectivity device


Allows multiple networks or multiple parts of one
network to connect and exchange data

Elements Common to

Client/Server Networks (cont’d.)


Segment


Group of nodes


Uses same
communications
channel for traffic


Backbone


Connects segments
and significant
shared devices


“A network of
networks”

A LAN backbone


Topology


Computer
network
physical
layout


Ring, bus,
star or
hybrid
formation


Common network topologies
Demo

Network Topologies (4:52)

Elements Common to

Client/Server Networks (cont’d.)


Protocol


Standard method or format for communication
between networked devices


Packet


Distinct data units exchanged between nodes


Addressing


Scheme for assigning unique identifying
number to every node on the network

Examples of network transmission media


Transmission media


Means through
which data is
transmitted and
received


Summary


A network is a group of computers and other
devices that are connected by some type of
transmission media


In a peer
-
to
-
peer network, every computer can
communicate directly with every other computer


A client/server network uses a server to enable
clients to share data, data storage space, and
devices


A LAN is confined to a relatively small space,
such as a building or office

Summary


A MAN is larger than a LAN and connects
clients and servers from multiple buildings


A WAN connects two or more
geographically distinct LANs or MANs


Elements common to client/server
networks: client, server, workstation, NIC,
NOS, host, node, connectivity device,
segment, backbone, topology, protocol,
data packets, addressing, and
transmission media

The End