Why using Network
• Networks help users on the network to share the resources and in
communication. Can you imagine a world now without emails,
online news papers, blogs, chat and the other services offered by
the internet?
• The following are the important benefits of a computer network.
• File sharing: Networking of computers helps the users to share data
files.
• Hardware sharing: Users can share devices such as printers,
scanners, CD-ROM drives, hard drives etc.
• Application sharing: Applications can be shared over the network,
and this allows to implement client/server applications
• User communication: Networks allow users to communicate using
e-mail, newsgroups, and video conferencing etc.
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What is a Network?
• A network is a group of computers or devices
connected together to share the resources like file,
printer, services etc.
• A typical network contains users working at
workstations (also known as client), running client
operating systems like Windows 7 and store their files
on a central server.
• The server computer has more resources like memory,
disk space and more processing power compared with
client computers. The server machine also run an
Operating System, which has more processing
capabilities compared with the client machine.
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Network Topologies
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Ring Network Topology
A ring topology sends messages clockwise or counterclockwise
through the shared link.
A failure in any cable or device breaks the loop and can take
down the entire network.
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Bus Network Topology
A bus topology uses a single communication backbone for all
devices.
Bus networks work best with a limited number of devices. If
more than a few dozen computers are added to a network bus,
performance problems will likely result.
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Star Network Topology
A star topology typically uses a network
hub or switch and is common in home
networks.
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Tree Network Topology
This diagram illustrates the tree network topology. A tree topology
integrates the star and bus topologies in a hybrid approach to improve
network scalability.
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Mesh Network Topology
A mesh topology provides redundant communication
paths between some or all devices (partial or full mesh).
Mesh topologies involve the concept of routes.
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LAN, MAN and WAN
• Local Area Network (LAN) is a network, which is
limited to a single building, college campus etc.
• A Wide Area Network (WAN) spans over multiple
geographic locations, which is composed of
multiple LANs.
• A Metropolitan Area Network (MAN) refers to a
network, which is located in a city or
metropolitan area. If an organization has multiple
offices in a city, the term that refers the network
is called MAN.
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Types of Networks
• Peer-to-Peer (P2P)
• A Peer-to-Peer network has no dedicated servers.
• Number of workstations are connected together
for the purpose of sharing information or devices.
• All the workstations are considered as equal. Any
one computer can act as client or server at any
instance.
• This network is ideal for small networks where
there is no need for dedicated servers, like home
network or small business.
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Peer to Peer Network
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P2P Advantages
• 1) It is easy to install and so is the configuration of computers on
this network,
2) All the resources and contents are shared by all the peers, unlike
server-client architecture where Server shares all the contents and
resources.
3) P2P is more reliable as central dependency is eliminated. Failure
of one peer doesn’t affect the functioning of other peers. In case of
Client –Server network, if server goes down whole network gets
affected.
4) There is no need for full-time System Administrator. Every user is
the administrator of his machine. User can control their shared
resources.
5) The over-all cost of building and maintaining this type of network
is comparatively very less.
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P2P Disadvantages
1) In this network, the whole system is decentralized thus it is
difficult to administer. That is one person cannot determine the
whole accessibility setting of whole network.
2)
Lack of security in this system. Viruses, spywares, trojans, etc
malwares can easily transmitted over this P-2-P architecture.
3)
Data recovery or backup is very difficult. Each computer should
have its own back-up system
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Client-Server Networks
• The client/server model consists of high-end
servers serving clients continuously on a
network, by providing them with specific
services upon request.
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Client-Server Advantage
• Centralized - Resources and data security are
controlled through the server.
• Scalability - Any or all elements can be replaced
individually as needs increase.
• Flexibility - New technology can be easily integrated
into system.
• Accessibility - Server can be accessed remotely and
across multiple platforms.
• security - Resources and data security are controlled
through the server.
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Client-Server Advantage
• Network will run far better as data and resources are
handled by a dedicated machine
• Backup - as all data is stored centrally it is easy to
backup
• Support and management - as the server controls
the majority of settings on the network etc, the job
of support is far easier than P2P.
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Client-Server Disadvantages
• More expensive than a peer-to-peer network
you have to pay for the server cost.
• When the server goes down or crashes all the
computers connected to it become
unavailable to use.
• When everyone tries to do the same thing it
takes a little while for the server to do certain
tasks.
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Client/Server
• NOS - Network Operating System that includes
special functions for connecting computers and
devices into a Local-Area-Network(LAN). Some
operating systems, such as UNIX and the Mac OS,
have networking functions built in. The term
network operating system, however, is generally
reserved for software that enhances a basic
operating system by adding networking features.
Novell Netware, Artisoft's LANtastic, Microsoft
Windows Server, and Windows NT are examples
of an NOS.
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Network Terms
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Client
Server
NOS (Network Operating System )
NIC (Network Interface Card)
Host
Node
Segment
Backbone
Topology
Protocol
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Network Terms
• Packet
• Addressing
• Transmission media
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How Networks Are Used
• Network services
– Functions provided by a network
– E-mail
– Printer sharing
– File sharing
– Internet access and Web site delivery
– Remote access capabilities
– Voice (telephone) and video services
– Network management
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File and Print Services
• File services
– Capability of server to share data files,
applications and disk storage space
• File server
– Provides file services
• File services provide foundation of networking
• Print services
– Share printers across network
– Saves time and money
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Access Services
• Allow remote user network connection
• Allow network users to connect to machines
outside the network
• Remote user
– Computer user on different network or in different
geographical location from LAN’s server
• Network operating systems include built-in
access services
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Communications Services
• Mail server
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Computer responsible for e-mail storage and transfer
Intercept spam
Handle objectionable content
Route messages according to rules
Provide Web-based client for checking e-mail
Notify administrators or users if certain events occur
Schedule e-mail transmission, retrieval, storage,
maintenance
– Communicate with mail servers on other networks
• Mail server runs specialized mail server software
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Internet Services
• Web server
– Computer installed with appropriate software to
supply Web pages to many different clients upon
demand
• Other Internet services
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File transfer capabilities
Internet addressing schemes
Security filters
Means for directly logging on to other Internet
computers
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Becoming a Networking Professional
• Job market
– Many job postings for computer professionals
– Expertise levels required vary
• To prepare for entering job market:
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Master general networking technologies
Select and study areas of interest
Hone communication and teamwork skills
Stay abreast of emerging technologies
Consider professional certification
Get to know others in your field
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Mastering the Technical Challenges
• Skills to acquire
– Installing, configuring, troubleshooting network
server and client hardware and software
– Understanding characteristics of transmission
media
– Understanding network design
– Understanding network protocols
– Understanding how users interact with network
– Constructing a network with clients, servers,
media, and connectivity devices
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Mastering the Technical Challenges
• Pick one or two areas of concentration
• Specialties currently in high demand
– Network security
– Convergence
– In-depth knowledge about one or more NOSs
• UNIX, Linux, MAC OS X Server, Microsoft Windows Server
2008 R2
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Network management
Wireless network design
Configuration of routers and switches
Centralized data storage and management
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Developing Your “Soft Skills”
• Soft skills
– Not easily measurable
– Important to networking projects
• Examples of soft skills
– Customer relations
– Oral and written communications
– Dependability
– Teamwork
– Leadership abilities
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Pursuing Certification
• Certification process
– Mastering specific material
• Hardware system, operating system, programming language,
software application
– Proving mastery
• Pass exams
• Professional organizations
– CompTIA
• Network+
• Vendors
– Microsoft , Cisco
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Pursuing Certification (cont’d.)
• Benefits
– Better salary
– Greater opportunities
– Professional respect
– Access to better support
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