1. Why using Network
Networks help users on the network to share the resources and in communication. Can you imagine a world now without s, 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 , newsgroups, and video conferencing etc.

2. 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.

3. Network Topologies

4. 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.

5. 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.

6. Star Network Topology
A star topology typically uses a network hub or switch and is common in home networks.

7. 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.

8. 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.

9. 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.

10. 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.

11. Peer to Peer Network

12. 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.

13. P2P Disadvantages
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.
Lack of security in this system. Viruses, spywares, trojans, etc malwares can easily transmitted over this P-2-P architecture.
Data recovery or backup is very difficult. Each computer should have its own back-up system

14. 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.

16. 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.

17. 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.

18. 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.

19. 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.

20. Network Terms Client Server NOS (Network Operating System )
NIC (Network Interface Card)
Host
Node
Segment
Backbone
Topology
Protocol

21. Network Terms
Packet
Addressing
Transmission media

22. How Networks Are Used Network services Functions provided by a network
Printer sharing
File sharing
Internet access and Web site delivery
Remote access capabilities
Voice (telephone) and video services
Network management

23. 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

24. 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

25. Communications Services
Mail server
Computer responsible for storage and transfer
Intercept spam
Handle objectionable content
Route messages according to rules
Provide Web-based client for checking
Notify administrators or users if certain events occur
Schedule transmission, retrieval, storage, maintenance
Communicate with mail servers on other networks
Mail server runs specialized mail server software

26. Internet Services Web server Other Internet services
Computer installed with appropriate software to supply Web pages to many different clients upon demand
Other Internet services
File transfer capabilities
Internet addressing schemes
Security filters
Means for directly logging on to other Internet computers

27. Becoming a Networking Professional
Job market
Many job postings for computer professionals
Expertise levels required vary
To prepare for entering job market:
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

28. 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

29. 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
Network management
Wireless network design
Configuration of routers and switches
Centralized data storage and management

30. Developing Your “Soft Skills”
Not easily measurable
Important to networking projects
Examples of soft skills
Customer relations
Oral and written communications
Dependability
Teamwork
Leadership abilities

31. 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

32. Pursuing Certification (cont’d.)
Benefits
Better salary
Greater opportunities
Professional respect
Access to better support