Introduction to Networks

M. Sabari Ganesh M.Tech.,Sr.Lecturer/ECE

What is Network?• A network is a group of computers and other devices

(such as printers) that are connected by some type of transmission media

• A network can be as small as two computers connected by a cable in a home office or as large as several thousand computers connected across the world via a combination of cable, phone lines, and cellular links.

• Networks might link mainframe computers, printers, plotters, fax machines, and phone systems. They might communicate through copper wires, fiber-optic cable, or radio waves.

Why Use Networks?

• Networks enable multiple users to share devices (for example, printers) and data (such as spreadsheet files), which are collectively known as the network’s resources.

• Sharing devices saves money.• Networks also allow you to manage, or

administer, resources on multiple computers from a central location.

Types of Networks

• Peer to Peer Networks• Client/Server Networks• LAN (Local Area Network)• MAN ( Metropolitan Area Network) • WAN ( Wide Area Network)

Peer to Peer Networks

• It is a simplest form of a network • Every computer can communicate directly

with every other computer.• No computer on a peer-to-peer network has

more authority than another. However, each computer can be configured to share only

some of its resources and prevent access to other resources.

Peer to Peer Networks(Contd)

• Traditional peer-to-peer networks typically consist of two or more general-purpose personal computers, with modest processing capabilities.

• Every computer is capable of sending and receiving information to and from every other computer.

Peer to Peer Networks

Advantages

• They are simple to configure. For this reason, they may be used in environments in which time or technical expertise is scarce.

• They are often less expensive to set up and maintain than other types of networks.

Disadvantages

• Not flexible.• Insecure.• Cannot connect many computers.

Client/Server Networks

• It is a network that uses a server to enable clients to share data, data storage space, and devices.

• It is also used to refer to the design of a network in which clients rely on servers for resource sharing and processing.

• Every computer on a client/server network acts as a client or a server.

Client/Server Networks (contd)

• Clients on a network can still run applications from and save data to their local hard disk. But by connecting to a server, they also have the option of using shared applications, data, and devices.

• Clients on a client/server network do not share their resources directly with each other, but rather use the server as an intermediary.

• Clients and servers communicate through connectivity devices such as switches or routers.

Client/Server Networks (contd)

• To function as a server, a computer must be running an NOS (network operating system)

• Servers have more memory, processing, and storage capacity than clients.

• They may even be equipped with special hardware designed to provide network management functions beyond that provided by the network operating system.

Client/Server Networks

Advantages

• User logon accounts and passwords for anyone on a server-based network can be assigned in one place.

• Access to multiple shared resources (such as data files or printers) can be centrally granted to a single user or groups of users.

• Problems on the network can be monitored, diagnosed, and often fixed from one location.

Advantages (contd)

• Servers are optimized to handle heavy processing loads and dedicated to handling

requests from clients, enabling faster response time.

• Servers can connect more than a handful of computers on a network.

• They are more scalable.

LAN (Local Area Network)

• It is a network of computers and other devices that is confined to a relatively small space, such as one building or even one office.

• Small LANs first became popular in the early 1980s. • Initially LANs consisted of a handful of computers

connected in a peer-to-peer fashion. • Today’s LANs are typically much larger and more

complex client/server networks.

Interconnected LANs

MAN

• A network that is larger than a LAN and connects clients and servers from multiple building is known as a MAN (metropolitan

area network). • It uses different transmission technology and

media than a LAN.

WAN

• A network that connects two or more geographically distinct LANs or MANs is called a WAN (wide area network).

• This network carry data over longer distances than LANs, WANs may use different transmission methods and media than LANs.

• The largest and most varied WAN in the world is the Internet.

WAN

Transmission Media

Terminologies

• TopologyThe physical layout of a computer

network. Networks can be arranged in a ring, bus, or star formation.

The star topology is most commonly used.

Hybrid combinations of these patterns are also possible.

Topology

Terminologies (Contd)

• ProtocolA standard method or format for

communication between networked devices.• Packet

A distinct unit of data exchanged between nodes on a network. Breaking a large stream of data into many packets allows a network to deliver that data more efficiently and reliably.

Terminologies (Contd)

• Addressing The scheme for assigning a unique identifying

number to every node on the network. The type of addressing used depends on the

network’s protocols and network operating system. Each network device must have a unique

address ( MAC address)so that data can be transmitted reliably to and from that device.

Terminologies (Contd)

• NIC (network interface card) The device that enables a workstation to

connect to the network and communicate with other computers.

NICs are manufactured by several different companies and come with a variety of specifications that are tailored to the workstation’s and the network’s requirements.

It is also called as network adapters.

Terminologies (Contd)• Repeaters– It is the simplest type of connectivity devices that

regenerate a digital signal.• Hub is a repeater with more than one output port. It

accepts signals from a transmitting node and repeats those signals to all other connected nodes in a broadcast fashion.

• Bridges are devices that connect two network segments by analyzing incoming frames and making decisions about where to direct them based on each frame’s MAC address.

Bridge

Types of Services

• Printing• File sharing• Internet access• Remote access• Communicating in multiple forms and• Network management

Network Components

Switch

Connecting a Workstation to Switch

Switch on a Small Network

Routers

Routers on a LAN

International Certifications

Certifications

• CompTIA (Computing Technology Industry Association)

• MCITP (Microsoft Certified IT Professional) • CCNA (Cisco Certified Network Associate)• CCIE (Cisco Certified Internetwork Expert)• Network+ (Net+)• A+ certification (CompTIA)

Thank You