Basics Of Networking

Basics of Telecommunicatio

ns and Networking

Lecture Plan Network Architecture

Network standards and open systems

Virtual private network

Network management system

Networking A network is a group of interconnected

systems which share services and interact with each other by means of a shared communication link.

These systems can be located

anywhere. Network is often classified according to its geographical size.

Classification of Network

The most common classifications of networks are:

Local Area Networks (LAN) Wide Area Networks (WAN)

Metropolitan Area Networks (MAN)

Personal Area Networks (PAN)

Local Area NetworksComputer network connecting computers

and other devices in a workgroup,department, building or campus.

Connects BNs and MANs and are usually leased from inter-exchange carriers.

Typically span hundreds or thousands of miles.

Supports data rates of 28.8 Kbps to 2 Gbps.

Wide Area Networks

Wide Area Networks

Metropolitan Area Networks

• Is a telecommunication network that connects users and their computers in a geographical area

• This area is larger than covered by a LAN but smaller than covered by WAN.

• E.g City or college campus

• A network that supports the interconnection of information technology within a range of 33 feet or so.

Personal Area Networks

You may be connected through:

SatelliteDial-upLeased lineRF Link

What is Internet?1. The Internet is “The Network of

Networks”2. Internet is like a phone system which• connects( almost anywhere in the world),

Exchanges information• Acts as Global link between regional

networks• Allows unrestricted access3. Used for• Communication through email, Chatting • News groups, Files transfer• Documents, data (multimedia )sharing

etc

Internet: An Illustration

Internet

MediaFinance

Computers

Real EstateEducation

HealthGovernment

Universities Business

ServerServer

User

ClientClient

Model of Internet SetupModel of Internet Setup

ClientServer

Client

Email client sends message to server Message is stored

on POP server

Later, recipient’s email client retrieves message from server

Email application

Internet

• Publicly accessible network of interconnected computers which communicate via software protocol standards

• Easily accessed (via modem and phone line, ISDN, direct cable landline, satellite)

• Expanding global infrastructure

Intranet• It is an internal corporate network

built using Internet and World Wide Web standards and products.

• It is used by employees to gain access to company information

Extranet• A network based on web

technologies that links selected resources of a company’s intranet with its customers, suppliers, or other business partners.

To summarize Type Users

Need of user id and password

Internet Anyone No

Intranet Employees & Managers Yes

Extranet Business partners Yes

Virtual Private Network

• It is used for secure intranet and extranet access applications.

• A VPN is a secure connection between two points across the Internet.

VPN - Layout

TunnelISP ISP

Firewall(data Encoded)

Firewall(data Encoded)

Sending Computer Receiving Computer

Computer Network topology

• A communications network is two or more computers connected to share data and resources are “networked.”

• The simple idea behind computer networking is to allow users to access more information and give them access to devices not directly attached to their “local” system, such as printers or storage devices.

Computer Networks• Network connections can also be made

using RADIO transmission – Wireless.

• Allows user to stay connected to their home/office network using portable PC or PDA or may be Cell phone.

• Two Technologies that use wireless networking – Bluetooth (for home or small office use) and wireless Ethernet.

Local Area Networks- 3 basic topologies

•These are either the logical or physical way the computers are connected.

•Each connection on the network is known as a node.

•These topologies are:• Star• Bus• Ring•Mesh [ Partially connected, Fully connected ]•Tree

A Star topology connects all the nodes directly to the server or to a connecting device such as a hub.

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All nodes on a Bus topology are connected to a central line or backbone.

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Nodes on a Ring topology are connected in a closed loop. This means that each node has two connections, one in and another out. Using this type of topology the data must travel through all the nodes.

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