Basic Concepts of Computer networking, Study notes of Computer Networks

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Basic Concepts of

Computer Networking

Nitin Sharma Technical Assistant

1. Introduction

2. Advantages & Disadvantages of Computer Network

3. Basic Terminology Used in Computer Network

4. Types of Network

5. Classification of Network Architecture

6. Network Protocols

7. Network Topology

8. NIC (Network Interface Card)

9. Transmission Media/Cables

10. Hub vs Switch vs Router

11. Server and Its Types

12. Firewall and its Types

13. References PUSHPA GUJRAL SCIENCE CITY, KAPURTHALA

CONCEPT

ADVANTAGES OF COMPUTER NETWORKS

FILE SHARING : A person sitting at one workstation of a network can easily see the files present on the other workstation, provided he is authorized to do so. RESOURCE SHARING : All computers in a office can be interconnected using a network and one printer can efficiently provide the services to all four members. INCREASE STORAGE CAPACIY : A standalone computer might fall short of storage memory, but when many computers are on a network, memory of different computers can be used in such case. INCREASE COST EFFICIENCY : Computer networks resolve this issue as the software can be stored or installed on a system or a server and can be used by the different workstations

DISADVANTAGES OF COMPUTER NETWORKS

SECURITY ISSUES : A computer hacker can get unauthorized access by using different tools. In case of big organizations, various network security softwares are used to prevent the theft of any confidential and classified data. RAPID SPREAD OF COMPUTER VIRUSES : If any computer system in a network gets affected by computer virus, there is a possible threat of other systems getting affected too. EXPENSIVE SETUP : Costly devices like routers, switches, hubs, etc., can add up to the bills of a person trying to install a computer network. DEPENNDECY ON MAIN SERVER : In case the main File Server of a computer network breaks down, the system becomes useless. In case of big networks, the File Server should be a powerful computer, which often makes it expensive.

BASIC TERMINOLOGY USED IN COMPUTER NETWORK

Hard-wired : This means that all the workstations in the office plug into a network outlet using physical cabling to transport data to and from the server. Network Interface : is a software interface to networking hardware. For instance, if you have two network cards in your computer, you can control and configure each network interface associated with them individually. Connection : refers to pieces of related information that are transfered through a network. Gateway : A gateway is a device that routes traffic between networks. For example, at home, your router is your gateway. It provides a “gateway” between your LAN and WAN. Bandwidth : Bandwidth refers to a capacity of line means how much data transfer through a cable or line.

Based on the size and the coverage area, networks are categorized into

the following types:

Personal Area Networks (PAN)

Local Area Networks (LAN)

Metropolitan Area Networks (MAN)

Wide Area Networks (WAN)

A local area network (LAN) is a network that connects computers and devices in a limited geographical area such as a home, school, office building, or closely positioned group of buildings. Each computer or device on the network is a node. Wired LANs are most likely based on Ethernet technology.

It is relatively larger than LAN and extends across a city or a

metropolitan.

It is created by connecting two or more LANs located at different

locations in a city.

On a network built using the client-server architecture, the devices

communicate to other devices through a central computer referred to as a

server.

The server is a terminal with high processing power, which provides

services for the other computers on the network.

On a network built using the peer-to-peer architecture, no specific distinction exists between a client and a server. Any node can provide a service as well as send a request for a service from another node on the network.

Network protocols are formal standards and policies made up of rules,

procedures and formats that defines communication between two or more

devices over a network. Network protocols conducts the action, policies, and

affairs of the end-to-end process of timely, secured and managed data or network

communication.

The Main different types of Network Protocols are:  Internet Protocol  TCP  HTTP  FTP  TelNet  SMTP  POP  SNMP  IMAP  HTTPS or SSL

NETWORKS PROTOCOLS

INTERNET PROTOCOL (IP) : The Internet Protocol is the principal protocol in the Internet protocol suite for relaying data across networks. Its routing function essentially establishes the internet. Historically it was the connectionless datagram service in the original Transmission Control Program; the other being the connection oriented protocol(TCP). Therefore, the Internet protocol suite is referred as TCP/IP. TRANSMISSION CONTROL PROTOCOL (TCP) : TCP provides reliable delivery of a stream of octets over an IP network. Ordering and error-checking are main characteristics of the TCP. All major Internet applications such as World Wide Web, email and file transfer rely on TCP. Hypertext Transfer Protocol (HTTP) : The HTTP is the foundation of data communication for the World Wide Web. The hypertext is structured text that uses hyperlinks between nodes containing texts. The HTTP is the application protocol for distributed and collaborative hypermedia information system. Its Default Port is 80 File Transfer Protocol (FTP) : The FTP is the most common protocol used in the file transferring in the Internet and within private networks. The default port of FTP is 20 / 21.

NETWORKS PROTOCOLS … Contd

Simple Network Management Protocol (SNMP) :The Simple Network Management Protocol is used to manage networks. It has abilities to monitor, configure and control network devices. SNMP traps can also be configured on network devices to notify a central server when specific action are occurring. The default port of SNMP is 161 / 162. Hypertext Transfer Protocol Secure (HTTPS) : It is also Known as Secure socket Link. HTTPS is used with HTTP to provide same services, but with a secured connection which is provided by SSL or TLS. The default port of HTTPS is 443. Internet Control Message Protocol (ICMP) : This protocol is used by network devices, including Router to send error messages and operational information indicating success and failure when communicating with another IP address.

The pattern of interconnection of nodes in a network is called the Topology.

This layout also determines the manner in which information is exchanged

within the network.

The different types of network topologies that can be used to set up a network

are:

 Bus Topology  Ring Topology  Star Topology  Mesh Topology  Tree Topology  Hybrid Topology