Network / Computer Networks

The collection of interconnected computers is called a computer network.

 

A computer network is a logical or physical interconnection between two or more computers such that they could communicate with each other.

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Data Communication

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Two computers are said to be interconnected if they are capable of sharing and exchanging information. The process of transferring data between computers is known as data communication.

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Need of Computer Networks

 

• Resource Sharing - Resource Sharing means to make all programs, data and peripherals available to anyone on the network irrespective of the physical location of the resources and the user.

• Reliability - Reliability means to keep the copy of a file on two or more different machines, so if one of them is unavailable (due to some hardware crash or any other) them its other copy can be used.

• Cost Factor - Cost factor means it greatly reduces the cost since the resources can be shared.

• Communication Medium - Communication Medium means one can send messages and whatever the changes at one end are done can be immediately noticed at another.

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Application of Networks

• Sharing of data, services and resources

• Access to remote database

• Communication facilities

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Advantages of Computer Network

• The Computers on the Network can share hardware devices like printer, scanner, etc.

• Data and software can be shared within the computer on the network.

• Files can by transferred from one computer to another computer.

• Computers in the network can communicate with each other.

 

Disadvantages of Computer Network

• Data and information may be stolen by computer hackers.

• If any computer in the network gets affected by the virus, there is a high chance of spreading a computer virus.

• Computers on the network have to depend on the server

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Terminology of Networks

 

Nodes /  Workstations - The term nodes refer to the computers that are attached to a network and are seeking to share the resources.

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Server -  A computer that facilitates the sharing of data, software and hardware resources on the network , is called Server. A network can have more than one server also. Each server has a unique name on the network and all users of network identify the server by its unique name.

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Types of Server

 

There are two types of server:-

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(a) Non-dedicated  -  

A workstation, that can work as Server also, called Non-dedicated server, It can facilitate the resource-sharing. It is slower and require less memory. Networks with non-dedicated server is known as PEER-TO-PEER networks.

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(b) Dedicated server -

A Computer, specially reserved for the Server purpose, called Dedicated Server. Its only job is to help workstations access data, software and hardware resources. Networks with Dedicated server is known as MASTER-SLAVE networks. 

File Server – storing files, controlling access and amount of storage for users.

Printer Server – takes care of the printing requirement.

Modem Server – helps a group of network users use a modem to transmit long distance messages.

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Network Interface Unit (NIU) / MAC Address

A network interface unit is a device (network card) / interpreter that helps in establishing the communication between the server and the client.  

Network interface-unit, has a unique number to identify the node/workstation, called Node address. The NIC manufacturer assign a unique physical address to each NIC card, known as Media Access Control address (MAC Address). MAC address is a 6-bytes address with each byte separated by colon(:). It has two parts - Manufacturer ID (First 3 bytes) and Card No(Next 3 bytes).

  Example :=>      AB  :  8C  :  32   :  89  :   B4  :  6E

               manufacturer id       card-no

MAC address is unique for each network card. To check your computer MAC address , do the following : -

Open cmd (Command Prompt),

type ipconfig or ipconfig/all,  and press enter key.

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IP Address

Set of rules are called Protocols. TCP/IP is the most common networking protocol, which follows by Internet also.

Every computer on TCP/IP network has a unique identifying number, called an IP address. IP addresses are needed so that different networks can communicate with each other. Each IP address is actually a series containing four numbers separated by dots or periods e.g. 192.168.100.10 . IP addresses are normally written in dotted decimal form

IPv4 address - older version of IP address is 32-bit long.

IPv6 address – newer version of IP address is 128-bit long. 

  Example 

2001 : 0db8 : 85a3 : 0000 : 0000 : 8a2e : 0370 :7334  (each group is 16 bits long)
 

To Download PPT - Click Here Introduction to Network  

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