Showing posts with label IT/Networking. Show all posts
Showing posts with label IT/Networking. Show all posts

Monday, 3 June 2013

What is Firewall?How its help in network security?


Firewall is a device or a server which helps to protect our network nodes from unauthorised user's.

In simple words,

Firewall is a technique which is used to protect our private network from a public network i.e. Internet.



It is generally divided into 2 parts:-

  • Network firewall:-This firewall is used to check source and destination address of the network.
  • Application firewall:-It is also  used to check source and destination address of the network after network firewall.
Some attributes which are used by network firewall are service control,direction control,behaviour control and user control.Now I discuss some different-2 types of firewall.

Firewall is generally divided into 5 parts that are:-

1)Packet Filtering Router:-It is used to validates the source address of data and allows only authorised user's.

Some information used by Packet Filtering Router are:-

  • Source IP Address.
  • Destination IP Address.
  • Protocols etc.
Advantages and disadvantages of Packet Filtering Router:-

  1. It provide good security.
  2. It is cheap technique as compared to other types of firewall.
  3. It is very complex.
  4. Difficult to manage.
2)Stateful Inspection Firewall or Stateful Packet Inspection Firewall(SPI):-This firewall is use to protect our network from unauthorised user's.It is also provide Synchronisation,Acknowledgement etc.

3)Circuit Level Gateway:-It is used to validates the data packets  from a malicious code.It does not contain any specific proxy server.

4,5)Application Gateway and Guard Firewall:-

Application gateway firewall is also called as proxy server or proxy gateway.It is used to controls most of the protocols like http,ftp,mail protocol etc. from network.It provide good security as compared to SPI but it is very complex.

Guard firewall is the most complex firewall of all time.It is used to audit different-2 activities.

If you have any query then leave your comments and don't forgot to follow me on Google+,Facebook,Twitter.

Wednesday, 22 May 2013

What is Router?


Router is a networking device that send group of messages(packets) to different-2 networks(It will send packets only on those networks which have same protocols).Example Internet or Intranet.

In simple words,
Router is a device which connect two or more networks.
Router chooses the shortest route for data communication.It is used to determine the next network point in which we sends packets.Routing feature is also used in OSI model in network layer.

Type of router:-

1)Wired Router:-Those routers which uses wired medium for data communication.
2)Wireless Router:-Those routers which uses wireless medium for data communication.



Routing methods:-Routing method are of two types-

1)Static routing:-It conclude that how packet will send or received from one network to another.

2)Dynamic routing:-It is much advance than static routing.


If you have any query then leave your comments and don't forgot to follow me on Google+,Facebook,Twitter.

Sunday, 12 May 2013

What is Open System Interconnection Model(OSI Model) and its 7 layers?


OSI stands for Open System Interconnection as I mention in the title of the post.This model is develop by ISO company in 1978.This model allow communication between multiple networks.This model tells how data is travel  from one node to another node in a network.This model represent different-2 layers/levels that tells how our data are transfer from one computer to another.This model overcomes all the limitations of TCP/IP model.
TCP/IP contains only 4 layers i.e. Application layer,transport layer,Internet layer and host to network layer but OSI model contains 7 layers i.e. application layer,presentation layer,session layer,transport layer,network layer,data link layer and physical layer.

In OSI model transmission is done from application to physical layer and receiving is done from physical to application layer.Now I draw the diagram of OSI model that tells how data flow from one layer to other on the basis of transmission as well as receiving.


On the basis of transmission 



On the basis of receiving 


Different-2 layers of Open System Interconnection Model with functions:-

1)Application Layer:-Application layer is the seventh layer of OSI model.It contains applications,protocols etc.Applications like file transfer,email and protocols like FTP,HTTP etc.It is also called as data unit.

2)Presentation Layer:-Presentation layer is the sixth layer of OSI model.This layer is used for encryption of data and this layer is also used for compressing of data for fast transmission.It is also called as syntax layer.

3)Session Layer:-Session layer is the fifth layer of OSI model.This layer is used to manage the dialogue session between the application of data.Session layer also uses different-2 duplex method like simple duplex,half duplex and full duplex.

4)Transport Layer:-Transport layer is the fourth layer of OSI model.This layer is used for transfer data between network.This layer used two protocols namely TCP(Transmission Control Protocol) and UDP(User Data gram Protocol).TCP is the connection oriented protocol as well as it provide more reliable connection as compared to UDP.UDP is connection less protocol and it only receive or transmit data but not manage it as like TCP.It is also called as segment unit.

5)Network Layer:-Network layer is the third layer of OSI model.Network layer uses switches,routers.This layer is also called as packet unit.It represent how packets(group of data) are travels from one node to another.

6)Data Link Layer:-Data link layer is the second layer of OSI model.Those packets which are send from network layer are decode and encode in this layer.Data link layer is also called as frame unit.It has two sub layers i.e. MAC(Media Access Control) and LLC(Logic Link Control).

7)Physical Layer:-Physical layer is the first layer of OSI model.This layer receive data in the form of bit stream(0 or 1).It is also responsible for physical devices like Ethernet,cables,HUB etc.This layer is also called as bit unit.


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Friday, 10 May 2013

Computer Architecture:What is Data Bus?


Data Bus is the bus which carries data and transfer machine instructions(which are given by us)from one place to another,but don't be confused with Address bus(Address bus carries the address not data but it carries the information of data).

Accumulator Data(AC):-AC is also called as Processor Register.The main purpose of AC is to store and accumulate data.


Status Register:-Status register is also called as flag register.Its generally in 1 bit.Some important consideration of flag register are carry,zero,sign,parity.


Program Counter Register(PC):-The main purpose of Program counter register is to execute instruction.


Instruction Register(IR):-The main purpose of Instruction register is to execute and store machine instruction.


Address Register(AR):-The main aim of Address register is to holds the memory address.


Temporary Register(TR):-The purpose of this register is to holds the data temporarily.


Input Register(INPR):-INPR is used to hold the incoming data which are coming from input devices like keyboard etc.


Output Register(OUTR):-OUTR is used to hold the output data.


Data Register:-It is called as DR.It is used to holds the data.  


Now I draw the flow chart/diagram of data bus and its bits table.





Register Number of bits
DR 16
IR 16
AR 12
TR 16
AC 16
PC 12l
INPR 8
OUTR 8


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What is computer Network?Full Article on computer networking


Networking term means when group of devices are connected to each other.So in computer network,interconnected computers are sharing resources.Resources like text,images,video,audio
,files,documents etc.In computer networking not only computer are connected but I/O devices,terminals are also connected and perform data communication.



What are the elements/components of data communication?


1)Message(content of data).

2)Sender(Devices that send data).
3)Receiver(Devices that receive data).
4)Medium(like wired,wireless etc.).
5)Protocol(set up rule of network).

Need/use/Objective/Advantages of Computer Network:-


1)It provide better communication between hardware and software.


2)Network provide sharing of resources.


3)Many times,error free transmissions are take place.


4)It provide good speed for transmission.


5)Networking is very cost effective.


6)Networking is very flexible. 


7)Video conferencing is also possible.


8)It provide good security.


Disadvantages of computer network:-


1)Sometimes,it may be costly.


2)Required lots of effort on installation.


Type of Computer Network:-


1)LAN:-LAN stands for Local Area Network.It is also called as Limited Area Network(But don't write this full form on your final examination).IN LAN,group of computer are connected to each other with in a building,office,school,home etc.


For more help in LAN than please visits Computer LAN(Full link).


2)MAN:-MAN stands for Metropolitan Area Network.In MAN,group of computer are connected to each other with in a whole city.


For more help in MAN than please visits Computer MAN(Full link).


3)WAN:-WAN stands for Wide Area Network.In WAN,group of computer are connected to each other with in a broad geographical area.


For more help in WAN than please visits Computer WAN(Full link).


4)VPN:VPN stands for Virtual Private Network.In Virtual Private Network,group of computer are virtually connected to each other in a private network.


Type of Computer network on the basis of Architecture/Network Models:-

1)Peer to Peer Networking:-In Peer to Peer Networking,group of computer are connected to each other in a network.In this type of networking their is no fix client and server.So it provide less security example cybercafe.

2)Client Server Architecture:-In Client Server Architecture,group of computer are connected to each other in a network.In this type of networking their is fix server and client(Every time server full fill the demand of client node).

What is Topology?

Topology is the physical layout of network.It may be in the shape of ring,star,bus etc.


Computer Network devices:-

Some important networking devices are HUB,switch,modem,router,bridge,gateway etc.These devices are used in transmission of data. 

Transmission Media:-

Transmission Media are used to transfer data from one computer to another computer.

It may be of 2 type:-

Guided Media(Twisted Pair Cable,Co-axial cable and Fibre Optic Cable).

2)Unguided Media(Blue tooth,Infrared,satellite etc.).



That's all about tutorials of basic computer Networking and its applications,if you have any query then leave your comments and don't forgot to follow me on Google+,Facebook,Twitter.

What is Network Topology?


Topology(LAN topology) is said to be the physical layout of the network(shape of the network).It specified how computer/nodes are connected to each other.It also represent the connection of nodes in a network.

Types of topology:-

1)Star Topology:-Star topology consist one central devices(HUB or Switch) which manage the whole data.




Advantages of Star topology:-

1)Easy to extend.

2)Easy to implement.

3)It is reliable.

4)Follow client Server architecture.

5)Transmission speed is very fast.

6)Installation is easy.

Disadvantages of Star topology:-

1)Use so many cables.

2)It is costly.

3)If central device is fail than whole system is down.

2)Ring Topology:-Ring topology are those topology whose physical layout is like a ring.It generally used coaxial cable.




Advantages of Ring topology:-

1)All nodes are equal.

2)Transmission speed is good.

3)Network is more readable.


Disadvantages of Ring topology:-

1)If one cable is loose than whole network is down.

2)If one node is not working than whole network is down.

3)It is expensive too.

3)Tree Topology:-It follow the concept of tree.It is also called as extended star topology.

4)Bus Topology:-Bus topology are those topology whose physical layout is like a linear bus.It is also called as linear topology.




Advantages of Bus topology:-


1)Easy to extend.

2)It is not expensive.

3)Follow client Server architecture.

Disadvantages of Bus topology:-

1)Required more cables.

2)Provide low security.

3)Troubleshooting problem.

4)If one cable is loose than whole network is down.

5)Mesh Topology:-It is also called as point to point topology because in this topology all nodes are connected to each other in a point to point network.




If you have any query then leave your comments and don't forgot to follow me on Google+,Facebook,Twitter.

What is transmission media or transmission medium?


Transmission media is also called as communication medium or channel.Transmission media play a very important role in computer network.In computer networking it is used to transfer resources(like data /information) from one place to another.

Transmission media are of two types:-

1)Guided Media:-Guided media is also called as physical media or wired media.In guided media one network is connected to another network using a set of wires.

Guided media are of 3 types:-

a)Twisted Pair Cable:-Twisted Pair Cable is very common in our daily life,even a phone wires is also made up of Twisted Pair Cables.It consist 8 wires and 4 pairs(2 each).Twisted Pair Cable is very cheap technology as compared to Fiber Optic cable and Coaxial cable.




Twisted Pair Cable again divided into two parts:-

->UTP:-UTP stands for Unshielded Twisted Pair cable.It is effected by EMI(Electro Magnetic Interference).

->STP:-STP stands for shielded Twisted Pair cable.It is not effected by EMI(Electro Magnetic Interference).

b)Coaxial Cable:-Coaxial Cable is made up of copper wire and it provide better shielding and carry more data as compared to Twisted Pair Cable.




Coaxial Cable again divided into two parts:-

->Thin cable:-Only one signal transmit at a time.

->Thick cable:-More than one signal transmit at a time.

c)Optical Fiber Cable:-It provide better and fast communication as compared to Twisted pair cable and coaxial cable.It transfer data at very high speed through light signal.




Optical Fiber Cable again divided into two parts:-

->Single mode Optical Fiber Cable:-One light signal transmit at a time.

->Multi mode Optical Fiber Cable:-More than one light signal transmit at a time.

2)Unguided Media:-Also called as wireless media.Some common example of unguided media are blue-tooth,infrared,satellite etc.


If you have any query then leave your comments and don't forgot to follow me on Google+,Facebook,Twitter.

Thursday, 9 May 2013

What is Local Area Network(LAN)?


You may also like:-What is Wide Area Network(WAN)?

What is Metropolitan Area Network(MAN)?

LAN stands for Local Area Network.It is also called as Limited Area Network.In LAN,group of computer are connected to each other with in a building,office,school,home etc.The range of LAN is very small i.e. 0 to 5 Km.Some component of LAN are nodes,server,NIC(Network Interface Card) etc.LAN basically used only twisted pair cable and common example of LAN is Ethernet.

Diagram of Local Area Network:-




Advantages/Disadvantages/Needs/Characteristics of LAN:-

1)Using LAN,we can access so many devices like Printer,plotter etc.

2)LAN provides great security.

3)LAN is reliable.

4)Easy to manage.

5)Rate of error is very low.

6)Easily expandable.

7)We can transfer our resources very easily.

8)Sharing of resources are of very high speed.

9)Easy to setup.

10)Installation is easy as compared to MAN and WAN.

11)It is very cost effective.

12)Limited number of computer are connected.

13)It connected in a small geographical area.

14)It can be wired or wireless.


If you have any query then leave your comments and don't forgot to follow me on Google+,Facebook,Twitter.

What is Wide Area Network(WAN)?


You may also like:-What is Local Area Network(LAN)?

What is Metropolitan Area Network(MAN)?


WAN stands for Wide Area Network.In WAN,group of computer are connected to each other with in a broad geographical area.


WAN is formed from the combination of two or more MAN.It connected different-2 cities,states or even countries.

Diagram of Wide Area Network:-






WAN  are of 2 types:-


1)Public WAN:-Public Wide Area Network are those network in which the data and information(resources) are access and shared publicly example Internet.


2)Private WAN:-Private Wide Area Network are those network in which the data and information(resources) are access and shared privately example ARPANET.


Advantages/Disadvantages/Needs/Characteristics of WAN:-


1)It covered very large geographical area.


2)Large number of nodes are connected.


3)It may be used in guided(wired) or unguided(wireless) medium.


4)Transmission speed is not such good as LAN.


5)Resources are shared very easily.


6)Error rate is higher as compared to LAN.


7)Easily expandable.




That's all about Wide Area Networking and its components,If you have any query then leave your comments and don't forgot to follow me on Google+,Facebook,Twitter.

What is Metropolitan Area Network(MAN)?


You may also like:-What is Local Area Network(LAN)?

What is Wide Area Network(WAN)?


MAN stands for Metropolitan Area Network.In MAN,group of computer are connected to each other with in a whole city using some network devices like HUB,repeater etc.(we need such devices because in MAN,signal becomes week due to large geographical area so these devices are boost up the signal).It range from 0-100 Km.

Diagram/Image of Metropolitan Area Network:-




Advantages/Disadvantages/Needs/Characteristics/features of MAN:-


1)It covered large geographical area.


2)It is made up the combination of two or more than two LAN.


3)It mainly used Fibre optic cable.


4)It transmission is very fast.


5)It generally covered a city or a town.


6)It support voice communication.


7)It may be used in guided(wired) or unguided(wireless) medium.




If you have any query then leave your comments and don't forgot to follow me on Google+,Facebook,Twitter.

Wednesday, 8 May 2013

What is application software?


You may also like:-What is System Software?

Application Software are those software which are used for specific purposes example MS Word,spreadsheet etc.

This type of software required more work from user's end.

Now I discuss some example/types/lists of application software in brief:-

1)Microsoft Office Word:-Also called as MS word,it comes under a package of MS office.It helps you to create professional looking documents.It contains reviews,font,page layouts,mailing etc.




2)Microsoft Office Excel:-Also called as MS Excel.It is the power full tool of manage your data with ease.It contains cell,column,rows etc.




3)Microsoft Office PowerPoint:-Also called as MS PowerPoint.It is an another important application software which is used for specific purpose.It is used for creating presentations.It contains ribbons,tabs etc.




4)Microsoft Office Access:-Also called as MS Access.It s used to make process of creating database so easy.




5)Paint(Drawing):-This application software is used to make figures,chart,diagram etc.






That's all about computer/PC application software and categories,if you have any query then leave your comments and don't forgot to follow me on Google+,Facebook,Twitter.

What is system software?


You may also like:-What is Application Software?

System software are those software which are used to coordinate with all the operations of the connected device of the computer system.System software manage computer system and also controlled it.

System software control all major operation of computer system(PC) in which some are:-

1)It control all hardware devices including input  devices,output devices etc.

2)It control all software.

3)It control memory management. 

4)It control process management.

5)It can manage all the files and documents.

6)It is also used in I/O management.

7)It is also used to maintain  jobs on the basis of priorities. 

Type of system software:-

1)Programming language software(First generation ,second generation,third generation,fourth generation,Oops.

2)Operating system(like UNIX,windows,Linux etc.).

3)Utility programs(like addition,subtraction,sorting etc.).

4)Subroutines(Repeated task).

Different-2 environment of system software or Examples:-

1)Single user environment(DOS,Windows)

2)Multi -user environment(Linux,Unix).



If you have any query then leave your comments and don't forgot to follow me on Google+,Facebook,Twitter.

What is computer software?Explain its different types


Software are the set of programs/packages which we can not touch and feel as like hardware(It is device which we can touch and feel).Software provide better communication between computer/PC and user.


Software is the combination of instructions to perform the specific task.

Relation between Software,hardware and user(Diagram):-





Types of Software:- 

1)System Software:-System software are those software which we can used to control the system and also used for run applications.

Example:-DOS,Unix etc.

For more help on System software than visits System software(full link).

2)Application Software:-Application software are those software which are designed to perform a specific task.

Example tally,payroll etc.

For more help on Application Software than visits Application Software(full link).

3)Utility Software:-Utility software are those software which are used by everyone.

Example:-MS Office.

4)Presentation Software:-Presentation Software are those software which are use to create/make computer presentations.

Example PowerPoint.

5)Language Software:-Language software are those software which are used to developed languages code.

Example:-c,c++,HTML5 etc.

If you have any query then leave your comments and don't forgot to follow me on Google+,Facebook,Twitter.