Computer Awareness for Bank Exams like IBPS PO, SO, Clerical, SBI, RBI and others.

Computer Networks – Basic concepts for Bank Exams:

1. What is a Computer Network?
   • A Computer Network is a collection of Computers and Devices which are connected via communicating devices and transmission media to enable transmission of meaningful data and information between them.
2. What are the various modes of Data Transmission?
   • Simplex mode– In which data can flow only in one direction.
   • Half Duplex mode – In which data can flow in both direction but only in one at a time.
   • Full Duplex mode – In which data can transmit in both direction at the same time.
3. What do you mean by Network Topology?
   • Network Topology refers to the way various nodes of the network are connected to each other in a network. It determines the data path available for transmission of data.
4. What are the important Network Topologies?
   • BUS, RING, STAR, MESH
5. Describe various types of Computer Networks on geographical basis?
   • 3 types – LAN, MAN, WAN.
6. What is LAN?
   • LAN stands for Local Area Network. It is a network that connects computers in a limited geographical area like home, a classroom, a building  etc.
7. What is MAN?
   • MAN stands for Metropolitan Area Network.  It is a network that connects computers or many LANs in a metropolitan area such as a city or a town. It covers larger area than a LAN but smaller area than a WAN.
8. What is WAN?
   • WAN stands for Wide Area Network. It is a network that covers a much wider area such as a country or a continent or whole world. e.g INTERNET
9. What do you mean by Network Architecture?
   • Network Architecture means the overall design of a Computer Network. Also known as Network Model. Basically of two types – Client-Server Model and Peer to Peer Model.
10. What is a Client-Server Model?
    • In a Client Server Model, one computer acts as a SERVER that provides with the services and resources. And all other computers act as clients that request the server to provide the services and resources.
11. What is Peer to Peer Model?
    • In this Network Model, there is no server. Each computer has an equal capability to access all the services and resources available on the network.
12. What is the importance of using a Computer Network?
    • Sharing of Files, Data, Information.
    • Sharing of Resources like Printers, Scanners etc.
    • Sharing of Internet Connection.
    • Better communication with network services like E-mail, Webchat etc.
13. What is an IP Address?
    • Each device when connected to the network is given an address to communicate. This Address is called as an IP Address.
14. What is a Network Adapter or NIC?
    • It is a piece of hardware that physically connects the device to the network.
15. What is a HUB?
    • A Hub is a physical device that acts as a central connecting point and joins paths in a STAR network topology.
16. What is a Repeater?
    • Repeater is a device that is used to combat attenuation. It increases the strength of the degraded signal and passes it on.
17. What is a Bridge?
    • It is another device to connect network segments. It works at the Data Link Layer.
18. What is a Router?
    • It is a device to connect two or more network segments. It works at the Network layer.
19. What is a Gateway?
    • A Gateway is usually a dedicated computer running a Gateway software that enables connection between two dissimilar networks.
20. What is a BUS Topology. What are its advantages and Disadvantages?
    • In BUS Topology, all nodes share a single transmission medium. A node just appends destination address to the message and checks whether communication line is free.
    • Advantages : It helps in reducing the number of physical lines. Failure of a node does not affect communication among other nodes in the network. Addition of a new node to the network is easy
    • Disadvantages : If the shared communication line fails, entire network fails.
21. What is a RING Topology. What are its advantages and Disadvantages?
    • Each node has is connected to its adjacent nodes with which it can communicates directly, but there is no master node for controlling other nodes. Node receives data from one of its two adjacent nodes.
    • Advantages : There is no central node for making routing decision.It is more reliable than a star network because communication is not dependent on a single central node. If a link between any two nodes fails, or if one of the nodes fails, alternate routing is possible.
    • Disadvantages : Communication delay is directly proportional to number of nodes in the network. Addition of new node in a network increase communication delays. It requires more complicated controls software than star topology.
22. What is a STAR Topology. What are its advantages and Disadvantages?
    • Multiple Nodes are connected to a host node. Nodes in the network are linked to each other through the central host node and can communicate only via the central node.
    • Advantages : Transmission delays between two nodes do not increase by adding new nodes to network, because any two nodes are connected via two links only. If any node other than the host node fails, remaining nodes are unaffected.
    • Disadvantages :The system crucially depends on the host node. If it fails, entire network fails.
23. What is a MESH Topology. What are its advantages and Disadvantages?
    • Separate physical link for connecting each node to any other node. Each node has a direct link, called point-to-point link, with all other nodes in the network.
    • Advantages : It is very reliable as any link failure will affect only direct communication between nodes connected by that link.  Communication is very fast in this type.
    • Disadvantages : It is the most expensive network from the point of view of link cost.
24. Define  TCP and IP?
    • TCP – Transmission Control Protocol. TCP  helps to establish a connection and exchange streams of data. TCP guarantees delivery of data and also guarantees that packets will be delivered in the same order in which they were sent.
    • IP – Internet Protocol. It  has the task of delivering packets from the source host to the destination host solely based on the IP addresses in the packet headers.
25. What is DNS?
    • It stands for Domain Name Service/System. It provides a means to attach a name to an IP Address making it easier for us to request resources. e.g Google.com
26. What is VoIP?
    • VoIP stands for Voice Over Internet Protocol. It is a service which uses an Internet connection for making voice calls, video calls, tele-conferencing etc. e.g. Google Voice, Skype etc.
27. What is VPN?
    • It stands for Virtual Private Network. It is a means of joining two networks with each other when they are not physically together.
28. What is a Server?
    • A computer or an application that is capable of accepting requests from the clients and giving responses accordingly.
29. What is a Firewall?
    • A firewall can be defined as a network security system that controls the incoming and outgoing network traffic based on an defined rules. A firewall establishes a barrier between a trusted, secure internal network and another network that is assumed not to be secure.
30. What is DMZ?
    • It stands for De-militarised zone. It is a critical part of the Firewall. It is a network that is neither the part of trusted network nor the untrusted one but connects both of them.
31. What is a Proxy Server?
    • A proxy server is a host which acts on behalf of another computer and has the ability to fetch documents/information on behalf of the client.
32. Port numbers of important protocols?
    • FTP DATA – 20
    • FTP CONTROL – 21
    • SSH Remote Login – 22
    • TELNET – 23
    • SMTP – 25
    • DNS – 53
    • HTTP – 80
    • POP3 – 110
    • HTTPS – 443
33. What is Cloud computing?
    • Cloud computing is  defined as a type of computing that relies on sharing computing resources rather than having local servers or dedicated resources or applications.
34. What is Intranet?
    • An intranet is a computer network that uses IP technology to share information,  or computing services within an organization. It can also be defines  as a  network within an organization.
35. What is Extranet?
    • Extranet is a computer network that allows controlled access from outside to an organization’s intranet to securely share part of business operations or informations.
36. Define Internet?
    • The Internet is a global system of interconnected computer networks that use the standard TCP/IP protocol suite to link many networks and devices worldwide. It can be called as a Network of Networks.
37. Define WWW?
    • WWW stands for World wide web. It can be defined as the  resources and users on the Internet that are using the Hypertext Transfer Protocol (HTTP).
38. What is HTTP?
    • Stands for Hypertext Transfer Protocol. HTTP is the application layer  protocol which is used by the World Wide Web. HTTP defines how the messages are formatted and transmitted, and what actions Web servers and browsers should take against various commands.
39. What is HTML?
    • Stands for HyperText Mark up Language. It defines how the webpages will be formatted and displayed by the browsers.
40. What is FTP?
    • It stands for File Transfer Protocol which is used to transfer computer files from one host to another host over a TCP-based network.
41. What is Cryptography?
    • Cryptography is the method of storing and transmitting data in a particular form so that only those who are intended to read the data can read and understand it. It involves Encryption (i.e. converting the simple text into a cipher text ) and Decryption (i.e. converting the cipher text back into simple text).
42. What is Private-Key Cryptography?
    • Private-Key Cryptography involves Encrypting and Decrypting the data by a single private key which is known only to the sender and receiver of the data. There is a risk of losing the key by either side which can break the whole system.
43. What is Public-Key Cryptography?
    • Public-Key Cryptography involves encrypting the data with a Public key of the receiver which can only be decrypted by the Private-Key of the receiver. It ensures confidentiality and security.
44. What is a Digital Signature?
    • Digital Signature is a technique to validate the authenticity of  a document/text/message sent by the sender. It makes the receiver of the data believe that the message has been sent by the sender and the sender cannot deny sending the message.
45. Why is Network Security required?
    • To save the confidential and sensitive data from the hackers who can exploit the vulnerabilities of a network.
46. What is IP-spoofing?
    • It is a kind of network attack where one host claims to have the IP address of someone else to gain unauthorised access to information or services.
47. What is DOS attack?
    • DOS stands for Denial of Service attacks. It simply means sending the machine more requests than it can handle and eventually letting the machine break down.

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