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Transcript
Computer Networks Viva Questions 1. The application layer is ___________ of the OSI model. Layer 7 2. What is the use of HTTP? Hypertext Transfer Protocol (HTTP) is used to transfer files that make up the web pages of the World Wide Web. . 3. Which is the most popular network service? E-mail, the most popular network service. 4. FTP requires ___________ connection(s) between client and server to successfully transfer files. To successfully transfer files, FTP requires two connections between the client and the server: one for commands and replies and another for the actual file transfer. 5. What is the use of DHCP? The Dynamic Host Configuration Protocol (DHCP) enables clients on a network to obtain IP addresses and other information from a DHCP server. 6. Which connection is made using Telnet? A connection using Telnet is called a VTY session, or connection. 7. Is eBay a peer-to-peer or client/server application? eBay is a client/server application. eBay is implemented as a web server that responds to web client (browser) requests using HTTP. 8. In the client/server model, the device requesting the service is referred to as the ___________. Client. 9. DHCP allows the automation of what? Assignment of IP addresses, subnet masks, and default gateway. The protocol automates the assignment of IP addresses, subnet masks, gateway, and other IP networking parameters. 10. What does FTP stand for, and what is it used for? FTP stands for File Transfer Protocol. It is used to move files on the network. FTP was developed to allow file transfers between a client and a server. 11. Which form of communication is a real-time, text-based communication type used between two or more people who use mostly text to communicate? Instant messaging is both text based and real time. 12. Rules that govern the process of network communication are called ______________. Protocols 13. Copper cables and fiber-optic cables are two types of network ___________________. Media 14. Symbols that graphically represent network devices and media are called ___________. Icons 15. Give reasons why circuit-switched, connection-oriented technologies rejected when the Internet was being developed? Early circuit-switched networks did not automatically establish alternative circuits in the event of circuit failure. Circuit-switched technologies required that an open circuit between network endpoints be established even if data was not being actively transferred between locations. The establishment of simultaneous open circuits for fault tolerance is costly. 16. Give reasons why a packet-switched, connectionless data communications technology used when developing the Internet? It can rapidly adapt to the loss of data transmission facilities. It efficiently utilizes the network infrastructure to transfer data. Data packets can travel multiple paths through the network simultaneously. 17. A _____________ is a device that helps direct messages between networks. Router 18. Which OSI layer is associated with IP addressing? IP addressing is a concern of the OSI network layer (Layer 3). 19. The elements of communication include a message source, a message destination, and a ___________________, or medium, to transport the message. Channel 20. Which type of addressing is found at the OSI Layer 2? A MAC address is the physical address burned on to the OSI Layer 2 network interface card. 21. Which term describes a specific set of rules that determine the formatting of messages and the process of encapsulation used to forward data? A protocol describes a specific set of rules for communication, including message formatting and encapsulation. 22. A limited-use protocol owned by a company is considered to be _________________________. Proprietary 23. Which protocol is associated with Layer 4 of the OSI model? TCP 24. The device that connects a device to the media is called a/an _________________________. NIC, or network interface card 25. A device that moves data between networks is a _______________. Router 26. What is the process for interweaving multiple data streams onto one shared communication channel or network medium? Multiplexing 27. IP addressing is associated with which layer? IP addressing is an OSI Layer 3 function. 28. What is the correct “top down” order of the OSI model? The correct order is application, presentation, session, transport, network, data link, physical. 29. Which layer of the OSI model is concerned with end-to-end message delivery over the network? End-to-end message delivery is the concern of OSI Layer 4, the transport layer. 30. Which port number is used by HTTP? Port 80 is the standard port number used with HTTP 31. Which characteristics are parts of TCP? TCP is a reliable, connection-oriented protocol. 32. What is the purpose of transport layer port numbers? Port numbers allow you to track multiple conversations generated by the same host using the same IP address. 33. In networking terms, what is reliability? Reliability means ensuring that each segment that the source sends arrives at the destination. 34. List three network applications that use TCP. Web browsing, e-mail, file transfer. 35. List three network applications that use UDP. DNS, video streaming, Voice over IP (VoIP). 36. Which protocol provides connectionless network layer services? IP provides connectionless network layer services. . 37. What are three pieces of information about a route that a routing table contains? A routing table contains the next-hop, metric, and destination network address. Routers do not need the source address, last hop, or default gateway to find a path to a network. 38. What is the name of the process of removing the OSI Layer 2 information from an IP packet? Decapsulation. 39. Why is IP “media independent”? IP encapsulates OSI Layer 4 data. IP can carry voice, video, and other types of data, but “media independent” refers to the OSI Layer 1 medium that carries the data across the networks. 40. TCP is a __________ layer protocol. Transport 41. How many bits are in an IPv4 address? There are four octets (8 bits each) in an IPv4 address. 42. Copper and fiber-optic cable are examples of ____________, which is used to carry the communication signal. Physical media 43. What is the purpose of encoding? Encoding represents the data bits by using different voltages, light patterns, or electromagnetic waves as they are placed onto the physical media. 44. What two signaling methods use voltage to encode bits? NRZ (non-return to zero) and Manchester. 45. What best describes the purpose of the physical layer? The chief purpose of the physical layer is to define the functional specifications for links between end systems and the electrical, optical, and radio signals that carry data. 46. What is the most common Unshielded Twisted Pair (UTP) connector type? RJ-45 47. Through what process does UTP cable help to avoid crosstalk? Crosstalk is reduced by the twisting of cables in the UTP (unshielded twisted-pair) cable. UTP has no cladding, shielding, or grounding points. 48. What is the required order of wires in a connector called? Pinout 49. What are the advantages of using fiber-optic cable over copper cable? Immunity to electromagnetic interference Longer maximum cable length Greater bandwidth reception and decoding requirements Antenna design. 50. The physical media most susceptible to security breaches is ____________. Wireless. Because wireless is open to anyone with a wireless receiver, it is more susceptible to security breaches than copper or fiber-optic media. 51. What is the purpose of cladding in fiber-optic cables? Cladding helps prevent light loss. 52. A _______cable is also known as a Cisco cable because it is generally used as a connection to Cisco equipment. Rollover cable 53. What is synchronization? Synchronization between devices allows them to know when frames begin and end. 54. Which command turns on a router interface? Router (config-if)#no shutdown 55. What is the purpose of the IOS enable secret command? To allow a user to enter a password that will be encrypted. 56. Which command will display statistics for all interfaces configured on a router? Router# show interfaces 57. What command will display a list of commands available for viewing the status of the router? Router# show ? 58. An administrator configures a new router and names it Lab1. The administrator needs to set a password that will be required to establish a console session with the router. What command should be issued by the administrator to set the console password to CISCO? Lab1 (config) # line con 0 Lab1 (config-line)# login Lab1 (config-line)# password CISCO 59. What type of cable is used to initially configure a router? A rollover cable connected to the serial port of a computer is used. 60. What do routers use to select best paths for outgoing data packets? Routing tables 61. What is setup mode? Setup mode allows you to configure a router by answering a series of questions posed to you. 62. What is a configuration file? Configuration file contain the Cisco IOS Software commands used to customize the functionality of a cisco device. 63. What are the methods to access CLI? Console Port Auxiliary Port Telnet 64. Explain Privileged Executive Mode? Privileged exec mode is identified by the prompt ending with the # symbol. It is used by the network administrator for the execution of configuration and management commands. 65. Explain the error messages: Invalid input? IOS returns a caret “^” symbol to indicate where the command interpreter cannot decipher the command. 66. How can we take help when configuring? Enter a question mark (?) at any prompt. 67. Which command is used to restore ‘Default router factory name’? Adil# no hostname Router# 68. What are the different modes used in configuring a router? User Executive Mode Privileged Exec Mode Global Configuration Mode 69. Which device forms boundaries between the Broadcast domains? Router 70. Which command turns on a router interface? Router (config-if) # no shutdown 71. What is IOS? Internetworking Operating System. 72. What is the difference between start-up and Running configuration? Start-up configuration is used as the backup configuration and loaded when the device is started while running configuration is used during the current operation of the device. 73. Explain user Executive mode? A mode that is very limited in scope, allowing basically only “viewing” types of IOS commands. 74. Which command is used to move from ‘Privileged Execution Mode’ to ‘User Execution Mode’? Router # disable 75. Ping message is a ………………….. Unicast message 76. ARP message is a …………………… Broadcast message 77. What is the difference between Hub and Switch? Hub is a layer 1 non-buffering device. Switch is a layer 2 buffering device and it makes collision domains. 78. What is the need for Internet? When two devices are connected in a network, ARP packets traverse between the two computers. ARP packets are broadcast packets; they will traverse to each computer in a network, which consumes a sufficient bandwidth. In order to save this bandwidth, routers are used. Routers not only divide a large single network into smaller networks but also stop broadcast messages. ARP message cannot pass through router so it saves a lot of bandwidth. (Note: This is the most valid reason that supports this argument however not the only reason of making internet) 79. What is the purpose of login command? Login command prevents Telnet access to the device without first requiring authentication. 80. What is the purpose of banner? Banners are vital to provide a method for declaring that only authorized personnel should attempt to gain entry into the device. They can be an important part of the legal process in the event that someone is prosecuted for breaking into the device. 81. What is the command used to copy running configuration to NVRAM? Router # copy run start 82. Which command is used to encrypt the plain passwords in configuration file? Service password-encryption 83. What is the difference between ‘enable secret password’ and ‘enable password’? Enable secret password is encrypted and enable password is in plain text. 84. What are the ‘VTY’ lines? Virtual Teletype Lines used for telnet into a router. 85. Which password is encrypted by default? Enable Secret 86. Will login banner be displayed if console password is not set? No, because login banner is associated with console password. 87. What is NVRAM? Non-volatile random access memory. Data will not be deleted in case of power shut down. 88. What does this error mean? “Physical Link is administratively down.” Link is always administratively down by default. “No shutdown” command is used to activate the link. 89. What is the default factory name for switch? Switch 90. Which command is used to stop RIP routing updates to exit out an interface but still allow the interface to receive RIP route updates? Router (Config-router)#passive-interface s0 91. What are distance-vector and link-state routing protocols? Distance-vector sends its complete routing table out all active interfaces on periodic time intervals. Link-state sends updates containing the state of its own links to all routers in the internetwork. 92. 120 in [120/1] is ___ Administrative distance 93. Which command will create a dynamic pool lab that will provide you with 30 global addresses? ip nat pool lab 171.16.10.65 171.16.10.94 netmask 255.255.255.0 94. What command will be used in NAT for address before translation? Inside local 95. What command will be used in NAT for address after translation? Inside global 96. Which command would you place on interface on private network? Ip nat inside 97. Which command would you place on interface connected to the internet? Ip nat outside 98. Pat Address Translation is also termed what? NAT Overload 99. Which are considered the three methods of NAT? Static Dynamic Overload 100. What are advantages of using NAT? Conserves legally registered addresses. Increases flexibility when connecting to the internet. Reduces address overlap occurrence.