Saturday, November 15, 2014

Nitheen Kumar

Networking Interview Question and Answers

1. Define Network?

A network is a set of devices connected by physical media links. A network is recursively is a connection of two or more nodes by a physical link or two or more networks connected by one or more nodes.

2. What is the criteria to check the network reliability?

A network Reliability is measured on following factors.

a) Downtime:

The time it takes to recover.

b) Failure Frequency:

The frequency when it fails to work the way it is intended.

3. What do you mean by Bandwidth?

Every Signal has a limit of its upper range and lower range of frequency of signal it can carry. This range of limit of network between its upper frequency and lower frequency is termed as Bandwidth.

4. What is a Link?

At the lowest level, a network can consist of two or more computers directly connected by some physical medium such as coaxial cable or optical fiber. Such a physical medium is called as Link.

5. What is a node?

A network can consist of two or more computers directly connected by some physical medium such as coaxial cable or optical fiber. Such a physical medium is called as Links and the computer it connects is called as Nodes.

6. What is a gateway or Router?

A node that is connected to two or more networks is commonly called as router or Gateway. It generally forwards message from one network to another.

7. What is DNS?

DNS stands for Domain Name System. It is a Naming System for all the resources over Internet which includes Physical nodes and Applications. DNS is a way to locate to a resource easily over a network and serves to be an essential component necessary for the working of Internet.

8. What is point-point link?

If the physical links are limited to a pair of nodes it is said to be point-point link.

9. What is DHCP scope?

A scope is a range, or pool, of IP addresses that can be leased to DHCP clients on a given subnet.

10. What is FQDN?

An FQDN contains (fully qualified domain name) both the hostname and a domain name. It uniquely identifies a host within a DNS hierarchy

11. What is the DNS forwarder?

DNS servers often must communicate with DNS servers outside of the local network. A forwarder is an entry that is used when a DNS server receives DNS queries that it cannot resolve locally. It then forwards those requests to external DNS servers for resolution.

12.Give a brief description of PAN, LAN, HAN, SAN, CAN, MAN, WAN, GAN.

a) PAN

(Personal Area Network) It is a connection of Computer and Devices that are close to a person VIZ., Computer, Telephones, Fax, Printers, etc. Range Limit – 10 meters.

b) LAN

(Local Area Network) LAN is the connection of Computers and Devices over a small Geographical Location – Office, School, Hospital, etc. A LAN can be connected to WAN using a gateway (Router).

c) HAN

(House Area Network) HAN is LAN of Home which connects to homely devices ranging from a few personal computers, phone, fax and printers.

d) SAN

(Storage Area Network) SAN is the connection of various storage devices which seems local to a computer.

e) CAN

(Campus Area Network) CAN is the connection of devices, printers, phones and accessories within a campus which Links to other departments of the organization within the same campus.

f) MAN

(Metropolitan Area Network) MAN is the connection of loads of devices which spans to Large cities over a wide Geographical Area.

g) WAN

( Wide Area Network) WAN connects devices, phones, printers, scanners, etc over a very wide geographical location which may range to connect cities, countries and ever continents.

h) GAN

(Global Area Network) GAN connects mobiles across the globe using satellites.

13.What is POP3?

POP3 stands for Post Office Protocol Version3 (Current Version). POP is a protocol which listens on port 110 and is responsible for accessing the mail service on a client machine. POP3 works in two modes such asDelete Mode and Keep Mode.

a) Delete Mode:

A mail is deleted from the mailbox after successful retrieval.


b) Keep Mode:

The Mail remains Intact in the mailbox after successful retrieval.

14. How would you recommend we support our mobile workers?

Look for answers that talk about bandwidth availability, user experience, and traffic security. It’s also interesting to see if candidates ask what sort of applications mobile workers use and then tailor their answers to reflect the way the network will be used.

15. What’s your experience of configuration management?

This question probes candidates' thoughts and experiences of the structure and governance that surrounds networking. You want someone with deep technical knowledge and domain experience, but also someone who isn’t a maverick who will make changes without following the proper protocols.

16. What do you mean by MAC address? Does it has some link or something in common to Mac OS of Apple?

MAC stands for Media Access Control. It is the address of the device identified at Media Access Control Layer of Network Architecture. Similar to IP address MAC address is unique address, i.e., no two device can have same MAC address. MAC address is stored at the Read Only Memory (ROM) of the device. MAC Address and Mac OS are two different things and it should not be confused with each other. Mac OS is a POSIX standard Operating System Developed upon FreeBSD used by Apple devices.
That’s all for now. We will be coming up with another articles on Networking series every now and then. Till then, don’t forget to provide us with your valuable feedback in the comment section below.

17. How will check ip address on 98?

Start ==> Run ==> command ==> winipcfg
How will you make partition after installing windows?
My computer ==> right click ==> manage ==> disk management ==>
select free space ==> right click ==> New partition

18. What is IP?

It's a unique 32 bits software address of a node in a network.

19. What is private IP?

Three ranges of IP addresses have been reserved for private address and they are not valid for use on the Internet. If you want to access internet with these address you must have to use proxy server or NAT server (on normal cases the role of proxy server is played by your ISP.).If you do decide to implement a private IP address range, you can use IP addresses from any of the following classes:

Class A :

10.0.0.0 10.255.255.255

Class B :

172.16.0.0 172.31.255.255

Class C :

192.168.0.0 192.168.255.255

20. What is public IP address?

A public IP address is an address leased from an ISP that allows or enables direct Internet communication.

21. What's the benefit of subnetting?
  1. Reduce the size of the routing tables.
  2. Reduce network traffic. Broadcast traffic can be isolated within a single logical network.
  3. Provide a way to secure network traffic by isolating it from the rest of the network.
22. What are the differences between static IPaddressing and dynamic IPaddressing?

With static IP addressing, a computer (or other device) is configured to always use the same IP address. With dynamic addressing, the IP address can change periodically and is managed by a centralized network service.

23.What is APIPA?

Automatic private IP addressing (APIPA) is a feature mainly found in Microsoft operating systems. APIPA enables clients to still communicate with other computers on the same network segment until an IP address can be obtained from a DHCP server, allowing the machine to fully participate on the network. The range of these IP address are the 169.254.0.1 to 169.254.255.254 with a default Class B subnet mask of 255.255.0.0.

24. What are the LMHOSTS files?

The LMHOSTS file is a static method of resolving NetBIOS names to IP addresses in the same way that the HOSTS file is a static method of resolving domain names into IP addresses. An LMHOSTS file is a text file that maps NetBIOS names to IP addresses; it must be manually configured and updated.

25. When were OSI model developed and why its standard called 802.XX and so on?

OSI model was developed in February1980 that why these also known as 802.XX Standard (Note : 80 means ----> 1980, 2means ----> February)

26. What is Full form of ADS?

Active Directory Structure

27. How will you register and activate windows?

If you have not activated windows XP, you can do so at any time by clicking the windows Activation icon in the system tray to initiate activation. Once you have activated windows XP, this icon disappears from the system tray. For registration Start ==> Run ==> regwiz /r

28. Where do we use cross and standard cable?

Computer to computer ==> cross Switch/hub to switch/hub ==>cross Computer to switch/hub ==>standard

29.What is RAID?

A method for providing fault tolerance by using multiple hard disk drives.

30.What is NETBIOS and NETBEUI?

NETBIOS is a programming interface that allows I/O requests to be sent to and received from a remote computer and it hides the networking hardware from applications.
NETBEUI is NetBIOS extended user interface. A transport protocol designed by Microsoft and IBM for the use on small subnets.

31.What is redirector?

Redirector is software that intercepts file or prints I/O requests and translates them into network requests. This comes under presentation layer.

32.What is Beaconing?

The process that allows a network to self-repair networks problems. The stations on the network notify the other stations on the ring when they are not receiving the transmissions. Beaconing is used in Token ring and FDDI networks.

33.How will enable sound service in 2003?

By default this service remain disable to enable this service
Start -------->administrative tools ---------> service -----------> windows audio ----------> start up type -------->automatic

34. How will enable CD burning service in 2003?

By default this service remain disable to enable this service
Start --------> administrative tools --------> service -------->IMAPI CD burning com service --------> start up type --------> automatic

35. What types of network do you have experience with?

This should be one of the first things you ask. It might be critical to you that the candidate has prior experience with the type of network model you use, but even candidates that don't could be good fits, assuming they are willing to learn and have other critical skills. In fact, candidates with lots of experience on networks very similar to yours could be too set in their ways to adapt to the way your business does things.

36. What can you tell me about the OSI Reference Model?

The OSI Reference Model provides a framework for discussing network design and operations. It groups communication functions into 7 logical layers, each one building on the next. This question will demonstrate whether candidates have the theoretical knowledge to back up their practical skills.

37.What are the use of cross and standard cables? Where do you find their usages?

A Network cable may be crossover as well as straight. Both of these cables have different wires arrangement in them, which serves to fulfill different purpose.

a) Area of application of Straight cable
  1. Computer to Switch
  2. Computer to Hub
  3. Computer to Modem
  4. Router to Switch
b) Ares of application of Crossover cable
  1. Computer to Computer
  2. Switch to Switch
  3. Hub to Hub
38. What monitoring tools or approaches do you rate?

You can extend this to ask about what tools candidates have used in other jobs. Hopefully they will be able to give you a range of products and techniques, and the rationale for their favorites. This can tell you about the depth of their experience and also whether their choices of tools are a good fit for your architecture.

39. Describe 802.3 standards
  1. IEEE 802 : LAN/MAN
  2. IEEE 802.1 :Standards for LAN/MAN bridging and management and remote media access control bridging.
  3. IEEE 802.2 :Standards for Logical Link Control (LLC) standards for connectivity.
  4. IEEE 802.3 :Ethernet Standards for Carrier Sense Multiple Access with Collision Detection (CSMA/CD).
  5. IEEE 802.4 :Standards for token passing bus access.
  6. IEEE 802.5 :Standards for token ring access and for communications between LANs and MANs
  7. IEEE 802.6 :Standards for information exchange between systems.
  8. IEEE 802.7 : Standards for broadband LAN cabling.
  9. IEEE 802.8 : Fiber optic connection.
  10. IEEE 802.9 : Standards for integrated services, like voice and data.
  11. IEEE 802.10 : Standards for LAN/MAN security implementations.
  12. IEEE 802.11 : Wireless Networking – "WiFi".
  13. IEEE 802.12 : Standards for demand priority access method.
  14. IEEE 802.14 : Standards for cable television broadband communications.
  15. IEEE 802.15.1 : Bluetooth
  16. IEEE 802.15.4 : Wireless Sensor/Control Networks – "ZigBee"
  17. IEEE 802.16 : Wireless Networking – "WiMAX"
40. What is virtual path?

Along any transmission path from a given source to a given destination, a group of virtual circuits can be grouped together into what is called path.

41. What is virtual channel?

Virtual channel is normally a connection from one source to one destination, although multicast connections are also permitted. The other name for virtual channel is virtual circuit.

42. What is logical link control?

One of two sublayers of the data link layer of OSI reference model, as defined by the IEEE 802 standard. This sublayer is responsible for maintaining the link between computers when they are sending data across the physical network connection.

43. Why should you care about the OSI Reference Model?

It provides a framework for discussing network operations and design.

44. What is the difference between routable and non- routable protocols?

Routable protocols can work with a router and can be used to build large networks. Non-Routable protocols are designed to work on small, local networks and cannot be used with a router

45. What is MAU?

In token Ring , hub is called Multistation Access Unit(MAU).

46. Explain 5-4-3 rule

In a Ethernet network, between any two points on the network, there can be no more than five network segments or four repeaters, and of those five segments only three of segments can be populated.

47. What is the difference between TFTP and FTP application layer protocols?

The Trivial File Transfer Protocol (TFTP) allows a local host to obtain files from a remote host but does not provide reliability or security. It uses the fundamental packet delivery services offered by UDP. The File Transfer Protocol (FTP) is the standard mechanism provided by TCP / IP for copying a file from one host to another. It uses the services offered by TCP and so is reliable and secure. It establishes two connections (virtual circuits) between the hosts, one for data transfer and another for control information.

48. What is the minimum and maximum length of the header in the TCP segment and IP datagram?

The header should have a minimum length of 20 bytes and can have a maximum length of 60 bytes.

49. What is difference between ARP and RARP?

The address resolution protocol (ARP) is used to associate the 32 bit IP address with the 48 bit physical address, used by a host or a router to find the physical address of another host on its network by sending a ARP query packet that includes the IP address of the receiver.
The reverse address resolution protocol (RARP) allows a host to discover its Internet address when it knows only its physical address.

50. What is ICMP?

ICMP is Internet Control Message Protocol, a network layer protocol of the TCP/IP suite used by hosts and gateways to send notification of datagram problems back to the sender. It uses the echo test / reply to test whether a destination is reachable and responding. It also handles both control and error messages.

51.What is terminal emulation, in which layer it comes?

Telnet is also called as terminal emulation. It belongs to application layer.

52. What is frame relay, in which layer it comes?

Frame relay is a packet switching technology. It will operate in the data link layer.

53. What do you meant by "triple X" in Networks?

The function of PAD (Packet Assembler Disassembler) is described in a document known as X.3. The standard protocol has been defined between the terminal and the PAD, called X.28; another standard protocol exists between hte PAD and the network, called X.29. Together, these three recommendations are often called "triple X".

54. What is SAP?

Series of interface points that allow other computers to communicate with the other layers of network protocol stack.

55. What is subnet?

A generic term for section of a large networks usually separated by a bridge or router.

56. What is subnet mask?

It is a term that makes distinguish between network address and host address in IP address. Subnet mask value 0 defines host partition in IP address and value 1 – 255 defines Network address.

57.What is backbone network?

A backbone network is a centralized infrastructure that is designed to distribute different routes and data to various networks. It also handles management of bandwidth and various channels.

58. What is anonymous FTP?

Anonymous FTP is a way of granting user access to files in public servers. Users that are allowed access to data in these servers do not need to identify themselves, but instead log in as an anonymous guest.

59. What is subnet mask?

A subnet mask is combined with an IP address in order to identify two parts: the extended network address and the host address. Like an IP address, a subnet mask is made up of 32 bits.

60. What is the maximum length allowed for a UTP cable?

A single segment of UTP cable has an allowable length of 90 to 100 meters. This limitation can be overcome by using repeaters and switches.

61. What is data encapsulation?

Data encapsulation is the process of breaking down information into smaller manageable chunks before it is transmitted across the network. It is also in this process that the source and destination addresses are attached into the headers, along with parity checks.

62. Describe Network Topology

Network Topology refers to the layout of a computer network. It shows how devices and cables are physically laid out, as well as how they connect to one another.

63.What is VPN?

VPN means Virtual Private Network, a technology that allows a secure tunnel to be created across a network such as the Internet. For example, VPNs allow you to establish a secure dial-up connection to a remote server.

64. Briefly describe NAT.

NAT is Network Address Translation. This is a protocol that provides a way for multiple computers on a common network to share single connection to the Internet.


65. How does a network topology affect your decision in setting up a network?

Network topology dictates what media you must use to interconnect devices. It also serves as basis on what materials, connector and terminations that is applicable for the setup.

66. What is RIP?

RIP, short for Routing Information Protocol is used by routers to send data from one network to another. It efficiently manages routing data by broadcasting its routing table to all other routers within the network. It determines the network distance in units of hops.

67.What are different ways of securing a computer network?

There are several ways to do this. Install reliable and updated anti-virus program on all computers. Make sure firewalls are setup and configured properly. User authentication will also help a lot. All of these combined would make a highly secured network.

68. What is NIC?

NIC is short for Network Interface Card. This is a peripheral card that is attached to a PC in order to connect to a network. Every NIC has its own MAC address that identifies the PC on the network.

69. What is the importance of the OSI Physical Layer?

The physical layer does the conversion from data bits to electrical signal, and vice versa. This is where network devices and cable types are considered and setup.

70. How many layers are there under TCP/IP?

There are four layers: the Network Layer, Internet Layer, Transport Layer and Application Layer.

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