Saturday, 23 July 2016

100 Interview Question Answers For Computer Networking-Part3

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41. 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.
42. Why should you care about the OSI Reference Model?
It provides a framework for discussing network operations and design.
43. 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
44. What is MAU?
In token Ring , hub is called Multistation Access Unit(MAU).
45. 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.
46. 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.
47. What is the range of addresses in the classes of internet addresses?
Class A -
Class B -
Class C -
Class D -
Class E -
48. What is the minimum and maximum length of the header in the TCP segment and IP

The header should have a minimum length of 20 bytes and can have a maximum length of 60
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 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 are the data units at different layers of the TCP / IP protocol suite?
The data unit created at the application layer is called a message, at the transport layer the
data unit created is called either a segment or an user datagram, at the network layer the data
unit created is called the datagram, at the data link layer the datagram is encapsulated in to a
frame and finally transmitted as signals along the transmission media.
52. What is Project 802?
It is a project started by IEEE to set standards that enable intercommunication between
equipment from a variety of
manufacturers. It is a way for specifying functions of the physical layer, the data link layer and
to some extent the network layer to allow for interconnectivity of major LAN
It consists of the following:
802.1 is an internetworking standard for compatibility of different LANs and MANs across
802.2 Logical link control (LLC) is the upper sublayer of the data link layer which is nonarchitecture-
specific, that is
remains the same for all IEEE-defined LANs.
Media access control (MAC) is the lower sublayer of the data link layer that contains some
distinct modules each
carrying proprietary information specific to the LAN product
being used. The modules are Ethernet LAN (802.3), Token ring LAN (802.4), Token bus LAN
802.6 is distributed queue dual bus (DQDB) designed to be used in MANs.
53. What is Bandwidth?
Every line has an upper limit and a lower limit on the frequency of signals it can carry. This
limited range is called the
54. Difference between bit rate and baud rate.?
Bit rate is the number of bits transmitted during one second whereas baud rate refers to the
number of signal units per
second that are required to represent those bits.
baud rate = bit rate / N where N is no-of-bits represented by each signal shift.
The address for a device as it is identified at the Media Access Control (MAC) layer in the
network architecture. MAC
address is usually stored in ROM on the network adapter card and is unique.
56. What is attenuation?
The degeneration of a signal over distance on a network cable is called attenuation.
57. What is cladding
A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable.
58. What is RAID?
A method for providing fault tolerance by using multiple hard disk drives.
59. 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
60. 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.

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