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Networking Interview Questions-2

Networking Interview Questions-2

Networking Interview Questions


What is Mail Gateway ?

It is a system that performs a protocol translation between different electronic mail delivery

What is wide-mouth frog ?

Wide-mouth frog is the simplest known key distribution center (KDC) authentication protocol.

What are Diagrams and Trigrams ?

The most common two letter combinations are called as diagrams. e.g. th, in, er, re and an. The
most common three letter combinations are called as trigrams. e.g. the, ing,
and, and ion.

What is silly window syndrome ?

It is a problem that can ruin TCP performance. This problem occurs when data are passed to
the sending TCP entity in large blocks, but an interactive application on the
receiving side reads 1 byte at a time.

What is region ?

When hierarchical routing is used, the routers are divided into what we call regions, with each
router knowing all the details about how to route packets to destinations
within its own region, but knowing nothing about the internal structure of other regions.

What is multicast routing

Sending a message to a group is called multicasting, and its routing algorithm is called
multicast routing.

What is traffic shaping ?

One of the main causes of congestion is that traffic is often busy. If hosts could be made to
transmit at a uniform rate,congestion would be less common. Another open loop
method to help manage congestion is forcing the packet to be transmitted at a more
predictable rate. This is called traffic shaping.

What is packet filter ?

Packet filter is a standard router equipped with some extra functionality. The extra
functionality allows every incoming or outgoing packet to be inspected. Packets meeting
some criterion are forwarded normally. Those that fail the test are dropped.

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.
Shwetank Kumar Gupta 2011

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.

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.

Why should you care about the OSI Reference Model

It provides a framework for discussing network operations and design.
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. NonRoutable
protocols are designed to work on small, local networks and cannot be used with a

What is MAU

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

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.

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.

What is the range of addresses in the classes of internet addresses

Class A –
Class B –
Class C –
Class D –
Class E –

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

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.

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.

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.

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.

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

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.
What is MAC address

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.

What is attenuation

The degeneration of a signal over distance on a network cable is called attenuation.

What is cladding

A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable.

What is RAID

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


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

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