Networking
1.
What are the two types of
transmission technology available?
(i)
Broadcast and (ii) point-to-point
2.
What is subnet?
A
generic term for section of a large networks usually separated by a bridge or
router.
3.
Difference between the communication
and transmission.
Transmission
is a physical movement of information and concern issues like bit polarity,
synchronizations, clock etc.
Communication
means the meaning full exchange of information between two communication media.
4.
What are the possible ways of data
exchange?
(i)
Simplex (ii) Half-duplex (iii) Full-duplex.
5.
What is SAP?
Series
of interface points that allow other computers to communicate with the other
layers of network protocol stack.
6.
What do you meant by "triple
X" in Networks?
The
function of PAD (Packet Assembler Dissembler) 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 the PAD and the
network, called X.29. Together, these three recommendations are often called
"triple X"
7.
What is frame relay, in which layer
it comes?
Frame relay is a packet
switching technology. It will operate in the data link layer.
8.
What is terminal emulation, in
which layer it comes?
Telnet
is also called as terminal emulation. It belongs to application layer.
9.
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.
10.
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.
11.
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.
12.
What is RAID?
A
method for providing fault tolerance by using multiple hard disk drives.
13.
What is passive topology?
When
the computers on the network simply listen and receive the signal, they are
referred to as passive because they don’t amplify the signal in any way.
Example for passive topology - linear bus.
14.
What is Brouter?
Hybrid
devices that combine the features of both bridges and routers.
15.
What is cladding?
A
layer of a glass surrounding the center fiber of glass inside a fiber-optic
cable.
16.
What is point-to-point protocol
A
communications protocol used to connect computers to remote networking services
including Internet service providers.
17.
How Gateway is different from
Routers?
A
gateway operates at the upper levels of the OSI model and translates
information between two completely different network architectures or data
formats
18.
What is attenuation?
The
degeneration of a signal over distance on a network cable is called attenuation.
19.
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.
20. 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.
21. 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 bandwidth.
22. What are the
types of Transmission media?
Signals are usually transmitted over some transmission
media that are broadly classified in to two categories.
a)
Guided Media:
These are those that provide a conduit from one device to
another that include twisted-pair, coaxial cable and fiber-optic cable. A
signal traveling along any of these media is directed and is contained by the
physical limits of the medium. Twisted-pair and coaxial cable use metallic that
accept and transport signals in the form of electrical current. Optical fiber
is a glass or plastic cable that accepts and transports signals in the form of
light.
b)
Unguided Media:
This is the wireless media that transport electromagnetic
waves without using a physical conductor. Signals are broadcast either through
air. This is done through radio communication, satellite communication and
cellular telephony.
23. What is Project 802?
It is a project started by IEEE to set standards to
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
protocols.
It consists of the following:
Ø
802.1 is an
internetworking standard for compatibility of different LANs and MANs across
protocols.
Ø
802.2 Logical link
control (LLC) is the upper sublayer of the data link layer which is
non-architecture-specific, that is remains the same for all IEEE-defined LANs.
Ø
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 (802.5).
Ø
802.6 is distributed
queue dual bus (DQDB) designed to be used in MANs.
24. What is Protocol Data Unit?
The data unit in the LLC level is called the protocol
data unit (PDU). The PDU contains of four fields a destination service access
point (DSAP), a source service access point (SSAP), a control field and an
information field. DSAP, SSAP are addresses used by the LLC to identify the
protocol stacks on the receiving and sending machines that are generating and
using the data. The control field specifies whether the PDU frame is a
information frame (I - frame) or a supervisory frame (S - frame) or a unnumbered
frame (U - frame).
25. What are the different type of networking / internetworking devices?
Repeater:
Also called a regenerator, it is an electronic device
that operates only at physical layer. It receives the signal in the network
before it becomes weak, regenerates the original bit pattern and puts the
refreshed copy back in to the link.
Bridges:
These operate both in the physical and data link layers
of LANs of same type. They divide a larger network in to smaller segments. They
contain logic that allow them to keep the traffic for each segment separate and
thus are repeaters that relay a frame only the side of the segment containing
the intended recipent and control congestion.
Routers:
They relay packets among multiple interconnected networks
(i.e. LANs of different type). They operate in the physical, data link and
network layers. They contain software that enable them to determine which of
the several possible paths is the best for a particular transmission.
Gateways:
They relay packets among networks that have different
protocols (e.g. between a LAN and a WAN). They accept a packet formatted for
one protocol and convert it to a packet formatted for another protocol before
forwarding it. They operate in all seven layers of the OSI model.
26. 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.
27. 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.
28. 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.
29.
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.
30. What is the range of addresses in the classes of internet addresses?
Class A 0.0.0.0 - 127.255.255.255
Class B 128.0.0.0 - 191.255.255.255
Class C 192.0.0.0 - 223.255.255.255
Class D 224.0.0.0 - 239.255.255.255
Class E 240.0.0.0 - 247.255.255.255
31. 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 offer 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.
32.
What are major types of networks
and explain?
Ø Server-based network
Ø Peer-to-peer network
Peer-to-peer network,
computers can act as both servers sharing resources and as clients using the
resources.
Server-based networks
provide centralized control of network resources and rely on server computers
to provide security and network administration
33.
What are the important topologies
for networks?
Ø BUS topology:
In this each computer
is directly connected to primary network cable in a single line.
Advantages:
Inexpensive,
easy to install, simple to understand, easy to extend.
Ø STAR topology:
In this all
computers are connected using a central hub.
Advantages:
Can
be inexpensive, easy to install and reconfigure and easy to trouble shoot
physical problems.
Ø RING topology:
In
this all computers are connected in loop.
Advantages:
All
computers have equal access to network media, installation can be simple, and
signal does not degrade as much as in other topologies because each computer
regenerates it.
34.
What is mesh network?
A network in which
there are multiple network links between computers to provide multiple paths
for data to travel.
35.
What is difference between baseband
and broadband transmission?
In a baseband
transmission, the entire bandwidth of the cable is consumed by a single signal.
In broadband transmission, signals are sent on multiple frequencies, allowing
multiple signals to be sent simultaneously.
36.
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.
37.
What MAU?
In token Ring , hub is
called Multistation Access Unit(MAU).
38.
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
39.
Why should you care about the OSI
Reference Model?
It provides a framework
for discussing network operations and design.
40.
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.
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 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.
43. 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.
44. 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.
45. What is multicast routing?
Sending
a message to a group is called multicasting, and its routing algorithm is
called multicast routing.
46. What is region?
When
hierarchical routing is used, the routers are divided into what we will 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.
47. 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.
48. What are Digrams
and Trigrams?
The
most common two letter combinations are called as digrams. 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.
49. Expand IDEA.
IDEA
stands for International Data Encryption Algorithm.
50. What is
wide-mouth frog?
Wide-mouth
frog is the simplest known key distribution center (KDC) authentication
protocol.
51.
What is Mail Gateway?
It is a system that
performs a protocol translation between different electronic mail delivery
protocols.
52.
What is IGP (Interior Gateway
Protocol)?
It is any routing
protocol used within an autonomous system.
53.
What is EGP (Exterior Gateway
Protocol)?
It is the protocol the
routers in neighboring autonomous systems use to identify the set of networks
that can be reached within or via each autonomous system.
54.
What is autonomous system?
It is a collection of
routers under the control of a single administrative authority and that uses a
common Interior Gateway Protocol.
55.
What is BGP (Border Gateway
Protocol)?
It is a protocol used
to advertise the set of networks that can be reached with in an autonomous
system. BGP enables this information to be shared with the autonomous system.
This is newer than EGP (Exterior Gateway Protocol).
56.
What is Gateway-to-Gateway
protocol?
It is a protocol
formerly used to exchange routing information between Internet core routers.
57.
What is NVT (Network Virtual
Terminal)?
It is a set of rules
defining a very simple virtual terminal interaction. The NVT is used in the
start of a Telnet session.
58.
What is a Multi-homed Host?
It is a host that has a
multiple network interfaces and that requires multiple IP addresses is called
as a Multi-homed Host.
59.
What is Kerberos?
It is an authentication
service developed at the Massachusetts Institute of Technology. Kerberos uses
encryption to prevent intruders from discovering passwords and gaining
unauthorized access to files.
60.
What is OSPF?
It is an Internet
routing protocol that scales well, can route traffic along multiple paths, and
uses knowledge of an Internet's topology to make accurate routing decisions.
61.
What is Proxy ARP?
It is using a router to
answer ARP requests. This will be done when the originating host believes that
a destination is local, when in fact is lies beyond router.
62.
What is SLIP (Serial Line Interface
Protocol)?
It is a very simple
protocol used for transmission of IP datagrams across a serial line.
63.
What is RIP (Routing Information
Protocol)?
It is a simple protocol
used to exchange information between the routers.
64.
What is source route?
It is a sequence of IP
addresses identifying the route a datagram must follow. A source route may
optionally be included in an IP datagram header.
