|
|
|
Search for
C,C++,DAA Programs. Send video songs to your loved ones.
|
|
Custom Search
|
|
|
|
|
|
Shaadi.com Matrimonials
|
Computer Networks - Page 1
Page1 ||
Page2
|| Page3
|
|
|
Qusetion1: What are the various physical media
used for the data transmission in various networks system?
Answer: Type of transmission media are :-
Twisted Pair Cable : A twisted pair is an inexpensive transmission
media. It consists of two insulated copper wires twisted in a spiral
pattern. One pair acts as a single communication link. A bunch of
hundreds of such pairs is packed into a cable that carries signals over
longer distance.
Coaxial Cable : A coaxial cable is made up of central copper wire
surrounded by a conductive sleeve separated by insulation. The
insulation is either regular spaced ring or a solid dielectric material
such as polythene filler.
Optical Fiber : An optical fiber is a thin strand of light conducting
glass or plastic fiber. The fiber is a flexible cylinder of size 2 to125
m that acts as the transmission medium of pulses of light carrying
data. The optical fiber cable has three sections : core, cladding and
the jacket. Generally multiple strands are bundle in a jacket.
Question2 : What are the different switching
techniques employed to provide communication between computers?
Answer: The different switching techniques employed to provide
communication between computers are.
(a) Circuit Switching : When a computer places a telephone call, the
switching equipment within the telephone system seeks out a physical
copper path all the way from the sender telephone to the receiver’s
telephone. In general, an important property of it is to setup an end to
end path before any data can be send
(b) Message Switching : In this form of switching no physical copper
path is established in advance between sender and receiver. Instant when
the sender has a block of data to be sent, it is stored in first
switching office, then forwarded later, one jump at a time.
(c) Packet switching : With message switching their is no limit on block
size, in contrast packet switching places a tight upper limit on block
size.
Question3 : Define various types of Topologies.
Answer : There are 3 types of Topologies in network they are :-
• Linear Bus Topology
• Ring Topology
• Star Topology
1. Linear Bus Topology : A bus structure usually uses a main trunk
called a backbone. It is a long Twisted Pair or Coaxial Cable into which
the peripheral or PC are connected with the help of short cables called
Drop Cables. A peripheral or PC are connected to the backbone or bus is
commonly known as a Node. The two ends of the backbone cable are
terminated at both ends by Absorbers.
The Advantages Of Bus Topology:
|
|
|
i. A wide range of equipments can be attached to the LAN without
problem.
ii. A new Node can be added to the LAN without disturbing the network
and other Nodes.
iii. Low cabling cost
The Limitation’s Of Bus Topology:
i. Only a single message can travel at a time.
ii. When a message from two Nodes comes on the line, a collision occurs.
The chances of collisions taking place are always there.
iii. Low reliability – a break or short circuit in the cable can halt
the whole network.
EXAMPLE : Ethernet is a very widely used bus topology LAN.
Picture Bus topology
2. Ring Topology : A Ring also known as Daisy Chain, is a large circular
cable. The ring can be twisted pair, coaxial cable s, or optic fiber.
All nodes can connect together in a ring and all data and information
passes through each node in the system. The NIC at each node regenerates
each input signal that travels around the ring. Thus, separate repeaters
are not required in this topology.
The Advantages Of Ring Topology:
i. One node can transmit at a time and, therefore, collision do not
occur
ii. The need of separate repeater is reduced.
The Limitation’s Of Ring Topology:
i. Each node must handle the data being transferred by other nodes.
ii. If one node fails to handle the transfer of data or a NIC goes bad
then whole of network fails.
|
|
|
|
EXAMPLE : Martinet uses ring topology LAN. Token Ring is another example
of this topology.
Picture Ring Topology
3. Star Topology : In a star topology, the various nodes are directly
wired to a central, dedicated computer called Hub of the star. The drop
cables extend in all directions and each device is connected to the hub
via these cables. The data from one node travels over the drop cable to
the hub and from hub, it travels to the destined node via another drop
cable.
The Advantages Of Star Topology:
i. If a node stops working, the LAN continuous uninterruptedly.
ii. Network management is easy.
The Limitation’s Of Star Topology:
i. If the hub crashes, whole of network fails.
ii. More of cabling is needed as compared to Bus or Ring Topology.
EXAMPLE : Arc net can be configured as a star topology LAN.
Picture Star Topology
|
|
Next
|
|
