Subject Name: Computer Networking Subject Code: 4340703
UNIT 1 Basics of Computer Network
Q-1: Explain characteristics of computer network.
Communication speed
Network provides us to communicate over the network in a fast and efficient manner.
File sharing
File sharing is one of the major advantages of the computer network. Computer network provides us to
share the files with each other.
Back up and Roll back is easy
Since the files are stored in the main server which is centrally located. Therefore, it is easy to take the
back up from the main server.
Software and Hardware sharing
We can install the applications on the main server; therefore, the user can access the applications
centrally. So, we do not need to install the software on every machine. Similarly, hardware can also be
shared
Security
Network allows the security by ensuring that the user has the right to access the certain files and
applications.
Scalability
Scalability means that we can add the new components on the network. Network must be scalable so that
we can extend the network by adding new devices. But, it decreases the speed of the connection and data
of the transmission speed also decreases, this increases the chances of error occurring. This problem can
be overcome by using the routing or switching devices.
Reliability
Computer network can use the alternative source for the data communication in case of any hardware
failure.
Q-2 What is proxy server? Write its two Advantage and Disadvantage.
proxy server
A proxy server is which service the requests of its client by forwarding requests to other server
A client connects to the proxy server requesting some service such as file connection, webpage, or
other resource available from a different server.
A proxy server provides the resource by connecting to the specified server and requesting the service
on behalf of the client.
A server that sits between a client application such as a web browser and a real server.
Proxy server is a computer that acts as getaway between a local network and internet with in company
Prepared By: Department of Computer Engineering Page 1
,Subject Name: Computer Networking Subject Code: 4340703
Advantage
Provide a fast internet experience
Reduce the bandwidth consumed over the internet link
Disadvantage
Not cost effective for low bandwidth internet use.
Can be sticky setup
Q-3 Explain BUS, STAR and RING Topology.
Bus Topology:
In this arrangement, the nodes (computers) are connected through interface connectors to a single
communication line (central cable) that carries the message in both the directions.
The central cable to which all the nodes are connected is the backbone of the network. It is called a
bus.
The signal in this arrangement travels in both directions to all the machines until it finds the recipient
machine.
It is easy to set up than other topologies as it uses only a single central cable to establish the network.
Advantages:
Configuration of the network is easy.
Less costly because a single cable is used to connect all nodes.
The Bus topology supports a maximum of 10 Mbps speed by using the network's coaxial or twisted pair
cables.
Disadvantages
Due to the multipoint communication model, it is difficult to identify and isolate the faulty terminals.
The reconfiguration will affect the network and slows down the performance.
Prepared By: Department of Computer Engineering Page 2
,Subject Name: Computer Networking Subject Code: 4340703
Signal interference is another drawback of the bus topology; if two or more nodes transmit the messages
simultaneously, their signals will collide.
A single node failure also causes the breakdown of the whole network.
Star Topology
in Star Topology, all the devices are connected to a single hub through a cable.
This hub is the central node and all other nodes are connected to the central node.
The hub can be passive in nature
Coaxial cables or RJ-45 cables are used to connect the computers.
Passive hub: - passive hub not amplify received signal but it is forwarded that signal as it is. And passive
hub does not required electric power
Active hub: active hub amplify the received signal and forwarded to that signal next device active required
the electrical power to run. active also called multiport repeater.
Advantages of star topology
Centralized management of the network through the use of the central computer, hub, or switch.
Easy to add another computer to the network.
If one computer on the network fails, the rest of the network continues to function normally.
Prepared By: Department of Computer Engineering Page 3
, Subject Name: Computer Networking Subject Code: 4340703
Disadvantages of star topology
It may have a higher cost to implement, especially when using a switch or router as the central network
device.
The central network device determines the performance and number of nodes the network can handle.
If the central computer, hub, or switch fails, the entire network goes down, and all computers are
disconnected from the network.
Ring Topology
In a ring topology, each node is linked with its neighbor to form a closed network.
This configuration see the data move from one node to another, either unidirectionally or bidirectionally.
Such network topology is used in smaller networks, like those in schools.
Token passing is a method of sending data in ring which system has token then server send packet to that
system. After completion of data transfer token passing to another device those system want to transfer
data it wait for token.
Advantages
The data transmission is high-speed.
The possibility of collision is minimum in this type of topology.
Cheap to install and expand.
It is less costly than a star topology.
Prepared By: Department of Computer Engineering Page 4
UNIT 1 Basics of Computer Network
Q-1: Explain characteristics of computer network.
Communication speed
Network provides us to communicate over the network in a fast and efficient manner.
File sharing
File sharing is one of the major advantages of the computer network. Computer network provides us to
share the files with each other.
Back up and Roll back is easy
Since the files are stored in the main server which is centrally located. Therefore, it is easy to take the
back up from the main server.
Software and Hardware sharing
We can install the applications on the main server; therefore, the user can access the applications
centrally. So, we do not need to install the software on every machine. Similarly, hardware can also be
shared
Security
Network allows the security by ensuring that the user has the right to access the certain files and
applications.
Scalability
Scalability means that we can add the new components on the network. Network must be scalable so that
we can extend the network by adding new devices. But, it decreases the speed of the connection and data
of the transmission speed also decreases, this increases the chances of error occurring. This problem can
be overcome by using the routing or switching devices.
Reliability
Computer network can use the alternative source for the data communication in case of any hardware
failure.
Q-2 What is proxy server? Write its two Advantage and Disadvantage.
proxy server
A proxy server is which service the requests of its client by forwarding requests to other server
A client connects to the proxy server requesting some service such as file connection, webpage, or
other resource available from a different server.
A proxy server provides the resource by connecting to the specified server and requesting the service
on behalf of the client.
A server that sits between a client application such as a web browser and a real server.
Proxy server is a computer that acts as getaway between a local network and internet with in company
Prepared By: Department of Computer Engineering Page 1
,Subject Name: Computer Networking Subject Code: 4340703
Advantage
Provide a fast internet experience
Reduce the bandwidth consumed over the internet link
Disadvantage
Not cost effective for low bandwidth internet use.
Can be sticky setup
Q-3 Explain BUS, STAR and RING Topology.
Bus Topology:
In this arrangement, the nodes (computers) are connected through interface connectors to a single
communication line (central cable) that carries the message in both the directions.
The central cable to which all the nodes are connected is the backbone of the network. It is called a
bus.
The signal in this arrangement travels in both directions to all the machines until it finds the recipient
machine.
It is easy to set up than other topologies as it uses only a single central cable to establish the network.
Advantages:
Configuration of the network is easy.
Less costly because a single cable is used to connect all nodes.
The Bus topology supports a maximum of 10 Mbps speed by using the network's coaxial or twisted pair
cables.
Disadvantages
Due to the multipoint communication model, it is difficult to identify and isolate the faulty terminals.
The reconfiguration will affect the network and slows down the performance.
Prepared By: Department of Computer Engineering Page 2
,Subject Name: Computer Networking Subject Code: 4340703
Signal interference is another drawback of the bus topology; if two or more nodes transmit the messages
simultaneously, their signals will collide.
A single node failure also causes the breakdown of the whole network.
Star Topology
in Star Topology, all the devices are connected to a single hub through a cable.
This hub is the central node and all other nodes are connected to the central node.
The hub can be passive in nature
Coaxial cables or RJ-45 cables are used to connect the computers.
Passive hub: - passive hub not amplify received signal but it is forwarded that signal as it is. And passive
hub does not required electric power
Active hub: active hub amplify the received signal and forwarded to that signal next device active required
the electrical power to run. active also called multiport repeater.
Advantages of star topology
Centralized management of the network through the use of the central computer, hub, or switch.
Easy to add another computer to the network.
If one computer on the network fails, the rest of the network continues to function normally.
Prepared By: Department of Computer Engineering Page 3
, Subject Name: Computer Networking Subject Code: 4340703
Disadvantages of star topology
It may have a higher cost to implement, especially when using a switch or router as the central network
device.
The central network device determines the performance and number of nodes the network can handle.
If the central computer, hub, or switch fails, the entire network goes down, and all computers are
disconnected from the network.
Ring Topology
In a ring topology, each node is linked with its neighbor to form a closed network.
This configuration see the data move from one node to another, either unidirectionally or bidirectionally.
Such network topology is used in smaller networks, like those in schools.
Token passing is a method of sending data in ring which system has token then server send packet to that
system. After completion of data transfer token passing to another device those system want to transfer
data it wait for token.
Advantages
The data transmission is high-speed.
The possibility of collision is minimum in this type of topology.
Cheap to install and expand.
It is less costly than a star topology.
Prepared By: Department of Computer Engineering Page 4
