1. List the layers in the OSI model that have associated hardware components
✔ Datalink layer – NIC Card
✔ Physical layer – Transmission cables
2. Define Round Trip Time
The time taken for a packet to travel from Sender to receiver and ACK passing back
from Receiver back to sender.
3. Mention the Factors that affect the performance of a network
✔ Bandwidth of the transmission medium.
✔ Type of network traffic.
✔ Network latency.
✔ Number of transmission errors.
4. Define Socket
A host local application created OS controlled interface into which application process
can both send and receive messages to/from another application process.
5. Calculate latency for a 1-Gbps Ethernet with a single store-and-forward switch in
the path, and a packet size of 5,000 bits. Assume that each link introduces a
propagation delay of 10 μs and that the switch begins retransmitting immediately
after it has finished receiving the packet.
Total delay = 10 μs + 5 μs = 15 μs
6. Compare Guided and Unguided Medium
Guided Medium
Wired medium
Signal energy propagates through wires in guided media
E.g.., Ethernet topologies – Coaxial cable, Twisted pair and fiber optics
Unguided medium
Wireless communication
Signal energy propagates through the air in unguided media
Radio waves, Infrared
7. State the major function performed by data link layer of the OSI model.
✔ Framing
✔ Physical addressing
✔ Flow control
, ✔ Error control
✔ Access control
✔ Node to Node Delivery
8. List the advantages of Bus Topology.
✔ Low cost
✔ Easy to expand
✔ Easy to Troubleshoot
9. Mention the use of bandwidth and latency in performance of network.
A bigger bandwidth is desirable because it allows more data to be sent at any given
time. Latency is primarily a measure of data speed. It tells you how long a data packet travels
between two points in a network. Lower latency is the goal because it means smaller delay and
smoother communication.
10. Define Protocol. Mention few protocols used in Application and Transport layers of OSI
model.
✔ Protocol is defined as the set of rules and regulations that governs the data communication.
✔ Application Layer : TELNET, FTP, SMTP, DNS, HTTP
✔ Transport Layer: TCP, UDP, SCTP
11. List the features provided by layering.
✔ Decomposes the problem into more manageable components
✔ It provides more modular design.
12. Compare half duplex and full duplex transmission modes.
Half duplex Full Duplex
Information can be sent in both Information can flow in both
direction but it doesnot allow both directions but it also can operate in
directions to operate at the same both directions at the same time.
time.
Higher performance than simplex Better performance than Half
duplex. duplex
Example: Walkie-Talkies Example: Telephone
13. Mention the use of Bandwidth and latency in performance of network.
Bandwidth of the network is defined as the number of bits that can be transmitted over
the network in a certain period of time.
Latency is a measure of how long a single bit takes to propogate from one end of a link
or channel or network to other end.
14. Consider a LAN with a maximum distance of 2 km. Find the bandwidth suitable for
transmitting 100-byte packet in a link of speed 2x108 m/s.
Bandwidth = size x speed of light/ Distance
i. = (100 x 8) bits x 2 x 108 m/s / 2000 m
ii. = 800x 105 bits/sec
15. List out the criteria necessary for an effective and efficient network.
The most important criteria are performance, reliability and security.
Performance of the network depends on number of users, type of transmission medium,
the capabilities of the connected h/w and the efficiency of the s/w. Reliability is
, measured by frequency of failure, the time it takes a link to recover from the failure and
the network’s robustness in a catastrophe. Security issues include protecting data from
unauthorized access and viruses.
16. Group the OSI layers by function.
The seven layers of the OSI model belonging to three subgroups. Network
support layers: Consisting of Physical, data link and network layers and they deal with
the physical aspects of moving data from one device to another. User support layers:
Consists of Session, presentation and application layers and they allow interoperability
among unrelated software systems. The transport layer ensures end-to-end reliable data
transmission
17. Mention the features provided by layering.
✔ It decomposes the problem of building a network into more manageable
components. Rather than implementing a monolithic piece of software that does
everything implement several layers, each of which solves one part of the
problem.
✔ It provides more modular design. To add some new service, it is enough to
modify the functionality at one layer, reusing the functions provided at all the
other layers.
18. List out the interfaces provided by protocols.
✔ Service interface
✔ Peer interface
✔ Service interface-defines the operations that local objects can perform on the
protocol.
✔ Peer interface-defines the form and meaning of messages exchanged between
protocol peers to implement the communication service.
19. Define LAN.
A LAN is a common name used to describe a group of devices that share a
geographic location. LAN is limited to single building or campus.
20. Define flow Control.
Flow control refers to a set of procedures used to restrict the amount of data.
The sender can send before waiting for acknowledgment.
21. State the criteria necessary for an effective and efficient network.
The most important criteria are performance, reliability and security.
Performance of
the network depends on number of users, type of transmission medium, the capabilities
of the connected h/w and the efficiency of the s/w.
22. List out the three fundamental characteristics determine the effectiveness of the
data communication system.
The effectiveness of the data communication system depends on 3 fundamental
characters:
✔ Delivery: The system must deliver data to the correct destination.
✔ Accuracy: The system must deliver data accurately.
✔ Timeliness: The system must deliver data in a timely manner.
, 23. Give reason why are protocols needed.
In networks, communication occurs between the entities in different systems.
Two entities cannot just send bit streams to each other and expect to be understood. For
communication, the entities must agree on a protocol. A protocol is a set of rules that
govern data communication.
24. For n devices in a network, what is the number of cable links required for a mesh
and ring topology?
Mesh topology – n (n-1)/2
Ring topology – n
25. Distinguish between peer-to-peer relationship and a primary-secondary
relationship.
✔ Peer-to-peer relationship: All the devices share the link equally.
✔ Primary-secondary relationship: One device controls traffic and the others must
transmit through it.
PART B
1. Compare and contrast the functionalities of each layer in OSI and TCP/IP model. Justify
why TCP/IP model is practically used in today’s internet.
OSI Architecture
Functionalities of OSI Lyaers
Application Layer
⮚ Network Virtual Terminal
⮚ FTAM File transfer access and management
⮚ Mail Services
⮚ Directory Services
Presentation Layer
⮚ Translation
⮚ Encryption/ Decryption
✔ Datalink layer – NIC Card
✔ Physical layer – Transmission cables
2. Define Round Trip Time
The time taken for a packet to travel from Sender to receiver and ACK passing back
from Receiver back to sender.
3. Mention the Factors that affect the performance of a network
✔ Bandwidth of the transmission medium.
✔ Type of network traffic.
✔ Network latency.
✔ Number of transmission errors.
4. Define Socket
A host local application created OS controlled interface into which application process
can both send and receive messages to/from another application process.
5. Calculate latency for a 1-Gbps Ethernet with a single store-and-forward switch in
the path, and a packet size of 5,000 bits. Assume that each link introduces a
propagation delay of 10 μs and that the switch begins retransmitting immediately
after it has finished receiving the packet.
Total delay = 10 μs + 5 μs = 15 μs
6. Compare Guided and Unguided Medium
Guided Medium
Wired medium
Signal energy propagates through wires in guided media
E.g.., Ethernet topologies – Coaxial cable, Twisted pair and fiber optics
Unguided medium
Wireless communication
Signal energy propagates through the air in unguided media
Radio waves, Infrared
7. State the major function performed by data link layer of the OSI model.
✔ Framing
✔ Physical addressing
✔ Flow control
, ✔ Error control
✔ Access control
✔ Node to Node Delivery
8. List the advantages of Bus Topology.
✔ Low cost
✔ Easy to expand
✔ Easy to Troubleshoot
9. Mention the use of bandwidth and latency in performance of network.
A bigger bandwidth is desirable because it allows more data to be sent at any given
time. Latency is primarily a measure of data speed. It tells you how long a data packet travels
between two points in a network. Lower latency is the goal because it means smaller delay and
smoother communication.
10. Define Protocol. Mention few protocols used in Application and Transport layers of OSI
model.
✔ Protocol is defined as the set of rules and regulations that governs the data communication.
✔ Application Layer : TELNET, FTP, SMTP, DNS, HTTP
✔ Transport Layer: TCP, UDP, SCTP
11. List the features provided by layering.
✔ Decomposes the problem into more manageable components
✔ It provides more modular design.
12. Compare half duplex and full duplex transmission modes.
Half duplex Full Duplex
Information can be sent in both Information can flow in both
direction but it doesnot allow both directions but it also can operate in
directions to operate at the same both directions at the same time.
time.
Higher performance than simplex Better performance than Half
duplex. duplex
Example: Walkie-Talkies Example: Telephone
13. Mention the use of Bandwidth and latency in performance of network.
Bandwidth of the network is defined as the number of bits that can be transmitted over
the network in a certain period of time.
Latency is a measure of how long a single bit takes to propogate from one end of a link
or channel or network to other end.
14. Consider a LAN with a maximum distance of 2 km. Find the bandwidth suitable for
transmitting 100-byte packet in a link of speed 2x108 m/s.
Bandwidth = size x speed of light/ Distance
i. = (100 x 8) bits x 2 x 108 m/s / 2000 m
ii. = 800x 105 bits/sec
15. List out the criteria necessary for an effective and efficient network.
The most important criteria are performance, reliability and security.
Performance of the network depends on number of users, type of transmission medium,
the capabilities of the connected h/w and the efficiency of the s/w. Reliability is
, measured by frequency of failure, the time it takes a link to recover from the failure and
the network’s robustness in a catastrophe. Security issues include protecting data from
unauthorized access and viruses.
16. Group the OSI layers by function.
The seven layers of the OSI model belonging to three subgroups. Network
support layers: Consisting of Physical, data link and network layers and they deal with
the physical aspects of moving data from one device to another. User support layers:
Consists of Session, presentation and application layers and they allow interoperability
among unrelated software systems. The transport layer ensures end-to-end reliable data
transmission
17. Mention the features provided by layering.
✔ It decomposes the problem of building a network into more manageable
components. Rather than implementing a monolithic piece of software that does
everything implement several layers, each of which solves one part of the
problem.
✔ It provides more modular design. To add some new service, it is enough to
modify the functionality at one layer, reusing the functions provided at all the
other layers.
18. List out the interfaces provided by protocols.
✔ Service interface
✔ Peer interface
✔ Service interface-defines the operations that local objects can perform on the
protocol.
✔ Peer interface-defines the form and meaning of messages exchanged between
protocol peers to implement the communication service.
19. Define LAN.
A LAN is a common name used to describe a group of devices that share a
geographic location. LAN is limited to single building or campus.
20. Define flow Control.
Flow control refers to a set of procedures used to restrict the amount of data.
The sender can send before waiting for acknowledgment.
21. State the criteria necessary for an effective and efficient network.
The most important criteria are performance, reliability and security.
Performance of
the network depends on number of users, type of transmission medium, the capabilities
of the connected h/w and the efficiency of the s/w.
22. List out the three fundamental characteristics determine the effectiveness of the
data communication system.
The effectiveness of the data communication system depends on 3 fundamental
characters:
✔ Delivery: The system must deliver data to the correct destination.
✔ Accuracy: The system must deliver data accurately.
✔ Timeliness: The system must deliver data in a timely manner.
, 23. Give reason why are protocols needed.
In networks, communication occurs between the entities in different systems.
Two entities cannot just send bit streams to each other and expect to be understood. For
communication, the entities must agree on a protocol. A protocol is a set of rules that
govern data communication.
24. For n devices in a network, what is the number of cable links required for a mesh
and ring topology?
Mesh topology – n (n-1)/2
Ring topology – n
25. Distinguish between peer-to-peer relationship and a primary-secondary
relationship.
✔ Peer-to-peer relationship: All the devices share the link equally.
✔ Primary-secondary relationship: One device controls traffic and the others must
transmit through it.
PART B
1. Compare and contrast the functionalities of each layer in OSI and TCP/IP model. Justify
why TCP/IP model is practically used in today’s internet.
OSI Architecture
Functionalities of OSI Lyaers
Application Layer
⮚ Network Virtual Terminal
⮚ FTAM File transfer access and management
⮚ Mail Services
⮚ Directory Services
Presentation Layer
⮚ Translation
⮚ Encryption/ Decryption
