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Computer Science (b) Modular design: Each layer in (c) Limited scope: The OSI model
the seven layers of the OSI model
might appear complicated for
the OSI model performs specific
functions and interacts with
simpler network setups.
adjacent layers through well-defined
interfaces. This modular design
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promotes interoperability between
communication and doesn’t
network devices from different primarily focuses on data
encompass broader network
vendors as long as they adhere to functionalities like security, network
the same standards at each layer. management, or application services.
(c) Flexibility: The layered approach
allows for independent development Communication between computers
and modification of protocols within in a network in OS model
each layer without affecting the
overall functionality of the model. When information is transmitted from
This flexibility facilitates the a software application on one computer
introduction of new technologies to an application on another computer,
and protocols without disrupting it follows the layers of the OSI model.
existing network infrastructure. For example, if computer A’s software
(d) Troubleshooting: By understanding application needs to send data to computer
the functionalities of each layer, B’s application, the process starts at the
network administrators can more application layer (Layer 7) on computer
effectively isolate and troubleshoot A. The data then goes through the
network problems. The layered presentation layer (Layer 6), session layer
structure helps pinpoint which layer (Layer 5), and so on, until it reaches the
is likely causing the issue, making physical layer (Layer 1). At this point,
troubleshooting more efficient. the data is transmitted over the physical
network medium to computer B.
Disadvantages of the OSI model Upon arrival at computer B, the data
(a) Theoretical model: The OSI model is moves up from the physical layer (Layer
a conceptual framework and does not 1) through the data link layer (Layer 2),
directly map to any specific real-world
network protocol implementations. network layer (Layer 3), and the remaining
While it provides a valuable layers until it reaches the application
foundation, actual protocols like TCP/ layer (Layer 7). The application layer on
IP may have different layer structures computer B then delivers the information
or combine the functionalities of to the intended application program,
multiple OSI layers. completing the communication process.
(b) Overly complex for some
applications: While beneficial for Each layer of the OSI model
understanding complex networks, communicates with its corresponding
layer on the other system using control
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for Advanced Secondary Schools
Computer Science Form 5.indd 126 23/07/2024 12:33
