OSI Model and TCP/IP Protocol Suite

Running head: ASSIGNMENT 1
ASSIGNMENT 1
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1. OSI model has seven layers; these layers include physical layer, data link layer,
network layer, transport layer, session layer, presentation layer and application (Alani,
2014). These layers are placed between 1- 7 where the physical layer is placed at first
and application layer is placed at number 7.
Figure 1: the 7 layers of OSI
(Source: Alhamedi, Snasel & Aldosari, 2014, P. 132)
The TCP/IP protocol suite consists of five layers, these are physical, network,
application, and data link and transport layer. Physical, data, network and transport
layers provide network interfaced, physical standards, transport functions and
internetworking which corresponds four layers of OSI model that are present at the
top (Andrysiak, Saganowski&Choraś, 2014). Some layers of the former model can be
combines with some layers of the later model, this might help the users to decrease
the time as well as hard word dedicated in the entire process of transmission of
messages or data packets. These layers are combined for reducing the queuing of the

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process; the destination source does not need to wait for a long time in order to
receive the messages or data packets.
2. The layers of OSI model and layers of TCP/IP protocol correlate in various ways, the
functions in first 3 layers of OSI model are related with the TCP/IP model’s
application layer (Balachandran, Aggarwal & Halepovic, 2014). The function of the
transport and network layer of the OSI model relates to the internet and transport layer
of the TCP/IP model. The data link and physical layer of OSI model is combined to
form a network interface layer of the TCP/IP model.
3. The application layer is considered as the support layer and the physical. Network and
data link layers are the user support layers of the TCP/IP model. The support layers
are very vital for the model to work efficiently and the user support layers are very
important for the model to carry out transmission between the host network and the
destination network (Edwards& Bramante, 2015). The application layer contains
confidential as well as most important data regarding the working principles and
functions performed by the models, the user support layers are the ones that help the
models to make the users understand their working principles and the functions that
would be helpful for the users.
4. In OSI model, every layer asks for specific services from the next lower layer, the
lower layer is held responsible for encapsulating the information of higher layer
between specific headers. In the TCP/IP model, during the travelling of packet
through TCP/IP protocol stack, every layers’ protocols add or removed various fields
from the header. When a specific protocol adds up data on the header of the packet,
encapsulation is performed.
5. Data link layer makes sure that the packets of data have been passed on without any
error. It also ensures that proper physical protocol is allocated to data. The main