welcome to the second section off or course section. Addressing the eyes OS I model the very famous seven layers this section is
explaining, demonstrating these seven layers and their functionalities.
The eyes always I model, as we can see, is an output off the ISA International Standardization Organization.
This outfit is named the OS I model Open System interconnection model.
It's a primary architectural model. Ford Networks. It was developed in 1983.
It's only a group off concepts. This means that the model does not specify a certain hardware or software to exist. It is a group of concepts. It's a conceptual model. Debt specifies the functionalities that that are needed to be done to transmit data
source to a certain destination over the Internet.
It specifies how data
can be sent or received. Either hope to help, which means I either from
the machine do this which do the router and so forth, step by step, or
sending and receiving data and to end, which means sending and receiving data between a source that is in Malaysia and a destination that is in Egypt,
which means that both are trying to send correct data
reliable data from a certain source on the Internet to a certain destination over the Internet Worldwide,
the benefits off dividing this model into layers are a lot.
Dividing the network communication process into layers allows for easier troubleshooting arouse for for easier
easier specifications for each layer Toby set inside this model.
It allows for multiple vendors to build their products either software or hardware products based on the same standard model that is called the O. S. I.
Many vendors. Giant companies can
establish hardware components or software components based on this eyes OS I model, and these components can interact and can send and receive data to each other. Since they are based on the same mother, the OS I model the Open System Interconnection model,
designed by the Aiso International Standardization Organization.
Various types of networks
with various types of hardware and software can communicate, which means, for example, that Windows machines can communicate with Lennox machines. IBM machines can't communicate with apple machines. Machines on copper cables can communicate with machines on fiber optic cables. All of these,
since based on the same model, can communicate with each other
and concerned and transmit data with each other. Built on the same
standard model that is the OS I model developed by the eyes.
The layer separation makes it easier to change the design off one layer without affecting the other layers without affecting the upper or the lower layer. The design, the functionality off each layer can be made better
can be change it without affecting the seven layers as a whole.
We just take into consideration what each layer can take from the upper and deliver. Tow the lower when changing the design off. This late
layers interact with each other while sending each layer passes. The data downwards from the seventh toa the first while receiving data is passed upwards from the first to the sudden death
and the headers off each layer is added while you are sending and it is removed while you are receiving. This is the interaction with the layers that allows, and that
gives us, at the end better communication between hosts and destinations over the Internet.
This is the diagram showing the seven layers we should know by heart these names and we shall know by heart that we are counting from bottom toe up.
The first layer is the physical. It's always later number one.
The second is the data link. The third is the network, the fourth is the transport, the fifth, The fifth is the session. The six is the presentation and the seventh is the application layer.
We always count from down to up
if summarized in one sentence. In this light,
the application is responsible for communication between the application itself as a software and the network processes lying in the layers down.
The presentation is responsible off data representation.
The session is responsible for managing the session in the inter host communication process, starting
ending and managing the session. Wild communication. The transport is responsible off and toe and connections either reliable or best effort delivery.
The network is responsible for addressing and routing, finding the best path for the data to go through. Based on the address off each machine, the datalink is responsible for accessing the media and avoiding collisions.
The physical is responsible for the binary transmission off ones and zeros
representing the data in electrical form or in light. For if we are going to use the fiber optic cables,
natural protocols that were based upon the eyes. Always I model are a lot, but we are here focusing on four protocols that were used and we're comin
and were extensively known.
Protocols Based on the eyes Always I model the Net Berry Protocol the I p X SP experts call the apple toe protocol and we end by the TCP I people to cool the standard protocol off the Internet that will be address the next section in dictates.
They're not very protocol. Not very stands for net bars. Extended user interface. It was a land protocol that work only overland and do not work over a wide area networks.
It has limited performance, not a good performance, and it's now almost obsolete protocols.
It does not exist a lot or not common to be existing over the world.
But this was a lamb protocol based on the eyes always, Simon.
The second protocol is the I p x spx. That was vendor oriented that was designed by one off the company's working in hardware and software.
It will standard based on the eyes O S I. And it's supported
transmission of data over when
But it also had a disadvantage it row back that it was
or rented too much towards its thunder.
It had poor performance if used with other vendors. If you use this protocol with another vendor, not with the vendor that made this protocol and designed it, you will have a very poor performance or you're on your network and your machines.
Apple talk is a standard protocol based on the eyes OS I. It supports when, and it supports
data transmission over routers, but it is very
oriented towards its vendors, and it also has the same grow back and the same this advantage off poor performance if used with other vendors. It worked greatly with the same vendors that made this protocol and made the machines using it. But it had a very
poor performance. If you change it, the machines
Toby made with other vendor using this protocol
the TCP i p, the worthless C P I. P. Stands for transmission control protocol, Internet protocol. It's a standard protocol. It supports when and supports Toby
track transmitting data over rotors.
It is not vendor oriented, and this is a very big advantage in T c p I P. That makes it growing and developed and always the standard protocol for transmission over the Internet. Nowadays, the D C. P i. P is the most widely used protocol over the Internet. The TCP I p
is completely and entirely mapped. Tow the OS Eilers, The OS ie seven layers
to the TCP I p protocols. As you can see in this diagram,
it is not a one toe one mapping. It's a group toe one mapping between the OS I'll ears and the TCP I P. Protocol.
Now, we had a good idea about the eyes. Always. I model in this lecture. Thank you.