Network protocols are different from each other depending on the characteristics assigned to them by their developer or manufacturer. The question would be how do these programmers manage to design a network that can connect and exchange blocks of data with others? The answer is easy: “because they comply with the OSI layer model” .
In this article we will explain how the standards established by the International Organization for Standardization (ISO) ensure greater compatibility and improve the operation between different types of network technology.
We will show you how information travels from an application’s programs , through a network medium, to other programs located on different computers on the network regardless of their geographical area.
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What is the OSI layer model for computer network protocols ?
The OSI model, for its acronym “Open System Interconnection” , are standards that were created for open systems. These universal standards or standards were launched by the International Organization for Standardization, ISO (in English “International Organization for Standardization” ).
The model studies the protocols that open networks must comply with so that there can be reliable interconnections between those networks, especially those created by different technology developers. That is, for one network to be identified by another, they must meet the standardized parameters of the OSI layer model.
But before moving forward we will have to know some data that is necessary to be able to definitively understand what these standards are for network protocols.
Origin
Between the 60s and 70s the networks with monolithic architecture began to have a very important growth, as companies realized the advantages offered by technology in the management of their data.
This began to generate a significant problem , the technologies of the different companies could not communicate with each other, since their protocols with which they were developed were not the same, generating incompatibility between them .
Many companies solved this problem by designing a third network that could read the protocols of both original networks, but it also did not solve the problem definitively because that network was also incompatible with other open networks of other manufacturers.
These problems became increasingly large and many companies began to pressure the US government to start taking action on the matter.
History
It was only in 1984 when the OSI model finally emerged, which had its acceptance in the ISO standards with the number ISO / IEC 7498-1 , which He attributed 7 levels to comply with the OSI model.
It establishes the universal rules or language that every network protocol must have so that it can be considered as such, thus guaranteeing affinity with other networks .
Evolution
After the acceptance time of the OSI model, more flexible protocols began to exist , since the model itself is not so exactly true in reality and the layers they are not as different as the model indicates.
Although it is a model that serves perfectly for the teaching of networks , it is also one that manufacturers are more inclined to when developing their network protocols, without being entirely accurate as your model indicates.
What are the advantages of devising a computer network with the model of the ISO?
Among the advantages proposed by devising a computer network with the ISO model we can name the following:
- The OSI reference model can be used to establish a framework that can facilitate understanding of how information travels in a network .
- Allows visualize how data packets or Blockchain travel from application programs through a specific network medium and reach another program, located on another computer also on the same network, even when the issuer and the that receives that information have different types of network media.
- It allows to divide the existing communication in the network into simpler parts and small.
- Normalize the different hardware and software of a network so that they can communicate with each other.
- Standardize the components of a network allowing the development and support of different products offered by manufacturers.
What are the layers of the model and what is its function within the network?
As we said before, the OSI model sets standards for universal communication between different network protocols, analyzing how data blocks travel through the network helping to understand the action that occurs between communication from one computer to another .
For this, the model has divided the work into 7 different levels or layers, each of them has a specific mission.
We will show you each one from the highest to the lowest:
Application
The application layer is the closest to the user , features that do not provide services to any other OSI layer, but only serve to provide network services to applications that have the user.
An example of this would be an Excel spreadsheet or Internet browsers.
Presentation
It is the layer that is dedicated to the representation of data , that is to say, it guarantees that the information that the layer number 7 emitted, that of the application, is read.
This layer is dedicated to translate between several established formats the data used in a common format so that it can be understood by the receiver allowing compressing and encrypting the data.
Session
When two hosts are communicating , this layer is the one dedicated to establishing manage and end the session between them . The objective of the layer is to offer different provisions so that data transfer and classes of services are efficient.
Transportation
The Transport layer is dedicated to end-to-end connections , that is, it transports the data trying to isolate the upper layers from the implementation details. This layer establishes, contains and properly terminates all virtual circuits providing a reliable service
Red
The so-called network layer is that it provides connectivity and selects the route between two host systems , regardless of whether they are located on geographically distinct networks.
This layer is where the routers are located, whose mission is to route the functions, fragment the data and then rearm them.
This layer is divided into three parts:
- Access
- Convergence
- Convergence independent
Data link
The OSI Data Link layer, is intended to provide reliable transit through physical links . That is, it deals with physical addressing the access that the network may have, its topology and flow control.
It is divided into:
- Sublayer of logical link control (LLC) , defines how data blocks will be transmitted.
- Sublayer of access control to the medium (MAC) , its mission is to act as a controller of the network adapter, that is, the underlying hardware.
Physics
The first layer defines all those technical specifications, whether mechanical, electrical, functional, to activate or deactivate a physical link between end systems , among other functions.
It is also dedicated to everything related to voltage, changes for the timing of the voltages, speed that the physical data will have, physical connectors and any other attribute that is defined as a physical specification.
List of the main protocols that work between the 7 layers of the OSI model
There are different protocols that work as a set of rules and procedures between two or more computers that belong to a network, and since we deal with the analysis of the OSI model, we want to show you the most important ones that you can find in that model.
Next, we detail them:
IP
From English “Internet Protocol” , the data is sent by the network through blocks that we call packages or datagrams and differ in size. It belongs to the “Network” layer of the OSI model.
This protocol does not guarantee whether or not a datagram reaches its destination correctly, since they can arrive duplicated, broken, or in a different order from the one they left or simply do not arrive.
TCP
The transmission control protocol named after “Transmission Control Protocol” , is one of the most used protocols on the Internet.
It is responsible for managing the flow of data that comes from the lower layer of the OSI model or goes to that layer. Its mission is that two computers that are connected to the network can control the emission of data.
This protocol belongs to the “Transport” layer of the OSI model.
NetBIOS
The network protocol created to provide services such as:
- Name service , which records the name of the computers, applications and any other instrument that can be identified and that is connected to the network.
- Packet services , facilitates the sending and reception of data packets from a network.
- Session service , is similar to the TCP protocol, this allows generate the establishment of connections between two or more points belonging to a network.
The NetBIOS protocol belongs to the “Session” layer of the model.
Wi-Fi h3>
Wireless Fidelity is a set of standards for wireless networks which are based on IEEE 802.11 specifications. It is also used for Internet access.
This protocol belongs to the “Data link” stage .
HTTP
This protocol used for Internet access belongs to the “Application” stage of the OSI model. They are logical links which are responsible for processing and responding to all requests we make in order to view a web page.