Support Ukrain
Adaltas logoAdaltasAdaltas logoAdaltas

IT Network

An IT network is a group of interconnected electronic systems.

To share information between systems, the OSI model defines and standardizes the communication functionalities and their interactions. The standard defines a model composed of 7 layers :

  • Physical(1): The physical layer is the lowest layer. This layer manages the physical connections, maintains them and transmitting bits over them.

  • Data Link(2): The task of the data link layer is to ensure reliable transmission of the data and to control access to the transmission medium. The data link layer is divided into two sub-layers: LLC (Logical Link Control, layer 2b) that handle the routing for the IP or IPX protocol and the MAC (Media Access Control, layer 2a) that handle the routing for the physical systems with their MAC address.

  • Network(3): The network layer is responsible for transmitting the data packets to the destination. Data transmission takes place across the entire communications network and includes routing between the network nodes. If a direct connection to the destination is not possible, the packets must be forwarded by nodes located along the way.

  • Transport(4): The tasks of the transport layer are the segmentation of the data stream, congestion avoidance and ensuring error-free transmission. The data is segmented into chunks called frames and the address (port) of the target service is added. Additional metadata is added for verification and control of the frames. The transport layer provides uniform access to the application-oriented layers 5 to 7, so that they do not need to consider the properties of the communication network.

  • Session(5): The session layer is responsible for process communication between two systems. This layer open, close and manage instances of communication channels called sessions. This layer provides authentication, authorization and session restoration services.

  • Presentation(6): The presentation layer ensures that data sent by the application layer of one system can be read by the application layer of another system. If necessary, the presentation layer acts as a translator between different data formats by using a data format that both systems can understand, like the ASN.1 (Abstract Syntax Notation One). This layer also provides data compression and encryption services.

  • Application(7): The application layer manage services, applications and their access to the network. It allows applications to connect to the lower layers. The applications themselves do not belong to the layer.

Related tags
DNS

Related articles

Bridging the DBnomics Swagger/OpenAPI schema with GraphQL

Bridging the DBnomics Swagger/OpenAPI schema with GraphQL

Categories: DevOps & SRE, Front End | Tags: Data Engineering, JAMstack, REST, GraphQL, JavaScript, Node.js, Schema

While redacting a long and fastidious document today, I came across DBnomics, an open platform federating economic datasets. Browsing its website and APIs, I found their OpenAPI schema (aka Swagger…

David WORMS

By David WORMS

Apr 8, 2021

Canada - Morocco - France

International locations

10 rue de la Kasbah
2393 Rabbat
Canada

We are a team of Open Source enthusiasts doing consulting in Big Data, Cloud, DevOps, Data Engineering, Data Science…

We provide our customers with accurate insights on how to leverage technologies to convert their use cases to projects in production, how to reduce their costs and increase the time to market.

If you enjoy reading our publications and have an interest in what we do, contact us and we will be thrilled to cooperate with you.