OSI Overview

OSI Model Explained The Open Systems Interconnection Model describes how data is sent and received over a network. It is a way of describing how different applications and protocols interact with each other. The model is generic and applies to all network types. So, not only TCP/IP or Ethernet. This model is the foundation of networking and it will often be referred to in industry. It can be seen as a concept that splits up the communication into several ’layers’....

July 19, 2022 · 3 min · Me

Layer 7: Application Layer

Overview This layer directly interacts with data from the user. The application layer handles the protocols and data manipulation that the software relies on to present readable data. For example, HTTP and SMTP. The application layer is used by network applications. A network application might be a web browser, outlook skype etc. These applications are dependent on application layer protocols to function. The following protocols form the application layer: List of protocols @Mojca_Ciglaric...

July 19, 2022 · 2 min · Me

Layer 6: Presentation Layer

Overview This layer is responsible for the preparation of the data before it is presented. This means the data is translated, encrypted or compressed so that the receiving device understands the data. The presentation layer translates the data from previous layers. This data can be in different formats and so the presentation layer is the unifying layer that merges all formats into a standard format. For example, the presentation layer may receive bits showing up as ones and zeros....

July 19, 2022 · 2 min · Me

Layer 5: Session Layer

Overview This layer is responsible for opening and closing the communication, also called sessions. The session layer ensures sessions stay open long enough to transfer all communicated data. It also uses checkpoints, this ensures that a file download can be resumed even if the connection is lost halfway through. The session layer helps to setup and manage connections. It enables the sending and receiving and data which is followed by the terminations of sessions....

July 19, 2022 · 2 min · Me

Layer 4: Transport Layer

Overview This layer is responsible for the end-to-end communications between two decives. This layer also ensures flow and error control. This means it makes sure someone with a fast connection does not overwhelm the reciever and ensuring the data recieved is complete. In this layer the data of the session layer is divided into smaller pieces: segments. The transport layer controls the reliability of communications with segmentation, flow control and error control....

July 19, 2022 · 3 min · Me

Layer 3: Network Layer

Overview This layer handles the delivery of messages between different networks. This layer is unnecessary for communications within the same network. In this layer the segments from the transport layer are divided into smaller pieces called packets The network layer receives segments from the transport layer and performs the transmission of the received data segments from one computer to another located in different networks. The data units in the network layers are called packets....

July 19, 2022 · 2 min · Me

Layer 2: Datalink Layer

Overview This layer handles the delivery of messages between nodes on the same network. It moves data into and out of a physical link in a network. In this layer the packets from the network layer are divided into smaller pieces, frames. The data link layer receives packets from the network layer. Data packets contain IP addresses of the sender and receiver. There are two kinds of addressing: Logical Addressing - Network Layer Physical Addressing - Data Link Layer - Physical addressing is done at the data link layer where the MAC addresses of the sender and receiver are assigned to each data packet which are used to form a frame....

July 19, 2022 · 3 min · Me

Layer 1: Physical Layer

Overview This layer interacts with the actual hardware and signaling mechanism. It is in fact the only layer that deals with physical connectivity. The physical layer is all about converting binary data and converting it into electrical pulses, and vice-versa.

July 19, 2022 · 1 min · Me