The OSI Model's Data Flow in Seven layers
The seven layers of the OSI model are traversed as data is sent between devices. Data first descends seven levels from the sender's end and then ascends seven levels back on the receiver's end. The procedure by which data moves across the OSI model is as follows these layers:
- Application Layer
- Presentation Layer
- Session Layer
- Transport Layer
- Network Layer
- Data-Link Layer
- Physical Layer
1. Application Layer
The only layer that works directly with user data is Application Layer. Email clients and web browsers are examples of software applications that depend on the application layer to start conversations. Application layer protocols include the Simple Mail Transfer Protocol (SMTP), which is one of the protocols that allows email correspondence, and HTTP.
2. Presentation Layer
The Presentation layer, makes the data presentable for applications to use, is mostly in charge of preparing the data for use by the Application layer. Data translation, encryption, and compression are handled by the presentation layer.
Two means of communication Since several encoding techniques may be used when communicating, the Presentation layer's job is to convert incoming data into a syntax that the receiving device's application layer can comprehend.
3. Session Layer
This layer is in charge of initiating and terminating communication between the two gadgets. The term "session" refers to the interval of time between the start and end of a communication. In order to prevent resource waste, the session layer makes sure the session remains open for the entire amount of data being transferred before quickly ending it.
4. Transport Layer
The two devices' end-to-end communication is handled by the transport layer. This involves dividing data into pieces and transferring it from the session layer to the network layer. Reassembling the segments into data that the session layer can use is the responsibility of the receiving device's transport layer.
User Datagram Protocol (UDP) and Transmission Control Protocol (TCP) are examples of transport layer protocols.
5. Network Layer
Data transfer between two distinct networks is made possible by the network layer. The network layer is not required if the two devices communicating are connected to the same network. On the sender's device, the network layer disassembles segments from the transport layer into smaller pieces known as packets, which are then reassembled on the receiving device.
IP, the Internet Control Message Protocol (ICMP), the Internet Group Message Protocol (IGMP), and the IPsec suite are examples of network layer protocols.
6. Data-Link Layer
With the exception of facilitating data transfer between two devices on the same network, the data link layer and the network layer are extremely similar. Packets from the network layer are divided into smaller units called frames by the data link layer. In intra-network communication, the data link layer is also in charge of flow control and error control, just like the network layer.
7. Physical Layer
The actual hardware used in data transfer, such as switches and cables, is included in this layer. This layer is also where the data is transformed from a string of 1s and 0s into a bit stream. For the 1s and 0s on both devices to be distinguishable from one another, a signal convention must also be agreed upon by their physical layers.
