What is OSI Layer 7? Here's the explanation

 We certainly recognize that OSI (Open Systems Interconnection) is the reference model for how applications talk over a network. Instead a reference model is a conceptual framework for understanding relationships. The purpose of the OSI reference model is to guide vendors and developers so that their digital communications products and software programs work, and to facilitate a clear framework that describes the functions of a telecommunications network or system. Then What Is OSI Layer 7?

What is OSI Model

OSI (Open Systems Interconnection) is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system regardless of the underlying structure and internal technology. The goal is interoperability, namely to make a system able to interact and function with other communication systems using standard protocols.

Whereas the OSI model is a tool used by IT professionals to actually model or track the actual flow of how data transfers in a network. So, basically, the OSI model is a logical model/representation of how networked systems are supposed to send data (or, communicate) with each other.

History of the OSI Model

The International Standards Organization (ISO) developed the Open Systems Interconnection (OSI) model. Conceived in the 1970s when computer networking was just coming out, two separate models were combined in 1983 and published in 1984 to create the OSI model that many are known today.

By dividing the network communication into seven layers. In this model, layers 1-4 are considered the lower layers, and most of them are concerned with moving data. Layers 5-7, called the upper layer, contain application level data. Networks operate on one basic principle which is to forward them. Each layer handles a very specific job, and then passes data to the next layer.

How the OSI Model Works

IT professionals use OSI to model or track how data is sent or received over a network. This model breaks data transmission through a series of seven layers, each of which is responsible for performing specific tasks regarding sending and receiving data. The main concept of OSI is that the process of communication between two endpoints in a network can be divided into seven layers of different functions.

In the OSI layer architecture, each layer serves the layer above it and is partially served by the layer below it. So in messages given between users, there will be a flow of data down through the layers on the source computer, across the network and then up through the layers on the receiving computer.

It's just that the application layer at the top of the stack doesn't provide services to the higher level layers. The seven layers of functionality are provided by a combination of applications, operating systems, network card device drivers and network hardware that allows the system to transmit signals over Ethernet networks or via Wi-Fi and other wireless protocols.

Advantages of the OSI Model

1. The OSI model creates a common platform for software developers and hardware manufacturers that drives the creation of network products that can communicate with each other over a network.

2. It can help network administrators by dividing large data exchange processes into smaller parts.

3. Due to layer independence, the OSI model can prevent changes in one layer from affecting other layers.

4. Standardization of network components allows the development of multiple vendors.

5. Having excellent structure and special functions for each layer.

6. Can reduce complexity and accelerate evolution

Functions Of The 7 OSI Layers

As we know before, the OSI Model consists of seven layers or layers. By starting from the physical layer where the actual data transfer occurs with the use of a transmission medium. Down to the application layer which is the closest layer to the end user.

7. Application Layer

Layer 7 describes the specifications for the scope in which network applications communicate with network services. Provides services to user applications. This layer is responsible for exchanging information between computer programs, such as e-mail programs, and other services running on the network, such as printer servers or other computer applications. Serves as an interface with applications with network functionality, manages how applications can access the network, and then generates error messages. The protocols that are in this layer are HTTP, FTP, SMTP, DNS, TELNET, NFS and POP3.

6. Presentation Layer

This 6th layer functions to translate data that the application wants to transmit into a format that can be transmitted over the network. Protocols within this level are redirector software, such as Workstation services (in Windows NT) as well as Network shells (such as Virtual Network Computing (VNC) or Remote Desktop Protocol (RDP)).

5. Session Layer

This 5th layer serves to define how connections can be made, maintained, or destroyed. In addition, this layer also performs name resolution. The protocols that are in this layer are RPC (Remote Procedure Call), and DSP (AppleTalk Data Stream Protocol).

4.Transport Layer

This 4th layer functions to break data into data packets and provide serial numbers to these packets so that they can be rearranged on the destination side after being received. In addition, this layer also makes a sign that the packet is received successfully (acknowledgement), and retransmits packets that are lost in the middle of the road. The protocols that are in this layer are UDP, TCP, and SPX (Sequence Packet Exchange).

3.Network Layer

This 3rd layer functions to define IP addresses, create headers for packets, and then do routing through internetworking using routers and layer-3 switches. The protocols that are in this layer are DDP (Delivery Datagram Protocol), Net BEUI, ARP, and RARP (Reverse ARP).

2. Data-link Layer

This 2nd layer functions to determine how data bits are grouped into a format known as a frame. In addition, at this layer there are processes of error correction, flow control, hardware addressing (such as Media Access Control Address (MAC Address), and determining how network devices such as hubs, repeaters, and switches. IEEE 802 specification, divides the layer This layer is divided into two child layers, namely the Logical Link Control (LLC) layer and the Media Access Control (MAC) layer.

1.Physical Layer

This 1st layer serves to define network transmission media, signaling methods, bit synchronization, network architecture (such as Ethernet or Token Ring), network topology and cabling. In addition, this layer also defines how the Network Interface Card (NIC) can interact with cable or radio media. The protocols that are in this layer are Ethernet, FDDI (Fiber Distributed Data Interface), ISDI, and ATM.

Conclusion

So What Is OSI Layer 7? In simple terms, to explain what OSI Layer 7 is, it describes how information from an application software on a computer moves across a network media to an application software on another computer by dividing it into 7 layers where each layer has a specific network function.

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Resa Risyan

Just an ordinary person who wants to share a little knowledge, hopefully the knowledge I provide can be useful for all of us. Keep in mind! Useful knowledge is an investment in the afterlife.