Layered Security, is a standard that regulates hardware and software solutions used in networking. The OSI model has removed its dependency. Layered Security, Open Systems Interconnection (OSI) model was developed by the ISO (International Organization for Standardization). This model defines how applications running on network-aware devices will communicate with each other. And it provides correct manageability. The OSI model is a standard divided into 7 layers. The task of each layer is to serve the higher layer. During data transmission, the layers take turns working. OSI layers have an orderly structure that follows each other in order and they work in an integrated manner.
Layered Security Research
Layered Security data passing through the application, presentation, and session layers are divided into sections (segments) in the data transport layer. In the network layer, address information is added to the sections and becomes a package. In the data transmission layer, the receiver’s MAC address information is added to the packets, and a structure called frame is created. At the physical layer, data is transmitted in bit-size to the physical layer of the receiving network. OSI layers are described in titles below;
- Application Layer: Application layers are programs that will use the network. Email, browser, and web browser software used by the user are included in this layer. OSI layers are at the top of the application layer.
- Presentation Layer: The presentation layer is the layer where the formal arrangements of the data are made. While transmitting data to the application layer, coding, and transformation processes are performed on the data. Encryption of data, decoding, compression, expansion of encrypted data takes place in this layer.
- Session Layer: The session layer is the layer where the connection between the computers to be communicated, used, and terminated. Session layer ensures data security and retransmission of data if there is a problem in data transmission. Protocols such as NFS, Net BIOS, Sockets, and SQL operate on this layer.
- Transport Layer: The transport layer is the layer in which the data will be transmitted. In the transport layer, the protocols that the data will be transmitted from end to end are determined. TCP, SPX, and UDP protocols work at the transport layer.
- Network Layer: The network layer is the layer in which the most efficient physical path for data transmission is determined. Logical and physical addressing and address resolution operations are also performed on this layer. Routers and IP protocol are in this layer.
- Data Link Layer: It is the data transmission layer that determines the access authorizations and rules of the physical layer in order to perform error-free data transfer from one node to another. The frame structure is created by adding error control bits to the packets coming from the network layer. Ethernet and Token Ring access methods work on this layer.
- Physical Layer: The physical layer is the layer where it is determined how the data bits are transmitted to the receiver. It defines how ones and zeros are converted and transmitted into electrical, light or radio signals. On the sending side, the physical data bits (0-1) are converted into electrical signals and placed on the cable, while the physical layer on the receiving side converts these signals read from the cable into data bits. The hub is located in the physical layer.