What is the OSI Protocol?
All data travelling from a computer to a printing device, or from e.g. a printing device to the JetAdvice Cloud, uses the OSI Protocol.
In short, all data must travel through different layers to get from one device to another. That is the OSI Protocol.
The OSI Protocol is a very old standard. In 1977, the first OSI Protocol was developed, designed, and released by the International Organization of Standardization (ISO).
The OSI protocol consists of a total of seven layers – from the physical hardware layer to the software application layer. Data and information are received by each layer from an upper layer.
Facts about the OSI Protocol
The OSI protocol consists of a total of seven layers:
Layer 1, the Physical Layer
The first layer is the connecting hardware, such as Ethernet, cables, optical fiber, coaxial cable, and even wireless.
Layer 2, the Data Link Layer
The main purpose of the second layer is to locate any errors by adding headers to data packets.
Layer 3, the Network Layer
The third layer transfers data from nodes to nodes. Routers and switches are the devices used for this layer. They connect the nodes in the network to transmit and control data flow.
The Network Layer assists the following protocols: Internet Protocol (IPv4), Internet Protocol (IPv6), IPX, AppleTalk, ICMP, IPSec and IGMP.
Layer 4, the Transport Layer
The Transport Layer works on two determined communication modes: Connection-oriented and connectionless. This layer transmits data from source to destination node. It uses the most important protocols of the OSI Protocol family which are: Transmission Control Protocol (TCP), UDP, SPX, DCCP and SCTP.
Layer 5, the Session Layer
The Session Layer creates a session between the source and the destination nodes and terminates sessions on completion of the communication process. The protocols used are: PPTP, SAP, L2TP and NetBIOS.
Layer 6, the Presentation Layer
The functions of encryption and decryption are defined on this layer. It ensures that data is transferred in standardized formats by converting data formats into a format readable by the application layer. The following are the presentation layer protocols: XDR, TLS, SSL and MIME.
Layer 7, the Application Layer
This layer works at the user end to interact with user applications. QoS (quality of service), file transfer and email are the major popular services of the application layer. This layer uses following protocols: HTTP, SMTP, DHCP, FTP, Telnet, SNMP and SMPP.
The short OSI Protocol introduction above was inspired by this very informative text on techopedia.com.