HTML
OSI Model Layers - HTML
The OSI Reference Model (Open Systems Interconnection Reference Model) is a 7-layer reference model for computer network communication defined by ISO/IEC 7498-1, originally established by the International Organization for Standardization (ISO) in 1984 and revised in 1994. It provides a common framework for ensuring interoperability between different systems, defining communication protocols across seven hierarchical layers from the Physical Layer to the Application Layer. It is widely used as a foundation for network design, troubleshooting, and education.
OSI Model
ISO Standard
Networking
Protocol
Communication Model
ISO/IEC 7498-1
<table>
<thead><tr><th>code</th><th>slug</th><th>name</th><th>description</th><th>dataUnit</th><th>keyProtocols</th></tr></thead>
<tbody><tr><td>7</td><td>application-layer</td><td>Application Layer</td><td>The layer that provides network services to end-user applications.</td><td>Data</td><td>["HTTP","HTTPS","FTP","SMTP","POP3","IMAP","DNS","SNMP","Telnet","SSH"]</td></tr>
<tr><td>6</td><td>presentation-layer</td><td>Presentation Layer</td><td>The layer that translates data between the application layer and the network.</td><td>Data</td><td>["SSL","TLS","JPEG","GIF","MPEG","ASCII","EBCDIC","MIME"]</td></tr>
<tr><td>5</td><td>session-layer</td><td>Session Layer</td><td>The layer that establishes, manages, and terminates sessions between applications.</td><td>Data</td><td>["NetBIOS","RPC","PPTP","SIP","SAP"]</td></tr>
<tr><td>4</td><td>transport-layer</td><td>Transport Layer</td><td>The layer that provides end-to-end communication and error recovery.</td><td>Segments</td><td>["TCP","UDP","SCTP","DCCP","SPX"]</td></tr>
<tr><td>3</td><td>network-layer</td><td>Network Layer</td><td>The layer that handles data routing, forwarding, and addressing.</td><td>Packets</td><td>["IP","IPv4","IPv6","ICMP","IGMP","OSPF","BGP","RIP","IPsec"]</td></tr>
<tr><td>2</td><td>data-link-layer</td><td>Data Link Layer</td><td>The layer that provides reliable data transmission across a single network segment.</td><td>Frames</td><td>["Ethernet","Wi-Fi","PPP","HDLC","ATM","Frame Relay","ARP","L2TP"]</td></tr>
<tr><td>1</td><td>physical-layer</td><td>Physical Layer</td><td>The layer that transmits raw bit streams over a physical medium.</td><td>Bits</td><td>["Ethernet Cable","Fiber Optic","Coaxial Cable","Twisted Pair","USB","Bluetooth","RS-232"]</td></tr></tbody>
</table>