Derived from ISO/IEC 7498-1

OSI Seven-Layer Reference Model

The seven OSI layers with what each does and the protocols that live there, as one downloadable reference figure.

All templates

OSI seven layer model: the ISO/IEC 7498-1 reference stack

The seven layers of the OSI Basic Reference Model stacked from layer 7 Application at the top to layer 1 Physical at the bottom, each with its number, official name, core function and canonical protocol examples.

Read the stack top down to follow data leaving an application, and bottom up to follow it arriving. Layers 7 to 4 are the host layers that live in end systems; layers 3 to 1 are the media layers that move bits between them. ISO/IEC 7498-1:1994 defines the model.

OSI seven layer model: the ISO/IEC 7498-1 reference stack The seven layers of the Open Systems Interconnection Basic Reference Model from ISO/IEC 7498-1:1994, published jointly by ISO and IEC. The bands stack from layer 7 Application at the top, through Presentation, Session, Transport, Network and Data Link, to layer 1 Physical at the bottom. Each band lists the layer number, official name, core function, protocol data unit and example protocols. Side labels mark layers 7 to 4 as the host layers and layers 3 to 1 as the media layers. 7 Application User-facing protocols and APIs HTTP, SMTP, FTP, DNS Unit: Data 6 Presentation Encoding, encryption and compression TLS, JPEG, ASCII, Unicode Unit: Data 5 Session Establish and maintain conversations NetBIOS, RPC, SMB Unit: Data 4 Transport End-to-end delivery and reliability TCP, UDP, QUIC Unit: Segment 3 Network Routing across interconnected networks IP, ICMP, OSPF, BGP Unit: Packet 2 Data Link Frame delivery on the local segment Ethernet, PPP, ARP Unit: Frame 1 Physical Bits on the wire or radio Cable, Fibre, Wi-Fi PHY Unit: Bit HOST LAYERS Layers 7 to 4 MEDIA LAYERS Layers 3 to 1 Source: ISO/IEC 7498-1:1994, OSI Basic Reference Model

When a conversation needs the layers named precisely, from physical media to application.

What you need and what you get

You'll get

  • The reference model figure, downloadable as PNG or PowerPoint

Derived from ISO/IEC 7498-1:1994, OSI Basic Reference Model. ISO. All rights reserved by the publisher.