OSI Layer	Data Types	Protocols	Description
Application	Message	FTP, HTTP, SNMP, SMTP, Telnet	Software implementation, user interface
Presentation	Packets		Formats Data, Encryption/Decryption, Compression/Decompression
Session	Packets		Session Control, Handshaking
Transport	Segments	TCP, SPX, UDP, NWLink, DNS, NetBIOS/BEUI	Flow Control, Sequencing, Transmission Control, Error Correction/Recovery, Name Resolution to Logical Address
Network	Datagrams	IP, IPX, NWLink, NetBIOS/BEUI, ARP, OSPF, RIP, DLC, ICMP, AppleTalk	Logical Addressing (Net Address ↔ MAC Address), Routing and Priority of Service
Data Link	Frames	ODI/NDIS, SLIP, PPP	Identifies Network Layer Protocols and encapsulates them [LLC], Assign Physical Address, CRC Error Detection (not correction) [MAC], NIC drivers
Physical	Bits		Puts data on or takes data off the pipe, Manchester encoding, physical hardware/cabling

OSI Model Quick Reference

To remember the OSI Layers, think…

APpS Transport Network Data Physically

To remember the Data Types, think…

Mud Packs Prevent Skin Damage, Facial Blemishes

OSI Layers Quick Reference

David D. Scribner

2001-04-28T00:19:00

David Scribner