This post lists common network protocols, their full names, and the OSI layers to which they are commonly assigned.
Some protocols span multiple layers or may be classified differently depending on the networking model. The tables below use their most common OSI classifications.
Layer 7: Application
Abbreviation
Full Name
Layer
HTTP
Hypertext Transfer Protocol
Application
HTTPS
Hypertext Transfer Protocol Secure
Application
FTP
File Transfer Protocol
Application
FTPS
File Transfer Protocol Secure
Application
SFTP
SSH File Transfer Protocol
Application
TFTP
Trivial File Transfer Protocol
Application
SMTP
Simple Mail Transfer Protocol
Application
POP3
Post Office Protocol Version 3
Application
IMAP
Internet Message Access Protocol
Application
DNS
Domain Name System
Application
DHCP
Dynamic Host Configuration Protocol
Application
SSH
Secure Shell
Application
Telnet
Teletype Network Protocol
Application
SNMP
Simple Network Management Protocol
Application
NTP
Network Time Protocol
Application
LDAP
Lightweight Directory Access Protocol
Application
LDAPS
Lightweight Directory Access Protocol Secure
Application
SIP
Session Initiation Protocol
Application
RTP
Real-time Transport Protocol
Application
RTCP
Real-time Transport Control Protocol
Application
RTSP
Real-Time Streaming Protocol
Application
MQTT
Message Queuing Telemetry Transport
Application
AMQP
Advanced Message Queuing Protocol
Application
CoAP
Constrained Application Protocol
Application
WebSocket
WebSocket Protocol
Application
SMB
Server Message Block
Application
NFS
Network File System
Application
RDP
Remote Desktop Protocol
Application
IRC
Internet Relay Chat
Application
XMPP
Extensible Messaging and Presence Protocol
Application
NNTP
Network News Transfer Protocol
Application
Syslog
System Logging Protocol
Application
WHOIS
Whois Protocol
Application
RADIUS
Remote Authentication Dial-In User Service
Application
TACACS+
Terminal Access Controller Access-Control System Plus
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