Protocol Use at each of the TCP/IP Model Layers

At each layer of the TCP/IP Model there are associated protocols that are in use. These too loosely map to the same ones that are found as part of the OSI Model.
At the Application layer you can find many but some of the more common ones include:

• BOOTP - Bootstrap Protocol
• DHCP - Dynamic Host Configuration Protocol
• DNS - Domain Name System (Service) Protocol
• FTP - File Transfer Protocol
• HTTP - HyperText Transfer Protocol
• IMAP - IMAP4, Internet Message Access Protocol (version 4)
• IRCP - Internet Relay Chat Protocol
• LDAP - Lightweight Directory Access Protocol
• LPD - Line Printer Daemon Protocol
• MIME (S-MIME) - Multipurpose Internet Mail Extensions and Secure MIME
• NFS - Network File System
• NIS - Network Information Service
• NNTP - Network News Transfer Protocol
• NTP - Network Time Protocol
• POP - POP3, Post Office Protocol (version 3)
• RDP - Remote Desktop Protocol
• RPC - Remote Procedure Call
• SMB - Server Message Block
• SMTP - Simple Mail Transfer Protocol
• SNMP - Simple Network Management Protocol
• SNTP - Simple Network Time Protocol
• SSH - Secure Shell
• TELNET - Terminal Emulation Protocol of TCP/IP
• TFTP - Trivial File Transfer Protocol
• X.400 - Message Handling Service Protocol
• X.500 - Directory Access Protocol (DAP)

At the Host to Host / Transport layer you can find these common protocols:

• ATP - AppleTalk Transaction Protocol
• FCP - Fiber Channel Protocol
• NBF - NetBIOS Frames protocol
• SPX - Sequenced Packet Exchange
• TCP - Transmission Control Protocol
• UDP - User Datagram Protocol
• At the Internet Layer you can find:
• IPv4 - Internet Protocol v4
• IPv6 - Internet Protocol v6
• ICMP - Internet Control Message Protocol
• IGMP - Internet Group Management Protocol
• IPSec - Internet Protocol Security

At the final layer of the TCP/IP Model, the Network Interface Layer, you can find:

• Ethernet
• Token Ring
• FDDI - Fiber Distributed Data Interface
• X.25
• Frame Relay
• RS-232
• v.35

These are not fully comprehensive lists but are examples of the more common protocols that are functioning at these different levels of the TCP/IP Model
In this article we reviewed the tie in of the TCP/IP / DOD Model to the CCNA and Network+ exams as well as took a look at the breakdown of the Four Layers of the TCP/IP Model
We wrapped up with a quick look at some of the protocols that are in use at each of the TCP/IP Model Layers
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