Application is the layer that handles the end user interaction with the internet. For example HTTPS (Hypertext Transfer Protocol Secure) which is used by the web browsers, or DNS (Domain Name System) which creates human readable network names such as “www.google.com” instead of something like 192.168.1.1. 

--> Examples of Application Layer Protocols

TELNET, TELetype NETwork 🔵 FTP, File Transfer Protocol 🔵 TFTP, Trivial File Transfer Protocol 🔵 NFS, Network File System 🔵 SMTP, Simple Mail Transfer Protocol 🔵 LPD, Line Printer Daemon 🔵 X window 🔵 SNMP, Simple Network Management Protocol 🔵 DNS, Domain Name System 🔵 DHCP, Dynamic Host Configuration Protocol 🔵 HTTP, Hypertext Transfer Protocol /HTTPS, Hypertext Transfer Protocol Secure 🔵 POP, Post Office Protocol  🔵 IRC, Internet Relay Chat 🔵 MIME,  Multipurpose Internet Mail Extension

Sitting below the application layer, the transport layer ensures reliable data transfer between devices,. It manages data segmentation, reassembly, error checking, and flow control. Protocols like TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) operate at this layer. 

--> Examples of Application Layer Protocols

ATP, AppleTalk Transaction Protocol 🔵 CUDP, Cyclic UDP  🔵 DCCP, Datagram Congestion Control Protocol  🔵 FCP, Fibre Channel Protocol 🔵 IL, IL Protocol 🔵 MPTCP, Multipath TCP 🔵 NORM, NACK-Oriented Reliable Multicast 🔵 RDP, Reliable Data Protocol 🔵 RUDP, Reliable User Datagram Protocol 🔵 SCTP, Stream Control Transmission Protocol 🔵 SPX, Sequenced Packet Exchange 🔵 SST, Structured Stream Transport 🔵 TCP, Transmission Control Protocol 🔵 UDP, User Datagram Protocol 🔵 UDP-Lite 🔵 µTP, Micro Transport Protocol

The network layer focuses on routing data packets across networks. It deals with addressing and logical network topology. IP (Internet Protocol) is a key protocol at this layer, responsible for assigning unique IP addresses to devices and forwarding data packets based on these addresses. 

--> Examples of Network Layer Protocols

ARP,  Address Resolution Protocol 🔵 ICMP,  Internet Control Message Protocol 🔵 IPv4, Internet Protocol Version 4 🔵 IPv6, Internet Protocol Version 6

The link layer is the lowest layer and deals with physical connections and local network communications. It manages the physical addressing of devices on a network (like MAC addresses) and handles error detection and correction at the hardware level 

-- > Examples of Data Link Layer Protocols

SDLC, Synchronous Data Link Protocol  🔵 HDLC,  High-Level Data Link Protocol🔵 SLIP, Serial Line Interface Protocol 🔵 PPP, Point to Point Protocol 🔵 LCP, Link Control Protocol 🔵 LAP, Link Access Procedure  🔵 NCP, Network Control Protocol