Note:
Each layer builds on any one of the layers underneath it (exception: A Gateway isn't a layer).
The protocol the application sees and uses.
| HTTP |
HyperText Transport Protocol, for web browsers and HTML pages. |
| NFS |
Network File System, for accessing disk drives across the network. |
| NNTP |
Network News Transport Protocol, for USENET newsgroups. |
| SMTP, POP, IMAP |
Mail protocols: Simple Mail Transport Protocol handles the deliveries. Post Office Protocol uses it to drop off messages. Internet Mail Access Protocol uses it, saving messages on the server. |
| FTP, TFTP, FSP |
File Transfer Protocol (uses TCP), and cousins: Trivial FTP
(uses UDP for small boot files), File Service Protocol (lets you restart after an interruption) |
Breaking up of data into packets (packages of data). Collection and sequencing of packets into a data stream.
| TCP |
Transmission Control Protocol. Ultra-reliable protocol that makes sure all data packets arrived, and are in proper sequence. Reacquires any corrupted or dropped packets from the sender's transport layer. |
| UDP | User Datagram Protocol. Doesn't check for dropped or corrupted packets ("unreliable"). Good for audio/video transmissions, and where the application implements error-correcting codes. |
Defines packet APIs. Processes packets. Handles network addressing.
| IP |
Internet Protocol. What the Web uses. What Java speaks. |
| IPX |
A protocol used on NetWare networks. |
| AppleTalk |
Apple's networking protocol for MacIntosh. |
| NetBEUI |
Microsofts' networking protocol for Windows for Workgroups and Windows NT |