RFC 1180 (rfc1180) - Page 2 of 28


TCP/IP tutorial



Alternative Format: Original Text Document



RFC 1180                   A TCP/IP Tutorial                January 1991


   The next section is an overview of TCP/IP, followed by detailed
   descriptions of individual components.

2.  TCP/IP Overview

   The generic term "TCP/IP" usually means anything and everything
   related to the specific protocols of TCP and IP.  It can include
   other protocols, applications, and even the network medium.  A sample
   of these protocols are: UDP, ARP, and ICMP.  A sample of these
   applications are: TELNET, FTP, and rcp.  A more accurate term is
   "internet technology".  A network that uses internet technology is
   called an "internet".

2.1  Basic Structure

   To understand this technology you must first understand the following
   logical structure:

                     ----------------------------
                     |    network applications  |
                     |                          |
                     |...  \ | /  ..  \ | /  ...|
                     |     -----      -----     |
                     |     |TCP|      |UDP|     |
                     |     -----      -----     |
                     |         \      /         |
                     |         --------         |
                     |         |  IP  |         |
                     |  -----  -*------         |
                     |  |ARP|   |               |
                     |  -----   |               |
                     |      \   |               |
                     |      ------              |
                     |      |ENET|              |
                     |      ---@--              |
                     ----------|-----------------
                               |
         ----------------------o---------
             Ethernet Cable

                  Figure 1.  Basic TCP/IP Network Node

   This is the logical structure of the layered protocols inside a
   computer on an internet.  Each computer that can communicate using
   internet technology has such a logical structure.  It is this logical
   structure that determines the behavior of the computer on the
   internet.  The boxes represent processing of the data as it passes
   through the computer, and the lines connecting boxes show the path of



Socolofsky & Kale