Common Data Network Symbols

Networking is a very graphically oriented subject, and icons are commonly used to represent networking devices. On the left side of the diagram are shown some common devices which often originate messages that comprise our communication. These include various types of computers (a PC and laptop icon are shown), servers, and IP phones. On local area networks these devices are typically connected by LAN media (wired or wireless).

The right side of the figure shows some of the most common intermediate devices, used to direct and manage messages across the network, as well as other common networking symbols. Generic symbols are shown for:
Switch - the most common device for interconnecting local area networks
Firewall -provides security to networks
Router - helps direct messages as they travel across a network
Wireless Router - a specific type of router often found in home networks
Cloud - used to summarize a group of networking devices, the details of which may be unimportant to the discussion at hand
Serial Link - one form of WAN interconnection, represented by the lightning bolt-shaped line

The elements of networks

The diagram shows elements of a typical network, including devices, media, and services, tied together by rules, that work together to send messages. We use the word messages as a term that encompasses web pages, e-mail, instant messages, telephone calls, and other forms of communication enabled by the Internet. In this course, we will learn about a variety of messages, devices, media, and services that allow the communication of those messages. We will also learn about the rules, or protocols, that tie these network elements together.