A network consists of two or more nodes connected to one another via communication paths such as cables, telephone lines, radio waves, satellites, or fiber optic. For those of you that are wondering what a node is, it is simply any device that can be connected to a network, such as a computer, printer, or telephone. A network can be connected with other networks and subnetworks. In fact, the Internet is simply a massive network of networks. The easiest network to understand is a local area network (LAN).
A local area network is a collection of devices in a single geographic location that is used to connect, communicate, and share resources among devices. These devices and endpoints house all the applications and services needed to run an organization and are only obtainable from a device that is attached to the LAN. This is meant to secure and “enclose” the network to provide better services and a more secure connection. For example, a LAN consisting of five office desktops connected to one another and a printer via a router provides communication among these devices with no need for an outside network, enhancing security and service.
When designing a LAN, it is important to consider the general configuration of the network, or network topology. Common network topologies include bus, ring, star, and mesh architectures.
A wide area network (WAN) is a collection of LANs connected together over a large geographic location. For example, the LAN at an organization’s headquarters could be connected to the LANs at five of their branches to comprise a WAN. You can think of the global Internet as one big WAN.
Once a network is set up, it needs a way for each node to communicate with the others. The set of rules that govern the way a node transmits information is called a communications protocol. The communications protocol that governs the Internet and similar computer networks is TCP/IP. TCP/IP consists of two layers of protocol: Transmission control protocol (TCP) and Internet Protocol (IP).
The TCP layer assembles a message or file by breaking it up into small units of data, called packets, that are then transmitted over the internet, received, and reassembled into the original message or file. Meanwhile, the IP layer ensures that the message or file arrives at its intended destination by addressing the message or file. Even though each packet may be routed differently, the IP layer ensures that each packet arrives at the same address, while the TCP layer ensures that each packet will be reassembled into the original message or file.
For this process to occur efficiently and securely an organization needs to ensure that its network is designed correctly and that the proper router, switch, and security devices are in place.