#edtech for #edleaders: Fundamental Concepts of Networking

Fundamentally, computer networks are simple systems. To build a network, one provides a pathway to move data from one node to another (through electrical signals transmitted over wires or radio signals that travel through the air), gives every node a unique address (so the network “knows” where to deliver packets), and then keeps track of it all (so the network “knows” where to direct each packet of network information.)

A consumer network can be set up for less than $100 and has sufficient capacity to connect a small number of devices of devices to the Internet with acceptable performance for the few devices using it at any moment. To create a consumer network environment, one visits an electronics store or office supply store (or web site) and purchases a device that functions as the gateway between the computers connected to it and the Internet and that assigns addresses to each node and routes packets to each node. The nature of the cable that connects to the circuits outside the building depends on the service purchased from an Internet service provider (ISP); sometimes it is a coaxial cable, sometimes an Ethernet cable, and rarely a telephone cable. Typically, one configures the following on a consumer network as well:

  • Wireless access, so that mobile devices can connect to the network;
  • Filtering to prevent access to certain sites or to deploy other rules to limit what can be accessed, when it can be accessed, and on which computers it can be accessed;
  • Firewall to deny unwanted incoming traffic access to the network.

The ease with which one can set up a consumer network can lead technology-savvy consumers (including teachers and school leaders who may be involved with IT management in schools) to misunderstand the task of managing the networks necessary to provide robust and reliable network connections in schools where IT professional install and manage business or enterprise networks. Consumer devices are designed to be “plug-and-play” systems, so many of the essential functions are preconfigured into the devices as defaults settings and these will work with the defaults settings that are set on consumer devices. As long as nothing is changed, and the number of devices is fewer than about 10, a consumer network will be reliable and robust.

Business class networks are built upon network devices with circuits that provide robust and reliable connections to several tens of users. In all but the smallest schools, enterprise networks are necessary to provide sufficient performance. Enterprise networks are very sophisticated and the devices necessary to provide adequate performance on an enterprise network are far more expensive than consumer or business grade devices. Consider, for example, switches; these devices provide additional ports, so devices can share a single connection to the network. On a home network, one might use a switch to allow three desktop computers in a home office to access the Internet through a single cable. On an enterprise network, the system administrator might use a managed switch to connect two new computer rooms full of desktops to the network. The switch (with five ports) for home would cost less than $50, but the enterprise switch (with 48 ports) would cost around $5000. Notice the difference in relative price; consumer ports are about $10 per port. Enterprise ports are more than $100 per port!