Hey man! What’s a WAN?

Some IT networking fundamentals you should know for cybersecurity! A quick article for your learning pleasure.

Did you know that fungi and IT networks actually have a lot in common. Photo by Timothy Dykes

What’s a WAN, man!?

A Wide Area Network (WAN) is a type of computer network that connects Local Area Networks (LANs) over a large geographic area. The internet is the ultimate WAN, connecting every LAN to every other LAN across the entire globe. Facilitating communication between geographically dispersed sites requires a WAN, which is simply an internetwork spanning a large geographical area. The primary difference between a WAN and an internetwork is distance. While WANs use services of carriers or service providers, such as phone companies and ISPs, for network connections, internetworks are confined to a building or campus where the internetwork’s owner owns and operates all the technology. WANs use serial communication technologies that can span distances measured in miles or kilometers, compared with typical LAN technologies that span distances measured in meters.

WAN Devices

Several devices are used in a WAN to facilitate communication between geographically dispersed sites. These devices include:

1. Modems: A modem is a device that converts a sending computer’s digital signals to analog signals for transmission over phone lines and then converts analog signals to digital signals for the receiving computer. The term “modem” is just a shortened form of “modulator/demodulator.” A digital signal is represented as a square wave, a signal that uses binary 1s and 0s to represent two possible states. An analog signal, on the other hand, is a signal represented by a sine wave that varies over time continually and smoothly.
2. Channel Service Units/Data Service Units (CSUs/DSUs): A Channel Service Unit/Data Service Unit (CSU/DSU) is a device that creates a digital connection between a LAN device, such as a router, and the WAN link from the service provider. A CSU/DSU terminates the digital signal from the LAN and converts it to a format that can be transmitted over the WAN link. It also performs error checking and control functions to ensure that the data is transmitted reliably.
3. Routers: The routers role in a WAN usually means that it’s a device connecting a LAN to the WAN service provider. In most cases, it connects to the modem or CSU/DSU, which then connects to the link from the WAN provider. A router directs data traffic between networks, ensuring that data is sent to the correct destination. It also provides security by filtering out unauthorized traffic and can prioritize data traffic to ensure that critical data is transmitted first.

Conclusion

A Wide Area Network (WAN) is essential for facilitating communication between geographically dispersed sites. It spans a large geographic area and connects Local Area Networks (LANs) over a wide distance. WANs differ from internetworks in that they use the services of carriers or service providers, such as phone companies and ISPs, for network connections. Several devices are used in a WAN, including modems, Channel Service Units/Data Service Units (CSUs/DSUs), and routers, to facilitate communication between sites. These devices convert digital signals to analog signals for transmission over phone lines, terminate digital signals from the LAN, and direct data traffic between networks, ensuring that data is sent to the correct destination.