What’s a WAN?

March 7, 2024

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Welcome again to TeleGeography Explains the Web. We have reached the finale of our five-part collection that makes good on our identify, actually explaining the ins and outs of the interwebs.

Over the previous 5 weeks, we have endeavored to elucidate exactly how knowledge strikes world wide, masking the fundamentals of web, transport networks, knowledge facilities, and the cloud alongside the way in which.

At the moment we reply the lingering query: What’s a WAN?

First, let’s get definitions out of the way in which.

WAN stands for vast space community, which got here out of the time period LAN, or native space community.

Older avid gamers may recall LAN events. To play towards each other, you’d bodily carry PCs right into a room and join them with Cat6 cables. The WAN is similar thought, however wires span a lot bigger distances, traversing the globe.

The unique non-public WANs had been associated to one thing we already mentioned: the on-premises knowledge heart.

When firms began transferring towards digital transformation— making all types of enterprise processes computer-based as an alternative of analog—they wanted to attach sure workplaces to the info facilities arrange in bigger headquarters or campuses.

At first, this was primarily a community of personal traces, like these we mentioned within the transport networks episode. The upshot is rather like it sounds: a company would reserve a line on a provider’s community that belonged fully to them for an outlined quantity of bandwidth.

Again then, it was often what we known as “protected service,” that means the non-public line was a hoop relatively than a single line in order that it may very well be self-healing if there was a fault. A company would lease a personal line, again then usually SONET or SDH, from a provider to immediately join an workplace to a knowledge heart website they owned.

This was usually a hub-and-spoke setup with all traces converging on the websites with the info heart. So, for instance, an organization would buy non-public traces from their key workplaces in North America again to headquarters in NYC. Then maybe they’d do the identical factor with European workplaces again to an HQ in Paris or Frankfurt. The benefit right here is that these leased traces belonged fully to that company, so that they had been safe, protected, and didn’t become involved within the site visitors jams of the general public web.

Ultimately, the digitization of the company turned full sufficient that they wanted many such traces in redundant connections to permit knowledge to movement between the workplaces themselves relatively than route by means of the HQ or DC websites after which again out. As you’ll be able to think about, redundant non-public traces between all workplaces can’t solely develop exponentially in quantity, but additionally change into prohibitively costly.

However that is just the start of the story.

Pay attention beneath to brush up on the evolution of the WAN and listen to from my colleague Brianna Boudreau, TeleGeography’s present SD-WAN guru.