The Mesh, the computer network of 2039, is not the Internet. It is not a world-wide network of computers, linked with fast and reliable networking, that exchanges untold amounts of data, including real-time video and streaming media.
What it is, is an unreliable and slow means of linking together hundreds of nearly-isolated networks worldwide, a best-available-but-worst-imaginable solution that, for all its flaws and oddities, nonetheless works. If only just. It is slightly better than nothing at all.
Black Skies killed telecommunications – radio, microwave, telephone, telegraph, fiber optic cables, modulated power lines, pulsed signals, and nearly ever other form of communications tried since 2026. With all of these, as soon as the signal gets more than two to three miles away from its source, it just fades out. It become indistinguishable from noise.
The primary exception are purely visual communication methods, like semaphore, signal lamps, and smoke signals. Also excepted are mid-to-low frequency radio, otherwise known as shortwave.
Shortwave radio is highly limited in bandwidth. It is also easily disrupted (meaning information can get corrupted), and can go out for hours (up to a day). Given these limitations, the fact that the Mesh works at all is amazing.
Most major North American polities operate their own, very different, computer networks. They each have their own architecture, hardware, and strengths and limitations.
Each of these local nets has one or more Mesh nodes, which allows them to send and receive signals from the other networks. Messages come from their local net, through their node to another node, then on to its attached network. The Mesh is a bridge between computer systems that would otherwise be totally isolated.
In a Mesh network, each node talks to all the others at the same time. There are 30 or so nodes in North America (some Outlaw settlements operate nodes, every Chartered Company does, and some of the major polities operate more than one), and a maximum of 50 can be on-air simultaneously. Each of these nodes broadcasts on one channel, and receives on every other channel. This maximizes the bandwidth of any single node.
The Mesh is limited to 50kbps theoretical maximum throughput. More reasonably, people get around 40kbps effective speed (when error correction, routing information, and other overhead is taken into account).
In perspective, 50kbps is slower than an old 56k acoustic modem, and 40kbps is just a little faster than a 33.6k modem. The Mesh talks about as fast as the old squealing modems used to.
Any and all information that needs to be sent from one net to another has to travel through that single, slow connection. All email, all web pages, any and all information that bridges from one network to another.
As a result, cross-net traffic is expensive, and only done when the expense justifies it. As with all other changes in communications technology, this has heavily impacted how people send, receive, and perceive information.