To the uninitiated, computer networking is a black art, best left to wizards and witches who understand the magic of Cat 5 cable, Gigabit Ethernet, and full-duplex networking. While you may never be ready to set up an IP routing table, though, that doesn't mean that you shouldn't understand a little about what's going on under the hood, especially if you're the person signing the cheques. Here's a quick guide to read so that your eyes won't glaze over when someone begins talking about hubs, switches, and routers.
If you want to connect your computers, servers, and printers together in a wired environment, then at the very least you'll need a hub. A hub has enough spaces (Ethernet ports) for each of your devices to connect to. When one connected device wants to talk to another, it sends the information via the hub.
The hub is the loudmouth of the network world. It talks loudly, and understands nothing. It doesn't care about the content or the destination of the data it receives. When it hears from one device, it broadcasts that message to everything else that it's connected to. If your desktop asks the local printer to print a file, all the other devices hear about it.
A switch does the same thing as a hub, sending messages between the devices connected to it. The difference is that the switch knows how to whisper. When the desktop asks the printer to print its file, the switch only sends that message to the printer, and no other devices hear it.
The switch does this by remembering each device's individual Ethernet address, known as a MAC address. It keeps a switching table with these addresses, which lets it transfer information directly between them. This saves on unnecessary traffic, which wastes bandwidth. It also improves security, because devices see network traffic on a need-to-know basis, rather than watching everything that passes between other devices on the network.
So, should you buy a hub or a switch? The answer these days is that switches are almost always better, especially now that the price delta between the two products has narrowed.
There's one other device that you should know about in the context of hubs and switches, and that's the router. The best way to think about hubs and switches is that they create the network in your office, whereas a router connects this network to others over a wide area.
Let's say youR company has a headquarters and a regional office. Each office has a dozen or so desktop and laptop computers, a server, and some printers. The computers talk to the server in the local office using a hub or a switch. They talk to the printers in the same way. But what if Bob in Cheltenham wants to access a file on a server at the HQ in Leeds? His computer talks to the router on the local network, which then sends the traffic to the router at the Leeds office. That router finally talks to the destination server on its local network.
Now that you know the basics of these network devices, you can begin making smart decisions about which ones to invest in and where to put them. When the network technician comes to you with a requisition form, you'll be able to ask if they really need a managed switch, and who's going to configure it. But if they offer you the Internet in a box, please be careful with it.