Chapter 6: Network Hardware

Chapter 6 dealt with the hardware side of things in detail. The first thing the chapter covered was various types of NIC (Network interface Card). NICs come in a dizzying array of different types, and are available for just about every sort of expansion connector known to computing (PCI, PCIe, FireWire, USB, CardBus and ExpressCard for laptops, and built-in ones integrated into the motherboard of a computer) Regardless of how you connect them or what kind of cable (or radio signal) they use, however, a NIC is fundamentally a NIC. They're used to convert data into electrical impulses, light, or radio waves for transmission to the next NIC and for converting those same impulses, light beams, or radio waves back into data when it arrives.

The chapter also covered repeaters, hubs, switches, bridges, and routers. These devices, collectively, form much of the backbone of a network, and perform functions analogous to stoplights and street signs in a city, managing where traffic flows, what gets priority, and that everything (or at least as much as possible) gets there intact. Repeaters and hubs are the simplest, just rebroadcasting whatever comes into them. The biggest difference is that a repeater only broadcasts out to one output, whereas a hub will have several. Hubs have largely become a thing of the past – switches these days are so cheap that you'd be silly not to use one. Switches and bridges connect segments of a network to each other and operate by actually sending packets just to their destination IP rather than just broadcasting them like a hub. Small wonder they're more efficient. Bridges are basically two-port switches, used to connect just two segments together. Routers are like switches on steroids. They have an array of filtering, reporting, and security features built in. They are more than one needs sometimes, but they're great for setting up intra-nets that still connect to the Internet, because they can route traffic from an entire network out to the Internet via a single public IP.

The chapter was useful, but seemed a touch overlong for the material it covered – these connectivity devices are vital but somewhat self-explanatory. Then again, maybe it's just prior knowledge talking.