6 Required Components of a LAN
Only the very smallest companies can be run without a computer, and once you've got even a handful of computers you'll probably want to network them. A Local Area Network, or LAN, turns individual computers into a shared working environment, in much the same way a shared project turns individual employees into a team. A LAN might include thousands of computers or just a few, but all LANs are made up from the same basic handful of components.
For users, a network is all about the software they actually deal with, whether it's a word processor, accounting software or some kind of high-end custom program. Underneath that, making it work, you'll find a network-aware operating system, the drivers that help your computers talk to the networking hardware, and all the specialized code that handles communications between devices. Those are the software components of the network.
So what are the hardware components of a LAN? Those include your actual computers, their network interfaces, and all of the switches, hubs, routers and other special-purpose bits of tech that route your communications. Finally, there's cabling or its wireless equivalent. All these components work together to create a functioning network.
The whole point of a LAN is to have users working together collaboratively, or at least sharing the network's resources, so all of those users need to have a way to access the network. That's done through the individual computers, or workstations, that are connected together to make up the LAN. Those computers can be pretty much anything. A given office might contain everything from low-end laptops or Chromebooks to high-powered engineering workstations, with plenty of standard-issue machines in between to handle the routine duties of accounting, word processing, point-of-sale and so on. In a wireless network, even a tablet or a cell phone can be treated as a workstation.
Often, the most important part of designing a LAN is how you group all those users' workstations together. Sometimes it's as simple as connecting everyone in the same physical space, but what if their needs are different? A basic Wi-Fi signal is fine for guests and casual users, for example, but engineers or video editors will need the fastest connection you can give them. Grouping users onto different sub-networks, where they can share separate sets of resources, is often your best option. In that scenario, a group of power users scattered across offices on two or three separate floors might share a network that communicates at speeds of several gigabits per second, while everyone around them uses a slower network.
Network Interface Cards and Drivers
Your individual workstations won't be part of the network unless they have some way of communicating with everything else that's on the LAN. That requires something called a Network Interface Card, usually shorted to NIC. This provides a way for your computer to connect to the LAN and exchange information with it. Most computers are built with two kinds of NIC already on board, one that uses Wi-Fi and one that uses an Ethernet connection. You can use the built-in NIC to connect with, or you can install a separate specialized card to meet your company's individual needs. You might want a higher-performance card than the one that comes built in, for example, or you might opt to network with fiber optics for a performance upgrade. In those cases, you'll need to buy a separate physical card and install it in the computer.
The hardware of the NIC also requires a bit of added software to make it run. This is called a "driver," which interprets the commands coming from your operating system into instructions the NIC can recognize and work with. Your operating system has drivers built in for most cards, so when you restart your computer it'll just recognize the NIC and work with it. Sometimes you'll need to get a driver from the card's manufacturer instead, because it provides higher performance, better reliability or just unlocks some key features you wouldn't get with the standard driver. Windows updates its own drivers but not third-party drivers, so you'll have to check those periodically and install any updates yourself. If you've installed your driver from an authorized source, Linux will keep track of third-party drivers and update them along with everything else.
There's definitely a cost attached to creating and maintaining a network, but it pays for itself in many ways. The most important measure is improved productivity, but the option of sharing resources is the kind of up-front cost saving that any bean-counter can relate to. Consider printers, for example. Most of your users probably need the ability to print, but only a few of them will print high volume on a regular basis. Rather than parking a printer on every desk, where most of them will gather dust, you can have everyone else share a small number of networked printers. There will always be some situations where you'll need to allocate or "dedicate" a resource to one specific user, or one specific group of users, but that's fine. If you only have one person doing large-scale artwork, or creating oversized drawings and blueprints, there's no need for everyone else to have access to their printer or plotter.
This part of your LAN also includes all of the hubs, switches and routers that physically connect the cabling between devices across your network, and between your network and the internet or your own company's larger Wide Area Network. A WAN includes things like routers and signal extenders that can stretch your network's reach. Normal users won't need to know how to use them – or even care that they exist – but without them, you wouldn't be able to connect and exchange information. Think of them as the electronic equivalent of the traffic signals, intersections and ramps that route the flow of vehicles around a city.
In small networks, each of the computers on your LAN is pretty much the same. In a larger network, you may also have physical servers, racks of computers that provide high-volume storage and processing power to the network. Traditionally those were kept in-house, but the rise of cloud computing – massive clusters of servers housed off-site, and accessed over the internet – means the servers can be in remote locations or even operated by a third-party provider, usually a major company such as Amazon, Microsoft or Google.
Networking Operating System (OS)
One of the most crucial pieces of a LAN is the software that juggles all of your network's resources and users so that everybody has what they need. It keeps track of what devices are on the LAN, what programs are running, what information is being circulated around the network and which of the network's resources are needed to make it all work. In the early days of networking, from the 1980s to the beginning of this century, you needed a separate program like Novell's Netware or Banyan's Vines to do that. These were complex, expensive programs, and it took a lot of training to learn how to use them properly.
Now, Windows, OS X and Linux all have the ability to run networks without needing a separate OS. They can even talk to each other, so your IT people might use Linux to provide network services to Windows users in your office and Mac users doing graphic work in your marketing department. Everyday users won't see or use those advanced features. That's the job of your network administrator, who has a higher-level password and can add, subtract and reallocate users and resources on the LAN.
In a small office sharing five computers, a printer and a Wi-Fi connection, that administrator might be one person with a bit of basic training and maybe a good reference book. In a larger business, you might find a whole IT staff with dozens of people handling those functions. As you grow, your needs will grow, and you'll need people with better skills to keep everything working properly.
The most visible part of the network, for users, is their actual working software. In the early days, for example, a network was the only convenient way multiple users could collaborate on a single Word document or an Excel spreadsheet. That can be done in the cloud now, but other collaborative tools like Slack and Evernote make it easier for all of your people to work together. You'll also rely on your in-house network to give users access to your company's main databases, accounting software and other core programs, whether they're housed on physical servers in your own data center or live on a cloud-based server under a contract with Microsoft, Amazon, Google or some other provider
There's a second set of network-aware programs that fewer people will use, but they're equally important. These are the tools your administrators use to monitor the LAN's performance and security. Some of those tools are built right into the operating system, of course, but others are supplied by third party vendors or might even be written in-house by your own programmers. Keeping your network secure is especially important, because if a hacker gets access to sensitive data about your operations or your customers, things could get very ugly indeed.
A Communications Medium
You can have everything you need for a LAN in your offices, all freshly installed and gleaming, but they're so many separate lumps of hardware until you actually give them a way to communicate. You need to connect all of those computers together, either physically with cabling or virtually through a Wi-Fi connection.
In the early days of networking, you'd usually use a heavy coaxial cable, very much like those used for cable or satellite television. Over time, most networks switched to a different kind of cable, called twisted pair, with pairs of wires running through a flat, lightweight cable that looks like – and is – a variation on the wiring used for landline phones. Twisted pair is lighter and easier to install, and the phone-style plugs at the ends of the wires snap easily into the jacks on your computers, switches, hubs and other network devices. You'll often hear this kind of connection referred to as Ethernet plugs and jacks, though that's not strictly correct. Ethernet refers to how you communicate across the cable, not to the cable or connector itself, and it was used on the older networks with coaxial cables as well.
A wireless network, or WLAN, uses radio waves instead of physical wires to send signals between the computers and other devices on your network. There are two separate sets of frequencies you can use, depending on your needs. Most older wireless networks use the 2.4 GHz band, while newer devices can also make use of the 5 GHz band. They each have some advantages. A 2.4 GHz signal will give you longer range, and it's better at going through walls, which can be important in a big office. Unfortunately, it's also more prone to interference, because there are an awful lot of devices out there that share the same frequencies. The 5 GHz band isn't as good with walls, and it's best over shorter distances, but where it works it'll give you a better signal.
Fred Decker learned business fundamentals at second hand as an insurance and mutual funds broker, and at firsthand as a retail store manager and the chef/proprietor of his own restaurants. He has written hundreds of business-related articles for sites including Zacks.com, Chron.com, Vitamix.com, Bizfluent and GoBankingRates and many others. He was educated at Memorial University of Newfoundland and the Northern Alberta Institute of Technology.