Demystifying a Small Business Network Networking 101: Getting Up to Speed with a Basic Network Joe Moran
Whether your business is already running on a computer network or you're thinking about taking that step, understanding how a network works is more important than you might think. Even if you hire someone to set up a network for you, understanding the basics will help when it comes time to buy a new piece of networking gear. You also need to understand what the person who sets up the network — whether it's an employee or local computer guy — is talking about so you know you're getting the straight scoop.
We'll try to demystify things a bit for you by outlining the basic components of a typical network and explaining how they interact with each other. Don't think of it as networking for dummies, but rather as networking for those that just want the basics with a minimal amount of technical mumbo-jumbo.
A typical network starts with one or more computers linked together by special cabling through devices called switches. Switches connect to another kind of device called a router, and routers in turn connect to yet another device known as a broadbandgateway. Since the broadband gateway is the linchpin of many small business networks, we'll start with it and work our way forward (or backward, depending on your point of view) from there.
Broadband Gateways
These days most homes and small businesses get Internet access from either the local cable company or the phone company. A company that provides Internet access is known as an ISP, or Internet Service Provider. In order for you to gain access to their network, an ISP provides a device generally known as a broadband gateway, (though it's also commonly referred to as either a cable modem or DSL modem depending on the type of service you have).
If you think of the Internet as an interstate highway, the broadband gateway is essentially the exit to your network. Most broadband gateways are ostensibly designed to connect to a single computer; so if you have multiple computers that each need access, that's where a router comes in.
Routers
The basic function of a router is to connect one network to another. Routers receive information (data), or traffic, from other networks and either deliver it to the correct computer or forward it on to another router for delivery. Organizations with very large networks often use multiple routers to link the networks of different departments (say, Sales, Marketing, and Human Resources), but in the context of a typical small business network, the router's job is to act as an intermediary between the company network, and that of the ISP.
Routers designed for small business networks usually have a security device known as a firewall built into them. Firewalls work by monitoring the traffic coming into the network and scanning it for potential threats. If any questionable traffic is detected, the firewall blocks it, preventing it from entering the company network.
Switches and Cables
The way computers link to a router and to each other to form a network is through devices called switches. (We'll set wireless networking aside for the time being, because we'll cover that in an upcoming article.) The actual physical connections are made with cabling — commonly known as Category 5, or Cat 5 — which resembles conventional phone cord. (The two are actually quite similar, though network cable is thicker and uses a larger connector.)
Computers connect to switches in a hub-and-spoke arrangement; think of it as a bicycle wheel, with the switch at the center and spokes (the cables) radiating from the center to the wheel's rim to each individual computer.
Routers designed for home and small business networks typically have the switching technology built into them, so one device performs both functions. These combination devices let you connect at least four computers, and sometimes eight.
The overwhelming majority of network switches and cables are based on a technology called Ethernet, and there are two major types of Ethernet used today. The most common type is called Fast Ethernet, which can transmit a maximum of 100 megabits of data per second. By contrast, Gigabit Ethernet offers 10 times the performance, or 1,000 megabits per second. (Because of network overhead and other factors, the actual performance you get from either version of Ethernet is usually less than half the quoted figure.)
