Demystifying Routers and Switches

Launching a business shouldn't be as complicated as launching a shuttle. But with terms like "routers," "switches," and "firewalls" to decode, entrepreneurs can't help but feel lost in space as they set up their first corporate network. Fortunately, as complex as the network components can seem, their functions are quite simple - and educated purchasing decisions are within easy reach.

While you and your employees use information in complex ways, data is typically accessed in just two: pulling information from the Internet, such as news stories or downloading files, or sharing information, like Excel and PowerPoint documents, with team members.

When an employee - let's call him Barry - clicks on a news story, it's the router that seeks out the necessary information online and pulls it down to the network. At the same time, the router is ignoring the billions of other web pages that it could grab, but that Barry doesn't want to read.

As smart as the router is at knowing precisely which information to grab and which to leave behind on the Net, it hasn't a clue about what to do once the data is on your network. That's where the switch takes over.
Switches pick up the data from the router and forward it to the right computer on the network; in this case, Barry's notebook. Switches also control internal traffic, so that jams are kept at a minimum. So while Barry is forwarding his article to Susan down the hall, Susan's Excel file - on its way to Barry - won't collide with the article and cause a jam...network delays that get on everyone's nerves.

Along with telling data where to go on your network, switches can manage how fast it gets there. Just as fire trucks enjoy exclusive traffic lanes in cities to speed their way, so too can certain types - or sources - of data, be given right of way priority on busy networks. For example, the boss' email can be given faster delivery rights than the janitors' web surfing traffic. This kind of prioritisation is critical for applications like Voice-Over-Internet-Protocol. Most companies choose to prioritize VOIP traffic over all other communications, because it's more important to have a smooth conversation with a client than to wait an extra millisecond for a PowerPoint to download. Also, some "roads" can be set aside for printing or file sharing to speed those tasks.
But, back to Barry and Susan. How do we know that the article Barry downloaded, or the file Susan emailed to the Paris office, doesn't contain a virus or a corporate secret? That's where firewalls come in to play. Firewalls exist between the router and the switch, blocking viruses from entering the network and scanning for content policy violations, such as bad language or keywords that signal the sharing of confidential information.

Choosing Routers and Switches
The type of router you'll want to get will depend on two factors: the type of Internet connection and its speed. The typical types of connections are dial-up, Digital Subscriber Line (DSL) and cable. Dial-up access is the most widely available for small businesses, since it requires only a basic telephone line to use. Unfortunately, it's often the slowest road to the Internet, requiring a user's computer to "call" the Internet Service Provider to access the Internet, and offers the slowest method of data transmission once a user is online.

Typically, once a company is at the networking stage, it has outgrown the constraints of dial-up. DSL is a technology that uses the same copper wires as dial-up, but speeds data transmission in two ways. First, DSL is "always on," meaning you don't need to waste precious minutes "signing on" each time you connect to the Internet. Second, DSL performs like a "fatter" pipe, delivering data at least four times the speed of dial-up. Since DSL uses traditional phone lines, its available almost anywhere, requiring only a small DSL modem to be attached to your network. "Cable" uses cable television networks to transmit Internet data instead of TV images and sounds. Since many office buildings aren't wired for cable, the costs to establish such a connection can sometimes be higher than setting up DSL.

As for speed, you can purchase routers at the T-1, T-2 and often through the T-4 levels. Each level reflects a higher rate of speed, and while the technologies behind each of these standards are complex, finding the right choice for your business is easy. Simply tell your networking provider what speed your broadband connection is running, and they will match the proper router with your network.

There are a few more questions you'll want to ask when deciding on a switch. How fast do you want your network to operate? To what degree would you like to customize which files get the right of way? What level of security do you need? Some switches can create virtually segmented networks, adding an extra barrier between workgroups, such as Sales and Human Resources, which aren't allowed to see each other's information. More advanced switches can also detect when someone has plugged an unauthorized notebook into a printer port (ports are entry ways to your network) and disable the offending device. Finally, keep in mind that switches work for up to 48 users. So if you have more employees, or they're dispersed across different floors or states, you'll need more switches.

Regardless of which router or switch you choose, it may be best to avoid combination devices. Some routers have switches built into them; some routers have firewalls built in. While these products might look tempting, they concentrate risk. If one portion of the device fails all parts may also suffer. Spread the risk around three separate devices. That way, if the router fails, your employees can still share files. Or if the server goes down, Internet access will continue. Keeping this in mind will ensure bump-free rides for your employees as they traverse your internal network and beyond.

For more information, visit Dell's Server Networking Basics.