It's fairly simple, actually. You would need a bit of an understanding of how TCP/IP works to make sense of it. Everything done on the 'Net may seem like a seemless stream of information, but it's not. Everything is broken down into "packets" that are a fixed length and format. Each packet, like your standard postal letter has the source and destination routing, (the TO:
and FROM: on the envelope) as well as a fixed block of plain text.
Information that's larger than one packet is broken down into multiple packets. Even mulitmedia (audio, video, etc...) is first converted to text and broken down into packets. It's the responsibility of the recieving end to decode and reconvert the packets into audio/video. (This is why multimedia streams can sometimes be choppy. But I digress.)
Now then, we can look at each device, it's function and go forward from there. A car analogy works fairly well for how networking works. Consider each packet as a car travelling on a road.
A hub is a "dumb" device that allows multiple computers to communicate with each other. Think of it as an uncontrolled intersection on the highway - no stop signs or lights. As you can imagine, without any sort of control, crashes are bound to occur. And they do. Frequently.
Fortunately, no one, or nothing really gets hurt. The system that sent the original packet merely resends it (the car in our analogy) until it does manage to get through.
A switch is like a hub, except that it has traffic control built into it. It has the means to control which computer on the network talks to the
other(s) and when. Think of it as a traffic cop at the intersection and it's directing traffic. Since there are fewer crashes, throughput is a lot faster and more reliable.
A router is a device that sits between your DSL (or cable) modem and directs traffic. Think of it like the guy in an old fashioned mail room who sorts incoming mail into the appropriate cubby hole by looking at the address it's coming from and where it's going. Routers use something called Network Address Translation (NAT) to do this.
When you sign up for DSL (or Cable), you get one TCP/IP address allocated for your use. Each computer, however, needs an individual and unique IP address in order to get the appropriate packets directed to that machine. A router has the ability to create an independent set of IP addresses on the "inside" which then allow you to share one "outside" IP address with up to
255 different computers. (side note: The actual number of devices a router can handle may vary by manufacturer/model. See the documentation for more info on that.) NAT allows the router to flag each packet and keep track of where it came from and where the replies to those packets are supposed to go.
Making sense of it all...
Now then... Things get a bit tricky. There are "combo" devices available on the market. While they're all "routers" they also sometimes have a switch built in that allows you to save a power plug port - one fewer device to plug into the wall/surge protector strip. Most multi-port routers contain a switch, rather than a hub. As long as it's sorting the NAT data, it might as well manage the traffic on the ports.
And then there's wireless... The latest trend is to have WiFi access points built into routers. If you've got a laptop with a wireless radio built in, this may suit your taste. However, if you simply have three desktops to connect, it may be a solution worth looking into. These devices tend to, like their wired only bretheren, have NAT built in and can typically support up to 255 devices (check the documentation, your mileage may vary). Usually, wireless routers do offer at least one wired connection port for configuring and managing the router.
Wireless can be a good or bad thing depending on how it's configured. If you simply go for the default setup, you will probably be leaving your wireless access point wide open for ANYONE in your neighborhood within range with a wireless enabled laptop to hitch onto your network and potentially cause problems. You might not mind if your neighbor taps in and uses your DSL connection to say, download some songs or a movie until the MPAA or RIAA stormtroopers show up at your front door.
Wardriving is an activity where a hacker drives around a given area looking for networks that are left wide open (hence the "driving" part). Once he finds a network that's wide open, he can do some pretty nasty things - like planting viruses on your computer, grabbing your personal financial data, sending out a flood of spam, etc... in addition to other nefarious activities.
On the bright side of wireless...
If properly configured (see the instructions for more details) wireless can be a good thing. You can connect anywhere as long as you're within range of the router/access point and you're not dragging a bunch of wires (except maybe the power brick) along for the ride. You have to configure each workstation correctly with the matching encryption code you created on the router/access point.
Most all routers today come with firewalls built in as well as switches.
Most of them are adequate for keeping the bad guys out (for the moment, at least). As for needing a software firewall as well... That would depend largely on how paranoid you choose to be. It doesn't hurt to have one, but then again, it does take up resources which can slow your computer down. On the other hand, given the recent Cisco fiasco where a so called "security researcher" disclosed methods for attacking Cisco routers, it doesn't hurt to have a second line of defense.
So then, how do these devices get put together?
First, there's the phone jack at the wall. Next, there's the filter (supplied with your DSL installation kit). Then, you've got your DSL modem.
This would plug into the router's WAN port. You then simply plug your computers into the router's LAN ports. This is assuming you've got a router with multiple ports.
If you're going with a separate switch, everything is the same until you get to the router. You would plug the router's LAN port into any port on your switch and plug your computers into the switch.
The first option as mentioned above, requires one fewer plug on the surge protector and in all probability is cheaper. Wireless has it's place, but opens a kettle of fish best left covered for novice users. If you do decide to go wireless, best to read the instructions and follow them very carefully or have your friendly neighborhood computer geek give you a hand setting it up.
One other consideration for wireless... Most desktops do not come with wireless built in. You will need a wireless network card for each machine before you can connect to the access point/router. This, of course, raises the price significantly. CAT5 or CAT6 network cable is significantly cheaper.
CAT5 and CAT6
CAT5 and CAT6 are designations for network wiring. They generally come in fixed lengths from 3 feet to 50 feet. The numeric part of the designation (the 5 or 6) has to do with the quality of the wiring inside the cable and how much data it's rated to move. CAT5 is suited for 10/100 million bits per second (10-BaseT or 100-BaseT) networking which is typical for most home networking applications. CAT6 is a newer standard that's designed to handle gigabit networking (1000-BaseT) or 1000 million bits per second throughput.
While it's a nice thing to have, it's more bandwidth than most home networks need - even if you're sharing video over your home network. Given most DSL tops out at 1.5 million bits per second, and cable's best is about 3 million bits/second, a typical 10/100 network is more than adequate unless you're frequently copying HUGE files between your computers. And by HUGE - I mean ones that are a gigabyte or larger. A network that handles 100 MBits/second is plenty fast for most typical applications.
In conclusion, the simplest setup is generally the best. The fancier gear you add (while being ultra cool) generally means you will need to jump through more hoops to get it working. A regular wired multi-port router with say, 4 ports such as the Linksys BEFSR41 or the DLink DI-604 would be more than adequate for your immediate needs.
Submitted by: Pete Z.