Basic Networking
(This is an old article I wrote 4 years ago, but still valid info.)
Networking Basics
So, you want to hook up to the internet well you found the right place for some true information, first off, basic network hardware information:
Whats a hub?:
A hub is basically a “dumb” cable splitter, a good way to think of it as a power strip that you plug into the wall in order to get more outlets, the downside is that all data communication is sent to all the ports, thus taking up the available bandwidth from all other ports. For example, I have 3 computers plugged into a 4 port hub, If computer 1 wants to talk to computer 2 it blasts the data out of the network card and to the hub, which in turn blasts that same data to all of the ports on the hub, so computer 3, even though it wasn’t being talked to will see that data. Bottom line, the more computers you have on a hub, the slower the connection will be. That being said, with only 2-3 computers on a 100mb hub, you’ll never notice the slow down, especially if your only browsing the internet, and or using your xbox to share your internet connection. If your tight on cash, buy a 100mb hub rather than a switch, 10mb would be fine too, but you may see some slow down if your downloading a large file at the same time your trying to frag online with your xbox.
Whats a switch?:
A switch performes the exact same function as a hub, but with some added brains. Like a hub, it will split the connection into as many ports as the switch has, but a switch contains some circity that gives every port dedicated bandwidth, Using the example from the hub description, 3 computers hooked to a switch, if computer 1 wants to talk to computer 2, computer 1 sends the data to the switch, and the switch is “smart” enough to know what port computer 2 is plugged into and send the data only to that port, and comptuer 3 never sees that traffic. So, on a 100mb switch, all comptuers get 100mb of bandwidth reguardless of what all the other computers are doing on the switch.
Whats a router (linksys reference)?:
A router is the next evolution in data transmision. A router IS NOT A SWITCH OR HUB!! it basically has some software in it that can be altered to “route” traffic based on the needs of the owner. It is used to control the flow of data between networks, or computers. For example, if I want all of my data to be transmitted on port 1245 I would program my router to do that with all traffic that comes into it, and have it sent out of it on that port. Or, it can be used as a firewall to block all traffic on port 54321 etc. In the case of the comsumer brand Linksys router, most modles have a built in switch that allows you to plug computers directly into it. With some other models, you have to hook a hub/switch into the one port in order to connect multiple computers. Again, routers, swithces and hubs are all seperate hardware, the manufacture has just combined 2 of them to make it easier for novice users to use. The router then directs all traffic out the Wan connection, or cable/DSL connection thus sharing the internet connection between all of the computers connected to it.
Cat 5 cable info:
I have noticed that people get confused about cables sometimes, weather to use a crossover cable or a straight through cable. First off, there are only 2 types of cables that you need to be concerned about, crossover, and straight through. If a cable is not labled crossover in the store, then it is a straight through cable. The difference in the cables is that in a straight through cable, all the pins line up on both ends of cable, ie. pin 1 on one end goes to pin 1 on the other end, just like an ide ribbon that connects hard drives to your motherboard. In a crossover cable the pins do not go straight through ( hence the name ) When data is going through a cat5 cable, only 4 wires are used, 1,2,3,6 out of 8. in a crossover cable, pin 1 connects to pin 3 and pin 2 connects to pin 6 on the other end.
Also, do not get hung up on the 350mhz cable or other premium cables, it’s just a waste of your money to purchase it. With comsumer level products you will never notice a speed difference between the high end stuff and the premium stuff.
Reason for crossover:
In an ethernet connection there are send and recieve wires that match up with the send and recieve pins on your network card. So if you want to hook 2 computers directly to each other, you can’t use a straight through cable because you would be hooking a send to a send and a receive to a recieve on the network cards. So you use a crossover cable, that connects, send to receive, and send to receive, makes perfect sense huh?
You also need a cross connection when hooking 2 switches or hubs together. Lets say that you need 5 computers hooked up, but only have 2 4 port hubs, you can connect the hubs together and essintialy create one larger hub. The line that connects the hubs has to be crossed somewhere, wether you connect a crossover cable to 2 standard ports on each hub, or you use a straight through and plug it into an uplink port on one of the hubs and a regular port on the other hub. Do not hook a cable to the uplink port on both hubs. Also do not connect a computer to an uplink port. The uplink port is used only for connecting multiple hubs/switches together. I know someone out there knows how to make it work, but for simplicity, and standards, just don’t do it. 
Hooking things up:
PC to PC conncetions can be done in 2 ways, directly with a crossover cable, or through a hub that only requires 2 stratigh through cables plugged into 2 ports in a hub, no crossover required.
To hook a pc to a hub, or a switch you do not need a crossover cable!
If you want to share your internet connection with another computer, or an Xbox, you will need something to provide a link to all of the devices, like a hub, and something to route the internet traffice to and from each device, like a router. The perfect solution to this problem is a linksys router, or similar product, or a computer running some type of internet sharing program. My experience with programs that run on a pc are either not as easy to setup, or do not work as well as a linksys type device. View the diagrams and descriptions below to match your setup.
Dhcp:
Dhcp is used to automaticly assign computers or other devices ip address information that it will need to communicate on the network. If your a newbie, then I would use this option, it will make things much easier. I believe that Linksys by default will do this. So, if your computer’s netowork card is set to automaticly obtain an ip address:
Then as soon as you plug your computer into a numbered port on the Linksys, then it will pull an ip address, and you will be able to communicate with it by typing “http://192.168.1.1″ into your web browser and putting in the default password of “admin” no username.
Basic pc hookup, showing that you need a crossover cable to accomplish this.
PC to PC via. hub connection, straight through cables only are needed.
Hooking up 2 pc’s to the internet via. a Linksys router. Notice: you must have an ip address that is on the same subnet as the Linksys in order to communicate with it. See the image below for example. the first 3 sets of numbers in an ip address have to be the same on all devices and the last number has to be between 1 and 254. NOTE: If you are using xboxconnect to play online, you must put your computer in the DMZ or forward port 8602 tcp and udp to the computer running xboxconnect.
Hooking up the xbox and more info. about using the Linksys. All cables are straight through, the modem is hooked to the wan port of the linksys, all other devices are hooked to the numbered swithch ports, the lan port on the Linksys is not used in this illustration.
If you have any questions, or comments, just post a comment below. Good luck,
Thanks,
-Brian
