Wireless Networking and WiFi

Each subinterface should be configured with its own IP address, subnet mask, and unique VLAN assignment.

The physical interface of the router must be connected to a trunk link on the adjacent switch.

Network IDA network ID refers to a part of a TCP/IP address that is used to identify the subnet that a host may be on. The subnet that the computer is on is determined by the netmask and IP address of the computer. This subnet address is the same as the network ID and is the beginning part of the computers IP address.

When the netmask is setup, it is a number where some of the most significant bits have a 1's value and the rest have values of 0. The most significant part of the netmask with bits set to 1's specifies the network address, and the lower part of the address will specify the host address.

The part of the IP address that matches the part of the netmask where the bits are set to ones determines the network ID.

It's not "illegal" if your router is configured to grant them access to your network.

The law only prohibits "unauthorized access of a computer network". When someone uses their computer to request access, and your router grants access with no password, then their access of your network is authorized. I always configure my routers to share my connection with neighbors and visitors (in a secure way, of course).

If you enable WEP encryption, and they crack the encryption in order to access it, then it's illegal, because their access was unauthorized. But this only makes it illegal for them, it doesn't actually stop them. WEP is very easy to crack, and basically useless. Disabling SSID broadcast is also useless.

While WEP will certainly put you a step ahead of no security at all, if the neighbor is determined to use your wireless network they can break WEP encryption pretty simply using aircrack, a freely available tool. To really stop them, you need to use the stronger encryption offered by WPA or WPA2, which is available on all newer wireless routers. Then it is both illegal and difficult (if not impossible) for them to crack.

When enabling encryption, use a passphrase. It is MUCH easier to set up on other computers than it is to type 42 randomly chosen letters and numbers!

With the SSID changed from the default, broadcast of that name disabled and with the encryption set at 128, it will practically be impossible for your neighbor to get online by using yourrouter.

The neighbor may SEE your wireless network but will not be able to access it without the correct passphrase.

If you enable WPA you will have the option of using TKIP or AES encryption. Choose the stronger AES encryption if your router and client systems will support it. Although most neighbors will not be sophisticated to take advantage of it, there is an identified vulnerability in the TKIP algorithm for WPA for which exploits are available. You are better off using the AES encryption.,

Its very easy. Plan A is based on the fact that all laptops these days come with a wireless adapter built in. All you need to do is to switch on the power and your laptop will begin scanning for an available Wi-Fi hot spot (a wireless signal broadcaster). Try it out by taking your laptop to the nearest public library or Starbucks. Elsewhere, most Wi-Fi hot spots are protected by a password without which you won't be able to use them for connecting to the internet. So the thing to do is to install your own Wi-Fi hotspot, which means buying (for about $60) a Wi-Fi capable router and hooking it into the DSL or cable modem that is itself hooked to your internet cable. (In fact, you can even plug this Wi-Fi router into an existing, wired router that you might already have - it plugs in just as a computer would and with the same kind of cable and, apart from broadcasting a Wi-Fi signal, it also has slots for accommodating standard wired connections for additional wired computers.) This Wi-Fi capable router will then broadcast a wireless signal that your laptop will be able to pick up from basically anywhere in a radius of about 100 ft without any need for a wired connection between the laptop and the wireless router, even through walls and ceilings. But keep in mind that any number of laptops can do likewise, including those of your neighbors. So, others might and definitely will use your Wi-Fi connection as well unless you lock it by means of a password (Windows XP will generate a password for use with your Wi-Fi router.) It's good policy to use a password given that your ISP will crack down on you if it notices heavy use on your internet connection, as would happen if your neighbors started downloading movies all day long through your connection. Besides, there is also the risk that dishonest people could connect to your PC and steal your passwords and such.

Plan B is for a desktop or the odd laptop that has no wireless adapter. You can buy a wireless adapter for either for about $30 and slip it into an Express Slot on your laptop or any open slot in your desktop and then use Plan A as above.

Plan C is in case you're on the go with your laptop all day long, in which case you should look into buying what's called a Mi-Fi, that's a gadget like a USB stick that you can keep in your pocket or purse and that amounts to a specialized cell phone and that does one thing only: it's permanently connected to your ISP (such as Sprint or Verizon) and permanently broadcasts a wireless signal that up to 6 laptops (or wireless enabled gadgets like Skype or smart-phones) within 50 ft around you can use to connect to the internet provided you give them your password. So you can use a Mi-Fi on a plane, at the beach, or wherever you could use a cell phone. It's like carrying your own Wi-Fi hot spot with you everywhere you want. It costs around $100 for the gadget which comes with subscription plans whereby you pay by the month or only on those days when you expect to use it.

You would use a network cable to connect a computer to a network. The type of cable and its electrical, possibly optical, and mechanical attributes depend on the network's pysical layer.

Networks use a variety of fiber optic cables, coaxial cables, single twisted-pairs, double and quadruple twisted-pair cables. Other forms exist, including those not requireing a dedicated cable (such as some devices designed for networking over power line), or not requireing a cable at all (such as devices designed for networking over radio frequency connections).