WiFi Basics - Something alot of people want to know

[UncleRonin]

Alright then. We all know how about WiFi and how wonderful it is but there's plenty of stuff we don't know about it. The main purpose of this thread is that I was hoping that folks in the know could explain a few basic things about it.

Wireless LAN's. Okay, so you have a laptop or PDA and you connect to a wireless LAN (I assume that a WLAN is best setup using DHCP?). This WLAN will use TCP/IP as its standard protocol? Now, say for example that you want to write a chat app so that folks on the WLAN can communicate through WiFi as though it is a normal LAN. Am I right in saying that this will behave in exactly the same way as with a normal LAN - with TCPClients and TCPListeners? So as long as there is a server app running (on the WLAN) which handles the connections all will be well.

WLAN server. Say you have a bunch of access points and want to set up a WLAN. How would you go about doing this? As far as I know, the AP's get given an IP on the normal LAN and they create a Virtual LAN? I know that for positioning engines and things like that you have to have the engine server running on a PC somewhere but what sort of app or server governs the WLAN itself?

Probably the most important question of all: How do you communicate from a PC on the LAN to a PC on the WLAN? Will you use an intermediate PC? So if you want to use this chat program, the PC on the LAN will send a message to the server (connected to both the LAN and WLAN - is this possible?) which will then communicate that message to the target device on the WLAN.

Sorry if I haven't explained myself very well. The reason I am asking is because I need to set up a WLAN and then use it for my Honours project. (The chat app is an example!) I am terrible at search engines and the folks here at VBdotnetforums have always been lank helpful in the past so I though I'd ask here first. If anyone can help me out or point me in the right direction I would really appreciate it. It's kinda a matter of my Honours project's life or death!

 

[Blake81]

Using your chat app as an example, you don't even need to think about the WLAN being there, for those purposes. I've got two PCs here at home connected to a firewall/router, with a wireless access point also plugged into one of the ports in the firewall/router so my laptop can go wireless. The laptop can "see" the two PCs just fine and the wireless part of it is transparent to me as far as anything I want to do over the network. Yes, the AP provides the laptop with an IP address, but it's still on the same workgroup as the two PCs, so if I get on the laptop and go to My Network Places, I can see the two PCs.

 

[TechGnome]

Technically speaking, wireless LANS do not use TCP/IP for the wireless part of the protocol. That is actualy handled by the 801.11 [g/b/...] protocol. The 801 specifications dictate how the components of a wireless network communicate w/ each other.

As for IP assignment, it can be done one of two ways. Most routers come with the ability to act as a DHCP Server and assign IPs to any computer connected to the network. This is how I have it at home. I 6told my router to act as the DHCP for my home network, then gave it a very narrow range of IPs for assignment. The other possibility is static IP assignment. The router turns off the DHCP and each machine is then responsible for getting an IP (this means an admin has to go around to each machine to set the IP address by hand.)

Now, that's all for a very simple home-type network where there is no server, just a bunch of PCs connected on a network. For larger sized LANS (wireless or not) it requires a Primary Domain Controler server. This server (and it is a real server, with something like Windows Server installed, not just Windows) and is responsible for controlling access to the network. It's where users get setup, passwords reset, accounts locked, and will also pass out IP to other machines on the network. And that's about the extent of my knowledge of such matters.

-tg