a bunch of wireless questions

these questions looks dumb but i need your help, i read so many documents about wireless but didn't comprehend some things.
please help me.

i know wireless is the status of wire-less and has some kind of
standards 802.11b/a/g and between them 802.11a is better than
others.But what about the communication with wireless?
for example access points , adsl wireless modems etc.

i mix them into each other. i read some documents about wireless
but i still didn't understand some things.

access point : i have a notebook and trying to communicate with
another , when do i need an access point ? and do I have to buy them or what should i do ? what is the difference between wlan access point
and wireless adsl modem also has access point feature?

and i read things for example acces points connects into ethernet (wired)lan
and provides internet , i didn't understand this because we use wireless
so why should we connect wired lan?

without an access point what is the disadvantage for this?
how many user can communicate without an ap?

if i can connect an existing wireless lan why should i build a new one?

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Comments

james_

Wireless A is not better than the rest, just different, in the fact that it operates in the 5GHz range. It is mostly used for point to point connections and has a further range. Wireless B and G are more mainstream, operating in the 2.4GHz range and have a wider broadcast, but not the same ditsance. Wireless G is just as fast as A, plus it is backwards compatible with B.

You can operate a point-to-point wireless connection, ie a connection between 2 laptops through Ad-Hoc mode, no need for an access point there. Most often you operate in infrastructure mode, ie. you stick a wireless access point in the most efficent spot in the office that connects to your standard wired internet feed, and all clients with wireless cards can then connect to that access point. The wireless internet has to get its feed from somewheere right? The internet just doesn't exist in the air.

I would say, although am not sure, as many people as you want can connect to a WAP, bear in mind bandwidth would suffer though, as it would be shared between all users.

Hope this answers some of your questions.[/b]

drainey

First let's talk about the access point. This is a device that connects a wired network to a wireless network. Or putting it another way it gives a person using wireless "access" to the wired network. Thus the name access point. As for whether or not you need one, that depends on your needs.

If you have a wired network and want to be able to connect to it via wireless, (referred to as infrastructure mode) then yes you need one and yes you'd have to buy one. If you simply want to connect some wireless capable devices (say two laptops) together (referred to as ad-hoc mode) then you don't need one. The ad-hoc mode usually will only support about 10 devices.

As for building a new one versus connecting to an existing one, that also depends on your situation. If you are talking about a home network and the existing wireless is someone else AP then I'd recommend buying your own AP. First depending on your local laws you can be doing something illegal by connecting to someone elses network. Second your data will be passing through someone elses network making it easier for them to sniff it (possibly resulting in loss of data or identity). Third you can secure your own network and eliminate any unwanted traffic.

Hope this helps. If you want to learn more I'd recommend getting the study guide for the CWNA from www.cwnp.com. It has an incredible amount of easy to understand information.

Best of luck.

Rearden

I can also add that Cisco access points are often used in Lightweight mode in which you do not configure access points individually but a central controller. The controller then configures all access points. It's very useful for large deployments.

There are also solutions that let you add authentication through Active Directory and such.

kobem

thanks for your help but i have got another questions

for ex. i am at school and have laptop and also my friends have.
and in cantina i want to connect to the internet with a wireless way
so do i have to buy an AP for this ?

and another one : i am at school again and in library there is a computer
and i connect to the internet with a wireless way , do i need an AP?

kobem

drainey wrote:

If you have a wired network and want to be able to connect to it via wireless, (referred to as infrastructure mode) then yes you need one and yes you'd have to buy one.

what does this mean ?

Best of luck.

james_

If you are at school, and you have a laptop, and want to get onto the schools wireless internet, you would need to be in range of a WAP. You could buy a WAP yes, but that WAP would still have to be "wired" into the schools wired network. Then the WAP would connect wirelessly to your Laptop. Bear in mind the security features of Wireless, just having a WAP in range, doesn't mean you can access it, there may be security features in place - which include WEP and MAC Filtering, and more recently WPA, that prevent just anyone from accessing the wireless network.

If you are at school and using a computer to "connect in a wireless way", then yes there has to be a WAP somewhere that is physically wired into the network, additionally the computer would need to have a wirless NIC, or external Wireless device (like a wireless USB, which is essentially the same as an internal wireless NIC, just looks different and is external) that could communicate with the WAP, the PC cannot connect to the WAP with a standard NIC.

Laptops pretty much as standard come with both a Wireless NIC and a standard LAN NIC. Desktops usually only come with a standard LAN NIC.

Hope this helps!

kobem

james_ wrote:

If you are at school and using a computer to "connect in a wireless way", then yes there has to be a WAP somewhere that is physically wired into the network, additionally the computer would need to have a wirless NIC,

so when i connect on computer with wireless way , isn't enough the wireless NIC on PC i used alone?

shortly except peer to peer communication max 10 laptops , we have to use an AP right?

Hope this helps!

james_

"so when i connect on computer with wireless way , isn't enough the wireless NIC on PC i used alone?"

Providing the NIC is wireless and there is a WAP in range, you can connect wirelessly, Just having a wireless NIC in a computer won't get you onto a wireless network alone, it must have a WAP to connect to, or indeed through Ad-Hoc mode connecting to another PCs wireless NIC - but this will obviously only give you pc-to-pc connection, not network connection

"shortly except peer to peer communication max 10 laptops , we have to use an AP right?"

I am not sure the limit of point to point connections that can be made, but generally yes, if you are using more than a few wireless connections, you will usually see a WAP in play

kobem

james_ wrote:

Providing the NIC is wireless and there is a WAP in range, you can connect wirelessly, Just having a wireless NIC in a computer won't get you onto a wireless network alone, it must have a WAP to connect to, or indeed through Ad-Hoc mode connecting to another PCs wireless NIC - but this will obviously only give you pc-to-pc connection, not network connection

but i have a girlfriend and she has laptop and she also has wireless usb adapter for plug and connects to the internet on her laptop at her home so where is
AP?

james_

A WAP can generate a signal maybe 250-300ft. I have a wireless setup at home, and when I look at all the wireless connections, there are at least 3 other wireless networks in range of my Linksys USB wireless adapter, I cannot connect to any of them because they are secured, but they are there. If they were not secured, then I could easily connect to any one of them and start using other people's bandwidth

kobem

so nearby there is an AP?

james_

Exactly. Bear in mind also, the WAP can be built into the router, my Linksys setup came with a wireless router and wireless USB adapter, essentially it functions both as a router and a WAP.