On Sat, May 18, 2002 at 08:10:27AM +0100, Shyam Kumar Mangayil wrote:

> 1. differences between ad-hoc and infrastructure mode

Is the difference between not having an access point and having an access
point.

An access point is a wireless network's bridge into another LAN, like a
physically cabled one. If you only want to have a wireless network between
two computers without linking into another network, that's ad-hoc.
"Infrastructure" suggests you've got an existing network infrastructure that
you want to use with the wireless LAN, therefore you need an access point.

> 2. "If you're in ad-hoc mode, the default (3) is correct. If you have an access point, set your port type to 1. I'm using an Apple Airport access point, so I tell the card to search for it with:
> 
> wicontrol -p 1"  :
> 
>  What is this port ? and what is access point ?

I assume (without having that manpage) that the port indicates to the software
whether it should be scanning for an access point or just broadcasting to the
ad-hoc network.

> 3.  "Then you have a network name. You can only network with hosts with the same network name, so this needs to be correct. This helps keep neighbors off your LAN, and vice versa. Since Lucent cards attach to the first network they find, such wrong connections can be a perfectly innocent error instead of a blatant attempt to steal your bandwidth. You set the network name as such:
> 
> wicontrol -n YourNameHere"
> 
> What is meant by network name ?

Just a name that you make up, if you wanted to have two wireless networks
in proximity to each other that you wanted to topologically separate you'd
give them separate names.

> 4. Most of these  setup - guidelines say that the fourth step is you can setup
> an IP address.How , suppose , I am using a WaveLAN card ?
>       wicontrol -something        , I guess .

For my Cisco PCMCIA card I use something like

ifconfig an0 inet 192.168.1.4 nwid WLAN netmask 255.255.255.0

where WLAN is the network name I want to connect to

> 5.  I am just reading howto setup a WLAN card , so this question might be silly , infact very foolish : What really is the medium in WLAN as cable is to a LAN ?

It's a high frequency radio link, about 2.4Ghz
You should also look into WEP, the wireless encryption protocol. This is the
system that's supposed to encrypt wireless traffic. So people can't just wander
past your office building and connect to your LAN with their wireless laptop
and steal your data!

> Science has taught us not believe what you have not seen , and as yet,
> I have not physically seen a WLAN , just read , so that's why I wish to ask this
> foolish question.
> Because      6.    won't questions of EMI arise in a WLAN ?

They might do, but only under extreme circumstances. Certainly wouldn't get
enough interference in an office to disrupt the signal. The main problem is
having to transmit the signal through walls etc.

> 7. Can you give me some sites from where I can see photos of WLAN cards and get into their details ?

www.cisco.com have models of cards and access points
I imagine 3com and Netgear have their own too

> 8. How much would a WLAN card cost (I am looking for free hardware so that I may get two.)

Not sure at the moment, those sites will tell you though.

> 9. If I setup a dual-homed host , is that enough for me to learn  Wireless Networking ? I can not afford two machines per se , but I am thinking in terms of "at least a dual-homed host" .

Well if you get an access point and a couple of cards, or just a couple of
cards I have to advise you get them from the same manufacturer! My first
experience with mixing vendors technologies was that the PCMCIA cards kept
losing track of the access point, or vice versa, so you had to physically
power-cycle the access point to get everything going again - very annoying!

 - Chris

--
strawberry@toth.org.uk
http://www.toth.org.uk/~strawberry