Re: [Autoconf] aspects of multi-hop wireless communication

Alexandru Petrescu <alexandru.petrescu@gmail.com> Fri, 19 December 2008 20:04 UTC

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Date: Fri, 19 Dec 2008 21:04:27 +0100
From: Alexandru Petrescu <alexandru.petrescu@gmail.com>
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To: Teco Boot <teco@inf-net.nl>
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Subject: Re: [Autoconf] aspects of multi-hop wireless communication
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Teco Boot wrote:
> Try it, and you will see it will fail.
> OK, you can modify the code if you have a C compiler nearby, and some
> sources to modify.

I'm not meaning to modify any code.  It's existing software doing 
bridging between two interfaces as it always did.

> But that is no longer wifi.

Well, it's two 802.11a/b interfaces, running as before.  I could put 
both interfaces in ad-hoc mode with iwconfig.  There's probably a 
misunderstanding between what the IEEE standard documents mean by 
"ad-hoc" and what iwconfig and related implementations mean by "ad-hoc" 
but I'm sure it works, by experience.

Or I could set up both to act as access points, it's the same.  (the 
only visible difference  between AP mode and ad-hoc modes in 
implementation is the MAC address of the essid... in AP mode it's the 
real MAC address of the interface doing AP, in ad-hoc mode it's some 
random 48bit).  The resolution between this 48bit number and essid ascii 
name is done by 802.11 link-layer exchanges (probe req/reply IIRC).

> You could enable routing, and you are done!

Why doing routing when I could do bridging, simpler, widely available 
software.

> Play a little with it, and check your (false) assumptions.

I'm not sure which assumption you think I made false?  The fact that I 
could build a bridge with brctl and two wifi interfaces?

Alex


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