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Date:      Wed, 25 Jun 1997 18:35:59 +1000 (EST)
From:      "Daniel O'Callaghan" <danny@panda.hilink.com.au>
To:        "Rodney W. Grimes" <rgrimes@GndRsh.aac.dev.com>
Cc:        Bernie Doehner <bad@uhf.wireless.net>, freebsd-isp@FreeBSD.ORG
Subject:   Re: Wireless Services
Message-ID:  <Pine.BSF.3.91.970625182726.869h-100000@panda.hilink.com.au>
In-Reply-To: <199706220250.TAA00982@GndRsh.aac.dev.com>

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On Sat, 21 Jun 1997, Rodney W. Grimes wrote:

> The problem seems to be that the card(s) [I am running multiple cards
> in the same box] are either a) hearing each other (how can that be,
> they are on different NWID's) or b) the multicast code is sending
> the same packets out all interfaces (gated/ospf could be in error
> here, but it works just fine when I replace all the wl cards with
> de cards.)

[...snip...] 
> One other thing... these cards don't seem to be to good at Collision
> Avodiance when you have a routing type of setup (ie, you have a central
> node with 2 cards in it talking to 2 other sites and are trying to
> ftp packets (gee, maybe a stick drawing would be better:))
> 
> 
>        A/wl0 <-----> wl0/B/wl1 <-----> wl0/C
> 	       18mi              12mi
> 
> You can ftp really nice between A and B or B and C, but try to go
> from A to C and your bandwidth goes in the dump.  I worked around
> it with some realy bad kludges, there has to be a better way!

I was just talking to someone about this sort of stuff.  Apparently 
Wavelans are spread-spectrum, but they use direct-sequence SS, rather 
than frequency hopping SS.  There are just a few centre frequencies which 
can be set, and that is the only way to avoid collisions on neighbouring 
cards.  The NWID is only to code the packet so other cards will ignore it.

I was given a brochure about BreezeCom products, which *do* do frequency 
hopping SS.  <http://www.breezecom.com/>.
2195 Faraday Ave, Suite A
Carlsbad, CA 92008
1-619 431 9880

If someone could find out indicative prices for their products I'd 
appreciate it.  e.g. a single ethernet to wireless station adapter.  Code 
SA-10 or SA-10D.


Danny



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