[MLB-WIRELESS] FW: Re: Backbone links use IBSS(ad hoc) and access points use BSS (infras tructure) was: Best PCMCIA AP (prism) cards?

Sat Jan 12 08:29:43 EST 2002

Good thread from seattlewireless on why AP's aren't good for the backbone...

-D

Original Message:
-----------------
From: Kenneth Caruso ken at ipl31.net
Date: Fri, 11 Jan 2002 13:00:25 -0800 (PST)
To: dev at seattlewireless.net
Subject: Re: Backbone links use IBSS(ad hoc) and access points use BSS (infras
 tructure) was: Best PCMCIA AP (prism) cards?

Ok here is one main reason, in BSS mode all traffic has to go through the
AP. If A can see B and C can see A, if B is the BSS device that A is
associated too then C cannot talk to A directly becuase A is a BSS client
to B. The idea is that if backbone is in IBSS then you can do direct
links. 

    A---------B
    |
    |
    |
    |
    C

In the above scenario B is a BSS AP, C can see A but it cant see B. Unless
A puts up and additional Interface in IBSS mode or an additional AP, then
C will not be able to link. 

If A B and C are all in IBSS then C can link to A which can then route to
B etc...

Make sense?

Ken Caruso
kenc at seattlewireless.net
http://ken.ipl31.net

"when in doubt tell the truth" -Mark Twain

On Fri, 11 Jan 2002, Richard Lotz wrote:

> I believe the goal is to stanrdaize the backbone links such that if the
> backbone between A and B goes down, and A used B to talk to D then A could
> simply redirect their antenna to C whould can also see D.
> 
>   B----D                       B----D
>  /     | could easily become        |
> A      C                     A------C
> 
> If the need arrised, from lost of LOS or if B was unavailble or down.  If
> one side had an Omni and was operating in BSS mode then you would have to
> match your side to what the other node supported.  (what if you were seutp
> as an omni and the node you wanted to connect to was as well?).
> 
> Not to mention that its probably a good idea to segment our BB traffic
> from our client traffic, there's no reason to kill an entire node (and
> there for any nodes that connect to it) just become of some luser cient
> connected to their AP.
> 
> Of course, no one is saying that it can't be setup other ways, but this
> might be ideal when considering future network buildout.
> 
> -richard
> 
> On Fri, 11 Jan 2002, Chuck Simmons wrote:
> 
> > Is there a reason why backbone links use iBSS(ad-hoc)?  It seems like most
> > point to point links will consist of a omni on one side and a directional on
> > the other.  If all Omni antenna equipped nodes were operated in
> > BSS(infrastructure) they could serve clients nearby as well as the
> > downstream connection.  Yes I know that clients could be in iBSS and connect
> > up to the PtP link but is'nt it the expectation that clients will normally
> > use BSS?  Why force clients to switch modes depending what node they are
> > near.
> >
> > -Chuck
> >
> > -----Original Message-----
> > From: mattw at seattlewireless.net [mailto:mattw at seattlewireless.net]
> > Sent: Friday, January 11, 2002 2:45 AM
> > To: dev at seattlewireless.net; micah at colltech.com
> > Cc: Richard Lotz
> > Subject: Re: Best PCMCIA AP (prism) cards?
> >
> >
> >
> >
> > > And finally, a clarification that I can't seem to de-cloud. I am putting
> > > together a seattle wireless node, on a linux laptop that will sit on top
> > of
> > > my roof, with an antenna. Having BSS/Ap/Managed mode is going to be a
> > > necessity to be useful to the network, right? Clients can just war drive
> > > past my place, pick a signal, stop at the stopsign, dhcp an address from
> > me
> > > and be reading slashdot. If I were to use my Orinoco card, which only has
> > > IBSS/Ad-Hoc they would not be able to do this?
> > >
> >
> > It's two tiers.
> >
> > Backbone links will use iBSS point to point links.
> >
> > Access points (which clients connect to) will use BSS
> >
> > If you want someone to be able to read slashdot off of your dhcp, you will
> > have to have an internet gateway available locally. otherwise they will
> > have to connect to a dual homed box via VPN over the SWN.
> >
> > > Thanks!
> > >
> > > Micah
> > >
> > >
> > >
> > > On Thu, 10 Jan 2002, Richard Lotz wrote:
> > >
> > > > Hi again Micah :)
> > > >
> > > > I think you'll find that the Zcomax are one of the better prism2 cards
> > > > our there, far better than your average d-link or linksys.  They are one
> > > > of the few prism2 cards that have an external antenna connector and
> > their
> > > > receive sensitivity is nearly that of the Orinoco / Cisco.  I think
> > > > you'll find some more details from the dev at seattlewireless.net archives,
> > > > and probably even more in personalteco's.
> > > >
> > > > I believe that there is also a model of 3com that uses the prisim2
> > chipset
> > > > and also has external connectors, I don't know if anyone ever figured
> > out
> > > > what they were though...maybe reverse mmcx?
> > > >
> > > > Again, all of this is _only_ necessary if you want a card that will
> > > > support the BSS/Ap/Managed mode opposed to IBSS/Ad-Hoc.  Having BSS
> > means
> > > > that client configuration will be easier and should help you avoid any
> > > > incompatibilities with ad-hoc mode between different cards and even
> > > > different firmware.
> > > >
> > > > -richard
> > > >
> > > >
> > > > On Thu, 10 Jan 2002, Micah Anderson wrote:
> > > >
> > > > > I'm setting up a clunker laptop with linux and am trying to find the
> > best
> > > > > pcmcia AP (that can do BSS/Managed I assume) card that has an antenna
> > jack.
> > > > > I've heard the Zcomax (?) cards are pretty decent, and there is a list
> > of
> > > > > them at http://www.personaltelco.net/index.cgi/Prism2Card but anyone
> > have
> > > > > any opinions on which ones are better, or have drivers for linux? I
> > assume I
> > > > > can't use my Orinoco silver...
> > > > >
> > > > > Thanks, as soon as I get this straightened out I'll have a node up :)
> > > > >
> > > > > Micah
> > > > >
> > > >
> > >
> > > --
> > > Micah Anderson
> > > Collective Technologies
> > > www.colltech.com
> > >
> > > "To be and not to do is not to be at all"
> > >
> >
> 
> 

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