Bob,
I'm not involved with KarlNet at all, nor with any development efforts
at KarlNet. But, seeing as how I am at least fairly qualified in the
"networking guy" arena, I thought I'd take a stab at answering your
question.
First, we need to take a look at what Layer 2 switching is like in the
absence of VLANs. Layer 2 switches automatically limit the size of
your collision domains by eliminating internal collisions. By using a
variety of queuing techniques, the switch guarantees that frames
passing through the switch will not collide with one another.
Another benefit of Layer 2 switches is the idea of multiple concurrent
conversations. A switch only floods unicast frames out the port to
which it knows the destination MAC address is connected. This means
that the only node that "hears" traffic is the node for which that
traffic is destined. This leaves other nodes on other ports free to
receive unicast traffic destined for them at the same time.
For networks to work, however, the default behavior of a switch is to
flood every Layer 2 broadcast frame out each of its ports. The same
thing happens when the switch has to relay traffic to a destination,
the MAC address of which the switch has not learned. In very large
networks that are segmented by bridges (and a switch is just a bridge
with more ports), and not by Layer 3 routers, this broadcast and
unknown-destination traffic can bring the entire network to its knees.
The concept of VLANs in Layer 2 switches is to add another layer of
abstraction, to be able to limit the size of your broadcast domains.
By identifying members of a VLAN, you can limit the flooding of
broadcast and unknown-destination traffic to the ports associated with
that VLAN. This can happen across the entire network, through
multiple switches; traffic will only be sent where VLAN members are
found.
What benefit can be gained from VLANs in a wireless environment? The
answer depends on your topology. If you are using the routing
functionality provided by KarlNet, then the answer is no benefit. You
are already segmenting your network at Layer 3, no Layer 2 broadcasts
will propagate through your routers.
If, however, you are bridging everything in your wireless network, the
benefits of VLANs can be pretty significant. You can limit broadcasts
so that they will not leave the segment serviced by a single AP,
instead of propagating across your entire network. You might be
surprised by the amount of bandwidth saved by doing this.
TurboCell already addresses the problem of collision domain size with
its intelligent base stations and their polling MAC. So long as there
is only one radio interface through which traffic can be received from
client nodes, I can't imagine any way to replicate true "multiple
concurrent conversations" behavior in a wireless bridge. Adding VLANs
to KarlNet software would add serious value for those who want to
limit their broadcast domains while staying out of Layer 3 routing.
I hope that, as long-winded as this was, it answered your question.
Please let me know if you still have questions -- if I haven't scared
you away or put you to sleep by now. :)
-Brian
____________________________________________________________
Brian H. Oak CISSP?CCDP CCNP CCA NNCAS Datawav-IS, LLC
Principal Engineer? ?? 109 N. Arthur Ave., Ste. 301
(208) 232-6860???????????????? Pocatello, ID? 83204
(208) 232-0185?fax???????????? ?? ??brian@infosystems1.com
-----Original Message-----
From: karlnet-bounces@WISPNotes.com
[mailto:karlnet-bounces@WISPNotes.com]On Behalf Of Bob Hrbek
Sent: Monday, February 03, 2003 14:50
To: Karlnet Mailing List
Subject: Re: [Karlnet] License-it site
can somebody explain to me the point of wireless vlans? I'm not a
huge
networking guy but my understanding of vlan is a virtual lan in a
switching
environment. The purpose being to segment the switch to create
multiple
logical switches. I know of two ways to divide the switch, (MAC based
and
Port based) but how would this benefit a wireless network? Your AP
cannot
be a controlled medium unless you are talking about making it so only
CPEA
and CPEB and the AP can talk to each other, etc. (hmm)
Just wondering what your take on it was.
-bob
----- Original Message -----
From: "Dan Metcalf" <dan.metcalf@wbsysnet.com>
To: "'Karlnet Mailing List'" <karlnet@WISPNotes.com>
Sent: Monday, February 03, 2003 3:41 PM
Subject: RE: [Karlnet] License-it site
> Kevin,
>
> How soon can we expect the "auto-roam" and vlan updates?
>
> Dan Metcalf
> Wireless Broadband Systems
> http://www.wbsysnet.com/
> 781-577-2780
> dan.metcalf@wbsysnet.com
>
>
> > -----Original Message-----
> > From: karlnet-bounces@WISPNotes.com
> [mailto:karlnet-bounces@WISPNotes.com]
> > On Behalf Of Kevin Knuth
> > Sent: Sunday, February 02, 2003 10:16 PM
> > To: Karlnet Mailing List
> > Subject: RE: [Karlnet] License-it site
> >
> > I will forward this to the appropriate people!
> >
> > Kevin
> >
> > -----Original Message-----
> > From: karlnet-bounces@WISPNotes.com
> > [mailto:karlnet-bounces@WISPNotes.com]On Behalf Of andrew
> > Sent: Saturday, February 01, 2003 9:44 PM
> > To: Karlnet Mailing List
> > Subject: RE: [Karlnet] License-it site
> >
> >
> > kewl, since you are making all these changes, would it be
possible
> to
> > have a page that returns a tab delimited file of all the licenses
that
> you
> > have on your account? They want me to write a script here to
track
> all
> > our licenses and match them to stuff that is in use. If there was
a
> way
> > to
> > get that from the site in an easy to parse way rather than having
to
> > script
> > out the HTML that would be really handy!
> >
> > thanks!
> > andrew
> >
> > At 12:18 PM 1/31/2003, you wrote:
> > >As Karlnet moves to a distribution model we will continue making
> changes
> > to
> > >the site.
> > >
> > >One of those improvements will allow you to combine your
accounts.
> > >
> > >Kevin
> >
> > --
> > andrew
> >
> >
>
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