"Frank Taylor, Jr." <(E-Mail Removed)> wrote in message news:<1YWdnbnvevTp7n-(E-Mail Removed)>...
> John,
>
> If you want to set up a large wireless network where a user can roam from
> one access point to another then they should all be using the same ssid but
> different channels.
>
> Think of the ssid as being the network address. All of the AP's connect to
> the same network so they should be using the same network address. You do
> not want the signals from each AP to interfere with the others which is why
> they need to be on different channels. Assuming that you are using 802.11b,
> use channels 1, 6 and 11 for any three AP's in the same area to ensure that
> there is no interference as a result of the overlaping channels.
>
> Good luck
>
> Frank Taylor, Jr.
> BSMET/MSM/MCNE/MCNI/CCNA/CCDA/CCNP/CWNA/MCP/A+/CIP/CNS
> Consulting Partner - Zen Technology, Inc.
> Authorized Cisco Reseller
> Authorized Novell Partner
> (E-Mail Removed)
> KG4QZZ - HAM Radio
> Vessel Safety Chairman - Atlanta Sail and Power Squadron
> Skipper of Cruiser "Miss Vonn" Aqualand Marina Slip N-27
>
>
> Remember: In order to excel at something, you must first learn to enjoy
> doing it badly.
> "John" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
> > Looking into a wireless solution for a mobile force. this will
> > incorporate access points as well as mobile dialup devices.
> >
> > We've elimimnated problems with multiple gateways and such for roaming
> > from an access point to switching over to the dialup and back again,
> > but I have a question specifically regarding access point
> > configurations.
> >
> > I've seen in here that for roaming in an access point environment,
> > someone once suggested that the access points be configured on
> > different channels, same SSID, so that the wireless device would roam
> > from one point to another when it moved out of range of the first
> > device and into the range of the second. This was said to allow
> > continued networking with no interruption in service for the end user.
> >
> > Other sources I've looked into also said to not have multiple access
> > points nearby using the same set up (i.e. same SSID, same channel,
> > etc).
> >
> > one of the engineers here took our three access points and did some
> > testing. he did the "all set the same" setting and the wireless
> > device had no problem with the setup, and they didn't appear to
> > interfere with each other. He could then unplug them one at a time
> > randomly and have the wireless device keep working, as long as one was
> > plugged in at any given moment.
> >
> > I'm just trying to understand the setup of multiple access points like
> > this, and why or why not to do certain things, like having all on the
> > same channel using the same SSID. We've seen here that that setup
> > works, but we don't know what the impact is, what drawbacks there are.
> >
> > Can someone give some pros / cons for setting them up all the same, or
> > as the original article I found said, setting them up with the same
> > SSID but giving different channels?
> >
> > What really *is* the optimal setting for roaming users? And in a
> > multi-subnet setting, what are the recommendations so that if someone
> > on subnet A, say, with a DHCP enabled device, gets an address on
> > subnet B when he moves to a different floor while wandering around and
> > comes into range of an access point on a different subnet?
> >
> > Any good books or white papers or articles someone can point me to
> > that will address these specific issues?
> >
> > Thanks for any info!
> >
> > John
> >
I agree with Frank's recommendations because I know from experience
that it works. A couple of years back, I installed a 60+ AP solution
in a large corporate HQ and did exactly that - i.e all APs on the same
SSID, but on different channels (we actually used 1, 7, 13) in
adjacent areas. In large open-plan offices, 2 APs (on different
channels) were installed to give good signal coverage in all parts of
the office.
One of the tests we did was to walk around with a laptop that was
sending continuous pings to a server to see if any were dropped as we
associated with a different AP. The results were excellent with very
few pings being missed.
All the APs were connected to the same VLAN (Class C subnet dedicated
to WLAN users) because there were enough IP addresses to cater for the
number of users who were issued with wireless cards for their laptops.
Of course, if you are expecting to have a very large number of WLAN
users, this would need to be implemented differently.
Just a couple of other points to consider regarding security.
1. Signal Leakage - would this be a problem for you?
The first pilot install used omni-directional antennae (the "rubber
duck" type) set at a transmit power of 30mw. This allowed us to
actually logon to the network 250m across the car park. This was
obviously a potential problem and the design was reviewed. The final
installation used APs, set to transmit at 1mw with directional patch
antennae, which were located on the outside walls facing inwards. This
doubled the original 30+ APs required, but the ability to logon was
limited to within 5m of the building.
2. LEAP.
We used LEAP to authenticate and pointed the ACS server to the Windows
domain database, changing the WEP key every 10 minutes.
In a subsequent security survey conducted by an 3rd party consultancy
(using Airopeek wireless sniffers, high gain antennae etc.), they
concluded that the installation was about as secure as it could be at
that time apart from the use of VPN clients on the laptops.
Hope thats of some help.
Pete
Similar Threads
Linear Mode
