davidodimegwu@hotmail.com hath wroth:
>Thanks liebermann, speed and security are two sore points for my need
>of a "wireless switch".
Here's an article on the current state of the art for wireless
security:
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http://www.itarchitect.com/shared/ar...leId=180201637
If you're genuinely concerned about security, I suggest you adopt a
holistic approach that looks at the security for the entire system
which includes physical access, denial of service, and sniffing the
wired part of the network.
Speed? What are your expectations for thruput? Note that wireless is
a shared media system. Only one transmitter for a given system can be
on the air at time in a given air space. It's like one big party line
that includes other users on the channels. This is the real problem
with large systems. With only one xmitter on the air at a time, the
total available bandwidth is divided by the number of xmitters.
Speed is also a function of distance. The farther you go, the weaker
the signal, the more the noise, and therefore the slower the data rate
necessary to retain some semblance of a decent BER (bit error rate).
The standard reference for receiver sensitivity is based on a BER of 1
hiccup every 10^5 bits (or 10^6 in some tests) or about 10% PER
(packet error rate). See the table at:
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http://wireless.wikia.com/wiki/Wi-Fi#Link_Calculations
A 6dB increase in fade margin or SOM is good for a doubling in range.
>I want to localise the hosts for security and
>management purposes so that they can easily be monitored, that is why i
>want a switch and not a wireless router.
That's good. Just realize that most such wireless switches are not
intended to operate as mesh networks with repeaters and such. Every
access point requires a CAT5 backhaul to the central switch. If this
system is intended to replace a previously functional wired system,
you just put the wires back.
>is there a site for a cheap
>wireless switch?
Not that I know about. They tend to be horrifically expensive because
there are few customers that really need a wireless switch. The price
scales nicely with the associated access points as these are produced
in substantial quantities and are often just adaptations of existing
commodity wireless access points. However, the central switch is
pricey. The inability to mix and match wireless access point vendors
on a wireless switch system locks the customer into a single
proprietary vendor. This closed model tends to be pricey and often
predatory.
Vendor list:
Symbol
Airespace (Cisco)
Aruba (HP)
Entrasys
Xirrus
Meru Networks
Foundry Networks
Trapeze (3Com)
Chantry (Siemens)
http://www.arubanetworks.com http://www.symbol.com/products/wireless/wireless.html http://www.airespace.com http://www.chantrynetworks.com http://www.trapezenetworks.com http://www.merunetworks.com
(etc)
>the buys are being self-financed, maybe when the
>business grows, i can go for the expensive ones on the market. A
>reliable second-hand is not a problem as long as there is a warranty
>backing it.
I would advise that you rethink your strategy. The problem with
buying into proprietary systems is that they do not survive
obsolescence very gracefully. Visualize buying a wireless switch
system perhaps in 2002 when such systems were initially proposed. 4
years later, you would be stuck with an 802.11b only system, possibly
with only WEP. The alternative would be wholesale replacement of the
access points with 802.11g or MIMO capable radios. If you have
confidence in your vendors ability to provide feature updates without
also requiring hardware upgrades, then perhaps proprietary systems are
tolerable. However, if you're planning on keeping up with the state
of the art, you'll need to consider obsolescence, upgrades, and
expansion costs.
>thanks. I will be very happy if i do get a response.
Hint: Without numeric specifics, I can only supply general answers.
Your posting IP of 196.3.62.3 resolves to Nitel Networks in Nigeria.
Are you sure you have the funds available to utilize a wireless
switch?
Your proposed topology sounds more like an attempt to connect separate
buildings to each other. This is NOT an appropriate use of a wireless
switch. Wireless switches are best deployed where you need to connect
a large number of users (laptops) to a central WLAN and where the high
initial cost is offset by the relative ease of management and
monitoring. Schools, large office buildings, government offices,
"campus" like areas, and some municipal networks are good candidates.
Point to multipoint connectivity between buildings is NOT.
--
Jeff Liebermann
jeffl@comix.santa-cruz.ca.us
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Cheap wireless switch? 
Linear Mode
