AMX Modero MVP-5200i - Manual (Page 172)

Appendix B: Wireless Technology
164 MVP-5200i Modero Viewpoint Widescreen Touch Panel
Appendix B: Wireless Technology
Overview of Wireless Technology
802.11b/2.4 GHz and 802.11a/5 GHz are the two major WLAN standards and both operate
using radio frequency (RF) technology. Together the two standards are together called Wi-Fi
and operate in frequency bands of 2.4 GHz and 5 GHz respectively.
The 802.11b specification was the first to be finalized and reach the marketplace. The actual
throughput obtained from an 802.11b network will typically be between 4 and 5 Mbps.
Because of the higher frequency (and thus shorter wavelength) that they use, 802.11a signals
have a much tougher time penetrating solid objects like walls, floors, and ceilings. As a result,
the price for 802.11a's higher speed is not only a shorter range but also a weaker and less
consistent signal.
802.11g provides increased bandwidth at 54 Mbps. As part of the IEEE 802.11g specification,
when throughput cannot be maintained, this card will automatically switch algorithms in
order to maintain the highest spread possible at a given distance. In addition, 802.11g can also
step down to utilize 802.11b algorithms and also maintain a connection at longer distances.
IP Routing is a behavior of the wireless routing is largely dependent on the wired network
interface. Although the panel can be connected to two networks simultaneously, it may only
have one gateway. If the wired network was successfully set up and a gateway was obtained;
then the default route for all network traffic will be via the wired network. In the event that the
wired network was not configured, then the default route for all network traffic will be via the
wireless network. The wired network connection always takes priority.
Example: Imagine a panel connected to the two networks A & B. A is the wired network
and B is the wireless network. If the Master controller is on either of these networks, then
it will be reached. However if the Master controller is on a different network, C, then the
gateway determines which network interface (wired or wireless) will be used.
Wireless Access Points (WAPs) are the cornerstone of any wireless network. A WAP acts as
a bridge between a wired and wireless network. It aggregates the traffic from all wireless
clients and forwards it down the network to the switch or router. One WAP may be all that is
necessary for a standard installation. However, more WAPs may be needed, depending on the
size of the installation, its layout, and its construction.
Wireless Equivalent Privacy (WEP) Security is a method by which WLANs protect wireless
data streams. A data stream encrypted with WEP can still be intercepted or eavesdropped
upon, but the encryption makes the data unintelligible to the interloper. The strength of WEP
is measured by the length of the key used to encrypt the data. The longer the key, the harder it
is to crack.
802.11b implementations provided 64-bit and 128-bit WEP keys. This is known respectively
as 64-bit and 128-bit WEP encryption. 64-bit is generally not regarded as adequate security
protection. Both key lengths are supported by the Modero product line.
Whichever level of WEP used, using identical settings is crucial (CASE SENSITIVE)--the
key length, and the key itself-- on all devices. Only devices with common WEP settings will
be able to communicate. Similarly, if one device has WEP enabled and another does no, they
will not be able to talk to each other.
Although the calculations required to encrypt data with WEP can impact the performance of
your wireless network, this impact is generally only seen when running benchmarks, and is
not large enough to be noticeable in the course of normal network usage.