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Appendix B - Wireless Technology
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MVP-8400i 8.4" Modero® ViewPoint® Touch Panel with Intercom
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-If 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 you
can expect to obtain 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 shorter in 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.
As an example: Imagine a panel connected to 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 determining which network interface (wired or
wireless) that will be used is dependent on the gateway.
Wireless Access Points are the cornerstone of any wireless network. A Wireless Access Point acts as a bridge
between a wired and wireless network. It aggregates the traffic from all the wireless clients and forwards it
down the network to the switch or router.
One Wireless Access Point may be all you need. However, you could need more Wireless Access Points
depending on either how large your installation is, how it is laid out, and how it is constructed.
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 you use, it's crucial to use identical settings (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 doesn't, they won't be able to talk to each other.
Although the calculations required to encrypt data with WEP can impact the performance of your wireless
network, it's generally seen only when running benchmarks, and not large enough to be noticeable in the
course of normal network usage.
Terminology
802.1x
IEEE 802.1x is an IEEE standard that is built on the Internet standard EAP (Extensible Authentication
Protocol). 802.1x is a standard for passing EAP messages over either a wired or wireless LAN.
Additionally, 802.1x is also responsible for communicating the method with which WAPs and wireless
users can share and change encryption keys. This continuous key change helps resolve any major security
vulnerabilities native to WEP.
AES