Wireless Redundancy Technology |
| Radio interference is always a major
concern for wireless applications. In fact, the real world presents
many factors that result in less-than-perfect wireless performance,
such as mismatched impedance, electronic noise, building obstructions,
and reflected signals. In a wireless environment, data transmission
is over the air, and due to the characteristics of this medium,
wireless communication calls for a very different type of technical
knowledge to ensure that your entire wireless network is more
reliable. |
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| Overview |
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| The most widely adopted wireless standards are 802.11a, 802.11b, and 802.11g. 802.11a operates at a frequency of 5 GHz, and supports higher data transfer rates. 802.11b provides a greater coverage area than 802.11a, but at significantly lower data rates. 802.11g, which is the newest of the three standards, combines the best features of 802.11a and 802.11b. 802.11g, and operates at a frequency of 2.4 GHz and supports data rates up to 54 Mbps. |
| Radio
interference normally occurs at specific
frequencies. For example, 802.11g, which
operates at 2.4 GHz, is the most popular
of the main WLAN standards and consequently
it is subject to frequent radio interference. |
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we compare what happens when interference
occurs at the 2.4 GHz frequency when using
the traditional wireless architecture
(single RF) and Moxa's dual-RFenvironment. |
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| Traditional Wireless Architecture |
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| In traditional architectures,
most vendors only provide a single RF
AP and Client, in which the AP connects
one or more Clients to the network. Since
the AP and Client are connected by a single
RF connection at a frequency of 2.4 GHz,
if the interference occurs at 2.4 GHz
then the RF connection will be disconnected,
and the network behind the Client will
be disconnected, too. |
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| Moxa's Dual-RF Wireless Redundancy Typology |
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| Using two
or more frequencies at the same time to
transmit data will allow transmission
to continue even if interference occurs
on one of the frequencies. Moxa's IEEE
802.11 a/b/g-compliant AWK-5222 is equipped
with the newest proprietary wireless redundancy
technology, which has two independent
RF modules, and allows you to set up independent
wireless connections to avoid interruptions
in transmission. Moxa's Dual-RF wireless
redundancy typology provides flexible
frequency configuration and superior reliability.
The two RFs operate at 2.4 GHz; or one
operates at 2.4 GHz and the other at 5
GHz, ensuring double reliability for your
wireless application. |
| For reliability beyond wireless redundancy, Ethernet redundancy is also very important. Moxa's AWK-5222 has two Ethernet ports, and supports RSTP (Rapid Spanning Tree Protocol) and Turbo Ring for the Ethernet side of the connection. |
| As shown in the figure below, Moxa's unique wireless/Ethernet redundancy for rapid failover not only ensures the reliability of the entire wireless network, but also helps you establish the most robust wireless connection for critical industrial wireless applications.
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