Cisco Cisco 2000 Series Wireless LAN Controller Guia De Informação
each other. The repeater AP must be within acceptable radio range of the root, or wired, AP.
Q. When do you use an AP as a repeater?
A. You usually use repeater APs in environments where the run of an Ethernet connection is
not practical. Examples include:
not practical. Examples include:
A commercial store with an auto repair shop or garden center in the parking lot,
where the run of Ethernet is not practical.
where the run of Ethernet is not practical.
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Historic sites and other buildings in which cabling is not permissible.
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Large open areas where cabling is not desirable.
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Use repeaters to serve client devices that do not require high throughput. Repeaters
extend the coverage area of your wireless LAN (WLAN), but they drastically reduce
throughput.
extend the coverage area of your wireless LAN (WLAN), but they drastically reduce
throughput.
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Use repeaters when most, if not all, client devices that associate with the repeaters are
Cisco Aironet clients. Non−Cisco client devices sometimes have difficulty
communicating with repeater APs.
Cisco Aironet clients. Non−Cisco client devices sometimes have difficulty
communicating with repeater APs.
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Q. Does the AP only scan frequencies when you switch on the AP for the
first time?
first time?
A. Yes, AP samples all frequencies when you first switch on AP. AP settles on the frequency
with the least activity after power−on self test (POST) or restart. Frequency agility does not
relieve you of the responsibility of channel coordination. Frequency agility is simply a feature
that makes implementation with minimum interference easier for users who are new to
wireless LANs (WLANs).
with the least activity after power−on self test (POST) or restart. Frequency agility does not
relieve you of the responsibility of channel coordination. Frequency agility is simply a feature
that makes implementation with minimum interference easier for users who are new to
wireless LANs (WLANs).
Note: In installations with more than one AP, do not allow each device to search separately
for least congested frequencies. The RF environment needs management in accordance with
the report from a qualified site surveyor.
for least congested frequencies. The RF environment needs management in accordance with
the report from a qualified site surveyor.
Q. Why is there not much information on the Cisco Aironet AP 4800,
model number AP4822B? Has there been a discontinuation of the
model? Is this unit a pre−Cisco brand?
model number AP4822B? Has there been a discontinuation of the
model? Is this unit a pre−Cisco brand?
A. The AP4800B is the same hardware as the AP340. You can download the latest 340 code
on the model and operation is normal. There are later 4800 units with no B in the model
number. You cannot use the 340 software on these units, although these later units still
interoperate. Refer to End−of−Sale and End−of−Life Product for details on end−of−sale and
end−of−life products.
on the model and operation is normal. There are later 4800 units with no B in the model
number. You cannot use the 340 software on these units, although these later units still
interoperate. Refer to End−of−Sale and End−of−Life Product for details on end−of−sale and
end−of−life products.
Antennas
Q. What is the role of an antenna in a wireless LAN (WLAN)?
A. An antenna is a device used to transmitt or receive signals. Antennas convert electrical
energy into radio frequency (RF) waves when it transmits, or RF waves into electrical energy
when it receives. The size and shape of antennas are determined primarily by the frequency of
the signal they are designed to receive. A high gain antenna is highly focused, whereas a low
gain antenna receives or transmits over a wide angle. An antenna provides the wireless
system with three fundamental properties: gain, direction, and polarization.
energy into radio frequency (RF) waves when it transmits, or RF waves into electrical energy
when it receives. The size and shape of antennas are determined primarily by the frequency of
the signal they are designed to receive. A high gain antenna is highly focused, whereas a low
gain antenna receives or transmits over a wide angle. An antenna provides the wireless
system with three fundamental properties: gain, direction, and polarization.