Руководство По Проектированию для Cisco Cisco Aironet 1522 Lightweight Outdoor Mesh Access Point
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Cisco Mesh Access Points, Design and Deployment Guide, 7.2
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Design Considerations
There is no current software limitation on how many MAPs per RAP you can configure. However,
it is suggested that you limit the number to 20 MAPs per RAP.
it is suggested that you limit the number to 20 MAPs per RAP.
•
Number of controllers
–
The number of controllers per mobility group is limited to 72.
•
Number of mesh access points supported per controller. For more information, see the
section.
ClientLink Technology
Many networks still support a mix of 802.11a/g and 802.11n clients. Because 802.11a/g clients (legacy
clients) operate at lower data rates, the older clients can reduce the capacity of the entire network.
Cisco’s ClientLink technology can help solve problems related to adoption of 802.11n in mixed-client
networks by ensuring that 802.11a/g clients operate at the best possible rates, especially when they are
near cell boundaries.
clients) operate at lower data rates, the older clients can reduce the capacity of the entire network.
Cisco’s ClientLink technology can help solve problems related to adoption of 802.11n in mixed-client
networks by ensuring that 802.11a/g clients operate at the best possible rates, especially when they are
near cell boundaries.
Advanced signal processing has been added to the Wi-Fi chipset. Multiple transmit antennas are used to
focus transmissions in the direction of the 802.11a/g client, increasing the downlink signal-to-noise ratio
and the data rate over range, thereby reducing coverage holes and enhancing the overall system
performance. This technology learns the optimum way to combine the signal received from a client and
then uses this information to send packets in an optimum way back to the client. This technique is also
referred to as MIMO (multiple-input multiple-output) beamforming, transmit beamforming, or
cophasing, and it is the only enterprise-class and service provider-class solution in the market that does
not require expensive antenna arrays.
focus transmissions in the direction of the 802.11a/g client, increasing the downlink signal-to-noise ratio
and the data rate over range, thereby reducing coverage holes and enhancing the overall system
performance. This technology learns the optimum way to combine the signal received from a client and
then uses this information to send packets in an optimum way back to the client. This technique is also
referred to as MIMO (multiple-input multiple-output) beamforming, transmit beamforming, or
cophasing, and it is the only enterprise-class and service provider-class solution in the market that does
not require expensive antenna arrays.
The 802.11n systems take advantage of multipath by sending multiple radio signals simultaneously.
Each of these signals, called a spatial stream, is sent from its own antenna using its own transmitter.
Because there is some space between these antennas, each signal follows a slightly different path to the
receiver, a situation called spatial diversity. The receiver has multiple antennas as well, each with its own
radio that independently decodes the arriving signals, and each signal is combined with signals from the
other receiver radios. This results in multiple data streams receiving at the same time. This enables a
higher throughput than previous 802.11a/g systems, but requires an 802.11n capable client to decipher
the signal. Therefore, both AP and client need to support this capability. Due to the complexity of issues,
in the first generation of mainstream 802.11n chipsets, neither the AP nor client chipsets implemented
802.11n transmit beamforming. Therefore, the 802.11n standard transmit beamforming will be available
eventually, but not until the next generation of chipsets take hold in the market. We intend to lead in this
area going forward.
Each of these signals, called a spatial stream, is sent from its own antenna using its own transmitter.
Because there is some space between these antennas, each signal follows a slightly different path to the
receiver, a situation called spatial diversity. The receiver has multiple antennas as well, each with its own
radio that independently decodes the arriving signals, and each signal is combined with signals from the
other receiver radios. This results in multiple data streams receiving at the same time. This enables a
higher throughput than previous 802.11a/g systems, but requires an 802.11n capable client to decipher
the signal. Therefore, both AP and client need to support this capability. Due to the complexity of issues,
in the first generation of mainstream 802.11n chipsets, neither the AP nor client chipsets implemented
802.11n transmit beamforming. Therefore, the 802.11n standard transmit beamforming will be available
eventually, but not until the next generation of chipsets take hold in the market. We intend to lead in this
area going forward.
We realized that for the current generation of 802.11n APs, while the second transmit path was being
well utilized for 802.11n clients (to implement spatial diversity), it was not being fully used for
802.11a/g clients. In other words, for 802.11 a/g clients, some of the capabilities of the extra transmit
path was lying idle. In addition, we realized that for many networks, the performance of the installed
802.11 a/g client base would be a limiting factor on the network.
well utilized for 802.11n clients (to implement spatial diversity), it was not being fully used for
802.11a/g clients. In other words, for 802.11 a/g clients, some of the capabilities of the extra transmit
path was lying idle. In addition, we realized that for many networks, the performance of the installed
802.11 a/g client base would be a limiting factor on the network.
To take advantage of this fallow capacity and greatly enhance overall network capacity by bringing
802.11 a/g clients up to a higher performance level, we created an innovation in transmit beamforming
technology, called ClientLink.
802.11 a/g clients up to a higher performance level, we created an innovation in transmit beamforming
technology, called ClientLink.
ClientLink uses advanced signal processing techniques and multiple transmit paths to optimize the
signal received by 802.11a/g clients in the downlink direction without requiring feedback. Because no
special feedback is required, Cisco ClientLink works with all existing 802.11a/g clients.
signal received by 802.11a/g clients in the downlink direction without requiring feedback. Because no
special feedback is required, Cisco ClientLink works with all existing 802.11a/g clients.
Cisco ClientLink technology effectively enables the access point to optimize the SNR exactly at the
position where the client is placed. ClientLink provides a gain of almost 4 dB in the downlink direction.
Improved SNR yields many benefits, such as a reduced number of retries and higher data rates. For
position where the client is placed. ClientLink provides a gain of almost 4 dB in the downlink direction.
Improved SNR yields many benefits, such as a reduced number of retries and higher data rates. For