Cisco aironet 1522 Design And Deployment Manual page 49

Collocating AP1520s on Adjacent Channels
If two collocated AP1520s are operating on adjacent channels such as channel 149 (5745 MHz) and
channel 152 (5765 MHz), the minimum vertical separation between the two AP1520s is 40 feet. (This is
true for mesh access points equipped with either 8 dBi omni-directional or 17 dBi high-gain directional
patch antennas).
If two collocated AP1520s are operating on channels 1, 6 or 11 (2412 to 2437 MHz) with a 5.5 dBi
omni-directional antenna, then the minimum vertical separation is 8 feet.
Collocating AP1520s on Alternate Adjacent Channels
If two collocated AP1520s are operating on alternate adjacent channels such as channel 149 (5745 MHz)
and channel 157 (5785 MHz), the minimum vertical separation between the two AP1520s is 10 feet.
(This is true for mesh access points equipped with either 8 dBi omni-directional or 17 dBi high-gain
directional patch antennas).
If two collocated AP1520s are operating on alternate adjacent channels 1 and 11 (2412 and 2462 MHz)
with a 5.5 dBi omni-directional antenna, then the minimum vertical separation is 2 feet.
In summary, 5-GHz antenna isolation determines mesh access point spacing requirements and antenna
proximity must be obeyed, and is dependent upon adjacent and alternate adjacent channel usage.
Special Considerations for Indoor Mesh Networks
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Cisco Aironet 1520, 1130, 1240 Series Wireless Mesh Access Points, Design and Deployment Guide, Release 6.0
OL-20213-01
Voice is only supported on indoor mesh networks in release 5.2 and
Quality of Service (QoS) is supported on the local 2.4 GHz client access radio and on the 5-GHz
and 4.9-GHz backhauls.
Cisco also supports static Call Admission Control (CAC) in CCXv4 clients which provides CAC
between the access point and the client.
RAP-to-MAP ratio–Recommended ratio is 3 to 4 MAPs per RAP.
AP-to-AP distance–A spacing of no more than of 200 ft between each mesh access point is
recommend with a cell radius of 100 ft.
Hop count–No more than 2 hops
RF considerations for client access on voice networks:
Coverage hole of 2 to 10 percent
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Cell coverage overlap of 15 to 20 percent
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RSSI and SNR values that are at least 15 dB higher than data requirements. For example, an
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RSSI of -67dBm is recommended on an 11 or 12 Mb/s link with an SNR of no more than 25 dB.
Likewise, an RSSI of -56 dBm is recommended on a 56 Mb/s link with an SNR of no more than
40 dB.
An RSSI of -62 dBm is recommended on a 24 Mb/s 802.11a backhaul when universal access is
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configured and client traffic is present.
Packet error rate (PER) must be configured for a value of one percent or less.
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Channel with the lowest utilization (CU) must be used. Check the CU when no traffic is running.
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Radio resource manager (RRM) can be used to implement the recommended RSSI, PER, CU,
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cell coverage and coverage hole settings on the 802.11b/g radio. (RRM is not yet enabled on the
802.11a radio).
Site Preparation and Planning
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