Model Support
Description
Frequency Band Terms
1130, 1240, all 11n indoor
APs, 1522, 1524SB, and
1552 (except -A domain)
Regulations for UNII devices operating in the
5.25- to 5.35-GHz frequency band. DFS and
TPC are mandatory in this band.
UNII-2
1130, 1240, all 11n indoor
APs, 1522, 1524SB, 1552
Regulations for UNII-2 devices operating in
the 5.470 to 5.725 frequency band.
UNII-2 Extended
1130, 1240, all 11n indoor
APs, 1522, 1524
(AP1524PS and
AP1524SB), 1552
Regulations for UNII devices operating in the
5.725 to 5.850 GHz frequency band.
ISM
5
4 UNII refers to the Unlicensed National Information Infrastructure.
5 SM refers to Industrial Science and Mechanical.
The 1552 access points support only the ISM band in the -A domain. The 1552 access points support the
UNII-2 and UNII-2 Extended bands. The DFS algorithms work as expected. The DFS algorithms can be
implemented in the ETSI and other domains, but not in the -A domain. The product certification is pending
the FCC approval and it might take up to 4 months to get the product certified. After the product is certified,
Cisco will provide new software that will allow the UNII-2 and UNII-2 Extended bands to be used for
the 1552 access points in the -A domain.
Note
For regulatory information, see
http://www.cisco.com/en/US/prod/collateral/wireless/ps5679/ps5861/product_
data_sheet0900aecd80537b6a.html
.
Dynamic Frequency Selection
Previously, devices employing radar operated in frequency subbands without other competing services.
However, controlling regulatory bodies are attempting to open and share these bands with new services like
wireless mesh LANs (IEEE 802.11).
To protect existing radar services, the regulatory bodies require that devices wishing to share the newly opened
frequency subband behave in accordance with the Dynamic Frequency Selection (DFS) protocol. DFS dictates
that to be compliant, a radio device must be capable of detecting the presence of radar signals. When a radio
detects a radar signal, it is required to stop transmitting to for at least 30 minutes to protect that service. The
radio then selects a different channel to transmit on but only after monitoring it. If no radar is detected on the
projected channel for at least one minute, then the new radio service device may begin transmissions on that
channel.
The process for a radio to detect and identify a radar signal is a complicated task that sometimes leads to
incorrect detects. Incorrect radar detections can occur due to a large number of factors, including due to
uncertainties of the RF environment and the ability of the access point to reliably detect actual on-channel
radar.
The 802.11h standard addresses DFS and Transmit Power Control (TPC) as it relates to the 5-GHz band. Use
DFS to avoid interference with radar and TPC to avoid interference with satellite feeder links.
Cisco Mesh Access Points, Design and Deployment Guide, Release 7.3
OL-27593-01
25
Mesh Network Components
Cisco Outdoor Mesh Access Points