Reducing Redundant Alerts

 
 
By Andrew Garcia  |  Posted 2010-04-27
 
 
 

Cisco CleanAir Delivers Networkwide RF Analysis


LAS VEGAS, Nev.-At the Interop IT Expo and Conference, Cisco Systems unveiled new CleanAir Technology comprised of spectrum analysis and diagnosis tools designed to help wireless administrators maintain more stable and consistent wireless LAN performance. Comprised of a new line of Aironet access points with specialized embedded detection hardware and new software revisions for Cisco's data center wireless control elements, CleanAir promises a unique and comprehensive diagnostic solution to the problem of non-WiFi radio interference.

In a recent survey of more than 600 of its customers, Cisco revealed that 78 percent of its customers consider the wireless LAN to be a mission-critical resource-indicating the increasing importance of the WiFi network for those surveyed. Meanwhile, 54 percent of respondents indicated RF interference was causing problems with their WLAN, while an additional 18 percent had no idea if that was the case.    

To address the dichotomy between the importance of the WLAN and the lack of insight into its overall health and performance, Cisco announced its new CleanAir initiative designed to provide its customers with increased visibility into non-WiFi sources of RF energy and interference via spectrum analysis of both of WiFi's unlicensed spectrum bands. Baked into the network infrastructure, CleanAir aims to provide administrators with granular, detailed and accurate RF information to aid troubleshooting and analysis, while also providing the WiFi network the aggregate intelligence to perform automated interference avoidance actions as well.

Spectrum analysis is not a new thing, but the technology has commonly been found in standalone, laptop-based hardware and software setups. With these tools, RF experts needed to walk the halls of the affected site and take readings of the RF environment, a lengthy process that is divorced from remediation actions as the software was not integrated into the network itself.   

Adding spectrum analysis capabilities to access points also isn't a new idea. Aruba Networks recently added the feature to its access points, and Motorola AirDefense products had the capability several years ago. But those companies implemented spectrum analysis in software, using typical WiFi radios to perform the detections.

Cisco's CleanAir differentiates itself by adding specialized spectrum analysis ASICs into their new line of access points, the Aironet 3500 series. By implementing spectrum analysis in hardware, the new APs promise the ability to uniquely identify and track multiple interferers, locate and place them on a map for visualization, and assess each interferer's unique impact on WiFi performance. In this way, administrators can easily gauge an interferers effect on network performance, identify what type of device it is and then accurately pinpoint where it is for quick removal.

Cisco's CleanAir is based upon the technologies purchased as part of Cisco's 2007 acquisition of Cognio. Cisco's Spectrum Expert, which is comprised of PC-based management software and a specialized PC Card for spectrum detection, was licensed for use as part of Fluke Networks' AirMagnet Spectrum Expert. Although AirMagnet continues to sell the Spectrum Expert hardware and software, the company released its new Spectrum XT hardware and software combination earlier this year

With its detections performed with specialized hardware, Cisco CleanAir may be able to more accurately identify the type of device causing the interference than would be possible with a software-only implementation. Cisco representatives claim that software-only implementations may be able to detect RF energy but can't get enough detail about the interference or its source, particularly with multiple interferers present. 

Reducing Redundant Alerts


 

Because the new APs are complemented by the new 7.0 version of Cisco Unified Wireless Network software, CleanAir functionality is integrated into all Wireless LAN Controllers, the Wireless Control System and the 3300 series Mobility Services Engine. With the feature enabled across the network, interference detections can be correlated across multiple access points, potentially reducing redundant alerts from the same source of interference, while at the same time enhancing the accuracy of interferer placement on the heat map. 

Also, Cisco CleanAir allows the network to automatically reconfigure a WiFi cell to avoid interference having too great of an impact on network performance. If the WLC determines air quality is below standard for a particular AP, the cell will automatically transition to a less crowded channel. 

Cisco's Spectrum Expert Connect leverages the Spectrum Expert software component for use with CleanAir. With Spectrum Expert Connect, administrators can send the raw spectrum data from any CleanAir-enabled AP on the network to a laptop running Spectrum Expert. In this manner, RF experts can troubleshoot RF problems remotely, not needing to visit the problematic site. 

With its ties to the MSE and WLC, CleanAir also provides location impact analysis that allows the RF administrator to see on a heat map where an interference source is and what its aggregate impact may be to the network. Administrators can also do historical playback of the interferer, to get a sense of the interferers' effect and placement over time. 

While Cisco recommends the 500 series as the access point of choice for new 802.11n deployments due to CleanAir enhancements, customers that have already deployed 802.11n can utilize a limited number of 3500 series APs (Cisco recommends one 3500 AP for every five APs) as an overlay network. However, customers going this route will not have access to the self-healing capabilities inherent in an end-to-end CleanAir network.

The 3500 series includes three models, with prices ranging from $1,095 to $1,495. At the low end, the 3501i is a single-band (2.4 GHz) access point with internal antenna. The $1,295 3502e offers dual-band 802.11n support and antenna connectors, while the $1,495 3502e supports dual-band 802.11n with external antenna connectors. 

Cisco also announced an addition to the existing Aironet 1200 series of 802.11n access points that does not include CleanAir Technology. The new Aironet 1260 supports dual-band 802.11n with external connectors, and supports 802.3af Power over Ethernet. The 1260 is designed to easily retrofit to fit in the mounting brackets for previously installed Aironet 1130 or 1240 access points.

All new access point models should start shipping in May and include Cisco's new limited lifetime warranty.

 

Rocket Fuel