Performance Alarms

Performance Alarms alert you to events that provide critical information about the service levels of the wireless network. In a wireless environment, Performance events can be an indication of problems related to configuration, compatibility, congestion, coverage, potential interference sources, and utilization levels. Because 802.11 operates in a shared and unlicensed frequency spectrum, it is possible that performance issues may be the result of non 802.11 devices such as microwaves and cordless phones, or could be a result of a conflict with other 802.11 devices, including both valid devices as well as neighboring devices transmitting into the monitored airspace.

Performance Alarms are broken down into the following eight sub-types:

• AP Testing - AP Testing Events track network failures and provide proactive notification that the network resources may be unavailable. The alarms in this category indicate a failure of one of the test conditions. Any alarm should be considered a high priority event as it may be preventing the wireless applications from operating properly.

  These connectivity tests can be run automatically or manually. The AP test uses the deployed sensors as a wireless station to connect to an AP and validate the available resources. The test validates wireless authentication, encryption, DHCP, ACL, firewall testing, general network connectivity and application availability testing.

• Configuration/Compatibility - 802.11 Wireless networks operate in unlicensed frequency ranges capable of operating in numerous different configurations. Monitoring the wireless devices operating configuration will ensure maximum compatibility and network performance.
• Congestion - 802.11 Wireless network operate in a shared and uncontrolled medium; congestion is inevitable as the number of wireless devices and bandwidth demands increase. AirDefense Enterprise proactively monitors for congestion problems to ensure maximum performance on the wireless network.
• Coverage - 802.11 Wireless networks operate in unlicensed frequencies; however the allowable power output by any single device has been regulated. This limits range and coverage capable by any single 802.11 capable wireless device. The main causes of coverage problems are related to deployments. AirDefense Enterprise provides detections of coverage problems to assist in troubleshooting specific areas of the wireless networks.
• LiveRF - LiveRF is a tool to that uses live data from sensors and WLAN infrastructure to provide real-time visualizations of the environment. The use of live data feeds ensures the visualizations accurately represent environmental changes and transient issues which may not have been captured in the plan or site survey. Visualizations provided allow administrators to troubleshoot wireless connectivity, throughput issues, capacity problems and identify RF interference sources for a floor or entire building. All of this is performed from a central console, so troubleshooting can be performed without having to send administrators out to remote locations. LiveRF also allows runs in the background to automatically detect network problems based on thresholds defined by the administrator. The alarms in this category are a result of these proactive network problem detection capabilities.
• Potential Interference Sources - 802.11 devices operate in unlicensed frequency ranges, 2.4GHz for b/g and 5GHz for a-channels and are subject to interference from other devices utilizing the same frequency. Common examples of these devices are: microwave ovens, Bluetooth devices, baby monitors, cordless telephones, Zigbee devices, non 802.11 wireless security cameras and wireless USB devices (wireless keyboard and mouse).
• RF Spectrum Analysis - 802.11 Wireless networks operate in unlicensed frequencies. This includes any non 892.11 transmitters such as cordless phones, and Bluetooth share frequency spectrum with 802.11 wireless networks. A non 802.11 transmitter can impact the network by causing interference. Identifying the source is difficult with standard 802.11 hardware as these simply appear as noise. Spectrum Analysis can be used to identify the source of the interference and judge the impact the interferer will have on the wireless network.
• Utilization - 802.11 Wireless networks operate in a medium where all devices share the available bandwidth. Any single device is capable of impacting performance by using all available wireless resources. AirDefense Enterprise monitors over 50 performance related utilization statistics for the authorized wireless devices, to ensure that utilization related performance problems are discovered before causing significant wireless network performance degradation.