Overview of WLAN fault repair in Wireless LAN

Wireless local Area network (small) in the past, is used to send and receive e-mail and browsing the web, the wireless LAN is usually used by radio frequency experts manual tools to troubleshoot network failures. However, as the data flow size and diversity become more and more significant, coupled with wireless LAN has become one of the main means of network access, wireless LAN fault repair methods have been rapid growth.

How WLAN management tools improve the ability of WLAN troubleshooting

As 802.11 is increasingly being used in a variety of consumer electronics, such as laptops, small netbooks, smartphones, printers, cameras, and so on, the user's ability to connect to the network in different places varies depending on the device. For best results, the Advisory desk must have a high degree of insight into both historical and real-time data.

This is one of the main reasons why WLAN management tools are now in the mainstream. For example, the Meraki ' s cloud controller can display near-real-time state data for each connected client. In addition, it can provide some basic functions (such as the identification of connected AP, ping the client on the AP, and monitor input or output counters, etc.). The use of this controller is quite simple for the consulting desk, and it is convenient for them to view the content only on the web.

However, as the complexity of the network becomes more and more obvious, the difficulty of the corresponding troubleshooting is increasing. At present, the client is free and fast to roam between several APS; some offices are likely to be connected by different types of AP from different brands, and good third-party WLAN management is usually more secure. For example, Aruba's Airwave Management platform can display the AP of multiple suppliers, and adjust according to the client's position characteristics, such as consulting desk, network Operation Center, or engineers. There will be real-time monitoring and mapping for each connection and will be recorded for trend analysis. The goal is to quickly identify the source of the fault, is the user error, client configuration, network interruption, weak signal, or signal blocking problems. Similar to the Aruba Airwave monitoring tool, which solves most of the first-tier network problems, requires reporting to a higher level of engineer (second or third tier) if other problems arise.

Dynamic WLAN testing using a distributed sensing platform

Of course, the most important thing is to identify, detect, and then eliminate the failure before it affects the user experience. It is for this reason that businesses typically run automated Network Diagnostics tests-regularly connecting to critical servers and applications to quickly identify NOC failures.

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However, it is difficult to make network guarantees in WLANs, because users in the WLAN are moving more frequently. To know that the AP is not the same as verifying this from a different location, a wireless client using a different SSID or band can connect to the AP. For the latter, you can consider tools similar to the Motorola Airdefense Network assurance Suite or 7signal Sapphire.

These tools all use a long-distance configuration Wi-Fi sensor to create a distributed test platform. For example, the Airdefense Suite is an extension of the Wireless Intrusion Prevention System (WIPS), which can be connected to the nearby AP on a regular basis, just like a "real" client. Once connected, the client of these sensors can run a network guarantee test, alert the NOC in advance, and provide diagnostic data (for example, remote packet capture, or other key metrics).

Signal quality monitoring using an AP Based Spectrum analyzer

In a WLAN, a failure caused by a user error, client configuration, or an uplink network/application crash is not "automatically recovered." However, sometimes the signal coverage is weak, or the RF interference caused by the failure, but can be achieved through the AP and the controller to restore self-healing.

Almost all AP have the characteristic of matching the best channel. For some controllers, the administrator can immediately release some channels, or set how long to detect again. The algorithms for wireless resource management vary, but it is often the AP and their signal strength on each channel that needs to be considered. C in the 5GHz DFS channel, other signal transmitter (such as radar system) also need to take into account.

However, the problems caused by non-802.11 disturbances are more difficult to diagnose or avoid. When encountering such faults, the traditional approach is to use hand-held signal analyzer for sampling, this method has certain limitations. Scattered disturbances may not be transmitted at the time of sampling. In noisy high density places, the spectral map is difficult to describe the specific situation vividly. When the sample value is clear, the solution can be changed again.

To overcome these limitations, several vendors, including Aruba, Cisco, Meraki and Motorola, are now providing an AP-based Spectrum analyzer. Although the performance of these analyzers varies, this type of tool uses the AP to monitor non 802.11 interference. There are even several products that use digital signatures to identify disturbances (such as cameras, telephones, etc.). For example, Cisco's clean Air can periodically set Aironet 3500 AP to monitoring mode to analyze 2.4 and 5GHz disturbances, and can redistribute channels to avoid 802.11 and 802.11 interference.

When the wireless LAN is again the Enterprise component type, often encounter some network failures, such as the wireless signal instability, can search for the signal could not dynamically obtain IP address, often appear instantaneous disconnect and even the first-class phenomenon is often happening, then, the above wireless LAN fault Repair measures is a good way to rescue.