Wireless Troubleshooting Facts

Wireless Troubleshooting Facts

If you are having trouble establishing or keeping a wireless connection, consider the following:

Consideration	Description
Incorrect configuration	Probably the most common source of problems with wireless networking is incorrect configuration. Before considering other problems, verify that the correct SSID and WEP/WPA keys have been configured. Remember that WEP/WPA keys are not case-sensitive, but passphrases are case-sensitive.
Range and obstructions	Wireless standards have a limited range. Moving a client outside of the effective range will weaken the signal and likely cause intermittent reception while moving outside of the stated range can cause it to be completely dropped. In addition, many wireless devices have trouble transmitting through obstructions in the path. Infrared requires a line-of-sight path, while radio frequency wireless has trouble transmitting through certain materials such as concrete.
Channel interference	The 2.4 GHz frequency range is divided into 11 channels, with each channel having some overlap with the channels next to it. You might experience problems with your wireless network when other devices are trying to use the same or adjacent channels. Devices that use radio frequency wireless include: Cordless telephones Other access points in the area (for example, each of your neighbors might have a wireless network, with each configured to use a similar channel) To avoid interference, try changing the channel used on the access point. If the area has different wireless networks, configure each with a different channel with at least two channels separating the channels in use (for example you can use channels 1, 4, 8, and 11).
Atmospheric and EMI conditions	Interference from atmospheric conditions such as weather or other sources of stray radio waves (electro-magnetic interference) can degrade the signal and cause service interruptions.
Antennae orientation	For some 802.11 devices, the antenna orientation might have a small effect on signal strength. There are two types of antennas you should be aware of: Directional antenna: Creates a narrow, focused signal in a particular direction. Focused signal provides greater signal strength increasing the transmission distance. Provide a stronger point-to-point connection, better equipping them to handle obstacles. Omni-directional antenna: Disperses the RF wave in an equal 360-degree pattern. Used to provide access to many clients in a radius. For other devices such as infrared or satellite, the orientation of the receiving device is critical. For these types of devices, make sure the receivers have a line-of-sight path to communicate.
Client and access point incompatibility	In some cases, especially when using 802.11n, the wireless client might not be compatible with the wireless access point. Try updating the software that came with the wireless client, update the firmware on the access point, and research the manufacturer's Web site for additional information. Because of the large number of vendors of wireless devices for clients, Cisco wants to ensure that the vendors' devices will work with Cisco access points. The Cisco Compatible Extensions (CCX) program allows manufactures of wireless network devices to send their products to a third-party testing lab to ensure that they will work with Cisco access points.

 

 

Credit: Testout 640-802 CCNA Notes