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Force Flow
Asked: 2012-09-25 13:16:55 +0800 CST

Wireless connection silently dies randomly

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I have two WAP4410N wireless access points powered using Power-Over-Ethernet.

They are both connected to the same LAN and broadcasting the same SSID with a WPA2 password.

One is using channel 1, while the other is using channel 11.

There is coverage overlap where the signal from both access points hover around -75db to -85db while standing in the same physical location.

DHCP is disabled, and is being provided by another network device.

Every day or so, devices can connect and authenticate to the access points, but are not granted an IP address (and subsequently are unable access to the LAN or Internet). For devices that had already retrieved an IP address prior to the issue exhibiting itself, the devices simply stop communicating with LAN and Internet.

However, I can still access each access point's web admin interface from the LAN.

If I reboot both devices, the problem vanishes and devices are once again able to get an IP address and connect to the LAN and Internet.

Are these symptoms of signal interference between the two WAPs or is this a completely different issue?

networking

2 Answers

  1. Are these symptoms of signal interference between the two WAPs or is this a completely different issue?

    Unlikely but a spectrum analyzer could tell your for sure. There may be other devices in the 2.4GHz band that are effecting your clients.

    Every day or so, devices can connect and authenticate to the access points, but are not granted an IP address (and subsequently are unable access to the LAN or Internet). For devices that had already retrieved an IP address prior to the issue exhibiting itself, the devices simply stop communicating with LAN and Internet.

    Can you confirm this via some sort of logging capability on the access point themselves? There's a huge spectrum of wireless hardware and not all it plays nice together or is well built. I have seen a few instances of clients reporting the they are associated but the access point does not record their associations. Changing the wireless card on the client resolved the issue.

    If I reboot both devices, the problem vanishes and devices are once again able to get an IP address and connect to the LAN and Internet.

    This is the crux of it. The fact that you can temporarily "resolve" this by rebooting the access point without making any changes elsewhere inclines me to believe the issue is with the access point itself. You should verify that rebooting the access point does "resolve" this issue by waiting until a client reports the problem, verifying that the problem exists and then reboot the access point to see if it resolves. Do not physically move the client once it generates this issue, as it might simply be that users report the issue, move somewhere else and the issue isn't present any more due to better signal strength instead something related to access point.

    If you are not using Enterprise or Business grade access points your problem is likely best solved by replacing them with appropriate devices. The economics of commodity grade 802.11 equipment does not encourage the production of resilient devices.

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  2. Best Answer

    I got ahold of a cisco support engineer about the issue, and as it turns out, this is a known issue with this particular model. The issue was supposedly addressed in firmware 2.0.6.1, but it is still occurring for my WAPs.

    Since the model is approaching EOL, the cisco engineer said there would be no further firmware updates for the issue.

    As a result, I plan on replacing all the WAP4410N with a different brand and model.

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