Sniff Wi-Fi

Auto-channel selection protocols have been an increasingly common source of controversy for enterprise Wi-Fi administrators.  Aruba's ARM, Cisco's RRM, Ruckus's ChannelFly and Aerohive's ACSP all allow a centralize management entity -- either controller or software -- to automatically set the channels of access points (APs).  These protocols can be big time savers during the surveying and implementation stages, but also can cause big headaches once the Wi-Fi is up and running.   The argument over whether to use auto-channel selection protocols may be coming to an end, however.  802.11k is becoming more widely supported in Wi-Fi devices, and when smartphones, tablets and other devices support 802.11k, the decision is a no-brainer: auto-channel should be avoided because it makes roaming worse. To understand the impact that 802.11k (radio resource measurement) has on Wi-Fi devices, one first must understand a fundamental fact about Wi-Fi: devices control connections.

There is a dirty little secret in the world of enterprise Wi-Fi: auto-channel selection doesn't work very well.  Every wireless LAN vendor has it.  Every wireless LAN vendor promotes it.  But when the Wi-Fi gets busy or crowded of full of mobile devices, auto channels will leave users frustrated and admins confused.   What to do about enterprise auto-channel?  Why, fix it, of course.  Here are some tips for getting it fixed the right way. First, the positive side of auto-channel: it saves you time.  Auto-channel selection is one of the two primary parts of auto-RF protocols that are supported by enterprise controllers, APs and management systems.  (The other part is auto-transmit power.)  Auto-RF protocols automatically adjust channel numbers and transmit power levels on APs.  Auto-RF protocols use information received by a large number of APs to decide when to adjust.  What that means is that if an AP senses a microwave oven baking channel 11 every time Jessica re-heats her h