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HDX Blog Series #4: Optimized Roaming

Editor’s Note: This is the last of a four-part deep dive series into High Density Experience (HDX), Cisco’s latest solution suite designed for high density environments and next-generation wireless technologies. For more on Cisco HDX, visit www.cisco.com/go/80211ac.  Read part 1 here. Read part 2 here. Read part 3 here.

If you’ve been a long time user of Wi-Fi, at some point you have either observed someone encounter (or have personally suffered from) so called “sticky client syndrome”. In this circumstance, a client device tenaciously, doggedly, persistently, and stubbornly stays connected to an AP that it connected to earlier even though the client has physically moved closer to another AP.

Surprisingly, the reason for this is not entirely…errr…ummm…unreasonable. After all, if you are at home, you don’t want to be accidentally connecting to your neighbor’s AP just because the Wi-Fi device you’re using happens to be closer to your neighbor’s AP than to your own.

However, this behavior is completely unacceptable in an enterprise or public Wi-Fi environment where multiple APs are used in support of a wireless LAN and where portability, nomadicity, or mobility is the norm. In this case, the client should typically be regularly attempting to seek the best possible Wi-Fi connection.

Some may argue that regularly scanning for a better Wi-Fi connection unnecessarily consumes battery life for the client device and will interrupt ongoing connectivity. Therefore the “cure is worse than the disease”. But this is true only if the client is very aggressively scanning and actually creates the complete opposite of being “sticky”.

The fundamental issue with “stickiness” is that many client devices simply wait too long to initiate scanning and therefore seeking a better connection. These devices simply insist on maintaining an existing Wi-Fi connection even though that connection may be virtually unusable for anything but the most basic functionality. Read More »

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