In my experience, barcode scanners run Telnet based applications that are very
sensitive to time delays and dropped packets. Using only standalone APs means
the scanners will have to re-authenticate with every roam. Having a ZoneDirector
allows for the cached client session credentials to be shared between APs and
allows for more seamless roaming, especially for VoIP and Scanner usage.
Hi Marco, The 802.11 standard explicitly places control of wireless connection establishment in the hands of clients by defining various logical services and breaking implementation out between clients and access points."
Even if controller is there you shall keep in mind that roaming will NOT always be smooth due due to the fact that decision and how fast to roam is taken care by STA or client.
The fastest client re-association is facilitated by ZoneDirector managing client
sessions between Access Points under its control. Without a ZoneDirector, the
scanner is dropping from one AP, and performing an entire new connection to the
next AP, including another DHCP request, and will result in a few lost packets by
the scanner telnet application. If these dropped packets are enough to freeze the
application or cause it to lose session with the server will have to be evaluated,
but for best results, the ZD is a valuable piece of the solution.