Question: How to avoid sticky clients using AOS 6.3
Environment: Applies to indoor office space, Warehouse environments with barcode scanners, Dorms with long corridors, Hospital environment with handheld roaming clients.
Clients which tend to connect to a particular AP due to varying factors (High SNR, High Tx power, etc.) and tends to stay associated to the same AP
while the user roams away from the AP and eventually the signal degrades, it termed as a sticky client.
These type of clients tend to hold the association to a far away AP, although a better AP is available to Roam.
How could this be avoided?
Aruba has now come up with the client-match feature starting from ArubaOS 6.3 onwards.
This feature addresses sticky client related issues to a large extent.
How does it work?
Notify all but the candidate AP to restrict association of the client being moved.
Make sure that client is disconnected and then only one AP would be responsive to the client
Each AP monitors SNR for its associated clients
If a client SNR is above a good threshold (25dB SNR), no action is taken.
If the client SNR is below the good threshold, find a “better” AP for the client.
“Better” AP needs to be at least 10 dB stronger than signal of current AP & “Better” AP needs to be have signal of at least -70dBm
If “Better” AP is found, moves the client to it.
AP's would build a beacon report which is shared information and it is based on the probes becing sent from the client to the AP.
Decision to move the client from one AP to the other is taken by using this table as a baseline. The clients are continuously monitored and steered as per matching factors listed above.
How to troubleshoot?
Below are the supportive commands which helps troubleshoot sticky-clients
show ap virtual-beacon-report client-mac <client-mac>
show ap virtual-beacon-report ap-name <ap-name>
show ap arm client-match restriction-table ap-name <ap-name>
show ap arm client-match probe-report ap-name <ap-name> phy-type <80211a/80211g>
show ap arm client-match summary
show ap arm client-match history
show ap arm client-match history client-mac <client-mac>
show ap arm client-match unsupported
show ap arm client-match neighbors ap-name <ap-name>