We have network with ePMP series and somethimes happens that tower loses power and all APs shutdown for a few minutes. We have ACS on and when power comes back, all APs starts to listen and scan freq for the best channel to choose. Since all APs power up at the same time, they also boot up at the same time and they scan the same amount of time and they all select one the same best channel. As you can imagine, this is not the best solution for us. So then we have to run ACS one more time on APs manually and everything is back to normal.
Do you have any suggestion how to improve this situation? (Yes, UPS is already on its way to the tower, I was thinking any other solution)
Hopefully someone will correct me if I am wrong, but I think there is a way to work around this issue.
Under (Tools > Automatic Channel Selection) there are two settings "Minimum Dwell Time" and "Maximum Dwell Time".
I believe you can adjust these values to speed up and slow down how quickly an AP scans for channels so that you could ensure that the APs are finishing at different times and therefore are not choosing the same channel.
Here are a few things to keep in mind.
1) You probably don't want to decrease these values as it may make ACS less reliable (possibly picking channels as if they were clean when they are not).
2) You will probably have to be pretty aggressive with the values. Sector A needs to be transmitting by the time that Sector B gets to that channel to scan.
3) Order your sectors based either on the number of SMs attached or the average distance of the SMs. (If there is only one really clean channel in your area you don't want an AP with only single SM to steal that channel.)
4) This method will be less helpful at the lower end of the band (e.g. 5.1, 5.2) and more helpful at the upper end (e.g. 5.7)
5) Because the APs are coming up at different times you will likely have to lock the SMs to their respective AP to keep them from connecting to the first AP that they see...which may not be the right one.
Again, if this is wrong or there is a better way hopefully someone will jump on and say so.