Session drops - 20.2.1

hi all,

after upgrading our network to 20.2.1, we are seeing lots of session drops on 450i/450b SMs. all of these SMs are pathed in with accordance to LinkPlanner, but we are seeing unpredictable sessions drops on 20.2.1 . im considering a rollback to 20.2, but havnt done so yet.

are any other network operators seeing this issue too?

We’re seeing the opposite… way less drops with 20.2.1 due to some changes that were made in how IMM works during rapidly fluctuating modulation states.

Is there any more details you can share about these clients that are experiencing issues? What type of AP are they connected to? Do they have strong RSSI, good SnR, and stable high level modulation?

Typically sessions drops are triggered by something… usually you don’t see them in healthy connections.

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I agree with Eric, this doesnt happen with a healthy system.

If it was me I would check all the AP settings and make sure everything is correct and that the timing points are exactly the same across APs and towers that could possibly, even though it would be a remote possibility, hear each other.
If that checks out then a spectrum scan is next to see if someone turned on something that is causing interference. If it is affecting a wide group of SMs across multiple APs then itbis most likely something that the APs are picking up.

Basically instead of using the firmware update as the cause, try isolating the issue to as small of an area as possible and if possible to as few APs as possible. This will usually focus a specific area or tower and will give you a better idea of what is actually happening.

It is possible that there have been some changes in the firmware that has exposed a problem that you were not noticing. But that could also be a good thing, at least now you know about it?

hi all,

all of the SMs that are experiencing session drops have great RSSI and CINR. like, perfect shots. but they modulation will tank and then boom, session dropped. good idea on a competitor turning something up. .

If it’s happening to a lot of clients at the same time, it’s most likely something on the AP side. It could even be self interference if you’re not sync’d properly. If it’s happening to just a few clients at different times, it might be localized interference to those clients. What band are you using?

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