topic Re: Flgged high Lantency reading in SmartZone and Virtual SmartZone

Flgged high Lantency reading

rodger_ng_4a708 — Tue, 02 Feb 2021 04:46:43 GMT

I been monitor the a few newly deploy Access point where VSZ-E is showing high latency on 2.4Ghz and 5 Ghz, where number of user are only 5 or less. It been flagged and Latency have not recover since deployment

Do anyone have this issue?

Any idea is this a bug or what is the possible cause of the latency.

Thanks for Answering in advance.

Re: Flgged high Lantency reading

toomas_kadarpik — Tue, 02 Feb 2021 05:18:30 GMT

As far as I remember, latency is montoring Wi-Fi protocol ACK packets and mostly it referres to CA network occupancy, i.e network is busy or packets have disappeared due to radio propagation and retransmitted.

Re: Flgged high Lantency reading

eizens_putnins — Tue, 02 Feb 2021 08:07:36 GMT

It usually means that some neighbor network uses same channels. Take a look on channels used around and change AP channel settings accordingly.

Hope it helps

Re: Flgged high Lantency reading

syamantakomer — Tue, 02 Feb 2021 17:43:25 GMT

Hi Rodger,

I will always start with controller model, firmware version, number of APs connected to it and how close APs are installed.

Another major point is, AP stats flagging is set to default, so default settings may not be ideal for all type of installations, for example dense environments.

Change the flag sensitivity (set to low) and threshold (to high) depending upon how close APs are installed and how fair this environment is.

For more about the feature, refer below article which will give you some additional information.

https://support.ruckuswireless.com/articles/000006278

Re: Flgged high Lantency reading

rodger_ng_4a708 — Mon, 08 Feb 2021 06:40:45 GMT

Controller VSZ-E

Cotroller Version 5.2.1.0.515

Total 22 AP spread into 4 floor

Each AP is nearest about 15 meter apart with wall and partition in between.

AP model Ruckus AP650

Re: Flgged high Lantency reading

rodger_ng_4a708 — Mon, 08 Feb 2021 07:02:24 GMT

Also received Drop call from Microsoft Team using Ruckus wifi.,LAN got no issue not sure is the latency causing it?

Re: Flgged high Lantency reading

toomas_kadarpik — Mon, 08 Feb 2021 07:18:05 GMT

Dos anyone know how the KPI-s are calculated in Zone-Access Points view ? If I see 5 GHz latency 120 ms , is it maximum, is it 5 min maximum or is it average ?

Re: Flgged high Lantency reading

eizens_putnins — Mon, 08 Feb 2021 07:53:45 GMT

I don't now how it is calculated, but anyway 120 ms is gross and means you have real problem. 10-20 ms is acceptable, but not over 100ms. Look on spectrum analyzer data and try to change channels to less crowded. It definitely is interference of some kind. With latency 120 ms you most probably have also a lot of dropped packets and retransmissions, which is very bad for video calls.

Check that your APs are on different channels (sometimes vSZ doesn't set channels reasonably) - there must be no same channels set on neighbor APs.

I also usually recommend to set on each SSID OFDM-only mode with min-rate 12mb/s in most cases (in your case you can use even 24mb/s, as distance from clients to AP is small). This ensures that client connection is to nearest AP and is fast enough, so interference becomes less important (except if it is very strong).

Anyway usually changing channel fixes that. Of cause, if problem reason is the neighbor AP, it can change it channel too and make problems again. It's a real life!

Re: Flgged high Lantency reading

eizens_putnins — Mon, 08 Feb 2021 08:05:24 GMT

So start from looking on channels for flagged APs and they nearest neighbors. If they are different, than check spectrum analyses data, to see which channels are better. Check on-site, if you have neighbor network making interference for you -- it will be clearly visible with any analyzer on phone -- look for other APs with same or near channel and signal strength over -75-80 db. Usually you can make a good guess about source of interference by name of SSID and even find location of that AP more or less.

I have seen in some cases interference created by cheap wireless video surveillance cameras (which use analog video transmission, and it blocks actually all 2.4GHz band), but you have both bands affected, so it is most probably WiFi interference.