Problems with old WLAN Clients after changing the WLAN infrastructure

[Anonymous]

Hello,

we switched our wlan infrastructure at one of our warehouses from old Motorola Symbol Aps using a WEP SSID to our new wlan infrastructure using the XIQ Cloud, with primarily AP410 and a PPSK SSID, using one PPSK for every forklift in the warehouse. (They use an old Win7 embedded OS).

After the switch we noticed several disconnects within the Logistics Software we are using on the terminals to manage the warehouse. We Software keeps losing the connection to the server for a few seconds (from 2-3 seconds to 15-20) and then reconnects. It seems like it’s happening all over the warehouse, even at locations where i can see with our other devices that the wlan connections seems good and stable. What i’ve noticed is that it looks like some sort of roaming problem to me. It seems to me like it is some sort of roaming problem. Maybe the terminals take too long to roam between the aps or having problems with PPSK authentication?

I checked the client monitor to check the clients and noticed a poor client health. Seeing many issues displayed as “The client is configured with an incorrect static IP address or gateway.” Which in fact, seems not to be correct. The forklifts are configured with a static ip, dns and gateway (we dont use DHCP in this VLAN). So what is the cause of this error? Could the be also a hint to our main wlan problem? 

If you need any more information, dont hesitate to ask. I appreciate every help. 🙂

[Ovais_Qayyum]

Hi Florian,

You can upload the capture files to OneDrive/SharePoint or any other file-sharing service and share the link here. We have some obvious variables, 67 Vs 50 APs, Internal Vs external antennas which will change the coverage in your environment 100%. As for your question on “shouldn’t the newer and more “intelligent” aps able to cover the area as good as the old ones or at least more optimized?”   

YES, provided we stick by the fundamentals of RF design, just can't beat the physics. And, let's also consider the fact that you are still using the new APs with the same old clients, which will make your APs work in backward compatibility mode. Hence, performance will be limited to the capability of clients, you won’t be able to take full advantage of the advanced RF features that the new AP has to offer.   

Do you remember which external antennas on the AP5131 did you use? model no. will help. I can then compare the coverage pattern on AP5131 external with external and the AP410C.

Regards,

Ovais

[Anonymous]

Hello Orvais,

I just checked the CRC Rates on two of the Aps which had a high rate on Friday again and know it’s pretty low. One ist at 9%, the other at 13%. The rretry rate is at 4% and 5%.
 

I’ve got two packet captures (one from friday and one from today). How i should i post them here? Guess with the character limit of 3000 i cant post really much. 

What I’ve noticed so far is a decent amount of blocked requests by the ap because of too low bitrates (basic is 11mbit most of them are either 1mbit or 9).

But shouldn’t the newer and more “intelligent” aps able to cover the area as good as the old ones or atleast more optimized? We did place them like the wlan coverage by our partner reccomended them. I would guess that the motorola aps had way more overlapping cells than the current one causing more interferences. But that is only guess. I never heard of any intense problems with the old wlan for as long as i am working in the company.

We were not told about any disadvantages of using the 410cs for our infrasctructure.

[Ovais_Qayyum]

I would wait for packet capture (you can take it remotely from any AP by following the screenshot in my previous response) to see if my suspicion about retransmissions is correct, which in fact will cause the application to terminate the session. If we see retransmission of packets then it would solely be an RF design problem, Tx power wouldn’t play much of a role in there.

Looking at the CRC error rate alone i.e. 46%, not many latency-sensitive applications will survive that.

Some other clues from our discussion so far:

1- 67 APs were replaced with 50 APs.

2- External antenna Vs. integrated antennas (this one alone can be causing this entire issue).

3- External antennas may have had different gain and radiation patterns for sure, which doesn’t match your current integrated antenna APs.

4- If the APs are deployed at a height of 30-36 feet (normal for warehouses) then integrated antennas are not a good choice due to the dipole type side-side Omni radiation pattern, which won't focus most of the signal on the ground.   

Regards,

Ovais 

[Anonymous]

Yes. They are already configured like your screenshot. 

[dpanev]

13-15 is what extreme says in their workshops.

Did you check your Rate Settings?: