Iphone Lost ICMP Packets Cisco WLC 3504

[patrickebert]

Hello, everyone,

I have a problem with iPhone phones and Cisco WLC 3504 with 66xAP1852.

Unfortunately it is not possible to make phone calls via VOIP without problems.

But this is not Jabber.

I use 802.1x with user authentication.

Firmware: 8.5.140

Here's the thing:

The iPhone breaks off during the phone call, because every now and then the iPhone switches to mobile radio.

Bandwidth is 140mbit/s everywhere.

Illumination was measured with 58dbm.

In order to find out the cause of the error, I downloaded the App inetTools and noticed that every now and then an ICMP package gets lost.

Mostly when the AP change takes place.

Samsung A8, as well as Samsung A5 devices do not have these problems.

Can anyone help me here?

I added the sh run-config directly and the output from "debug client <Mac-addr>"

Best Regards from Germany 

Patrick Ebert

[patoberli]

Hallo Patrick

Before I have a long look at your configuration file, which SSID are we talking about?

Gruss
Patrick

[patrickebert]

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@patoberli wrote:
Hallo Patrick

Before I have a long look at your configuration file, which SSID are we talking about?

Gruss
Patrick

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Hello, we are talking about the SSID "VOMOB"(802.1x) and for test purposes SSID "iphone" via psk.
but I have the same problem with both.

Best regards 

Patrick Ebert

[patoberli]

I'm checking now the ssid iPhone.
Things I suggest to change:
Session Timeout - increase to 8 hrs or even more (after the sessions times out the client must do a reauthentication = short outage)
Enable CCMK in the Security tab (faster mode for roaming for supported devices, you probably need to delete the ssid on the client and re-connect)

Otherwise I'd say it looks good (without checking every part of the configuration). One reason could also be bad coverage in corridors, if it happens while walking through one.
Based on the power readings of your APs, half of them seem to be manually configured to level 3 on 5 GHz. Are they this close to each other, or might that be a little to low? I think they sit very close to each other and it might be ok this way.

[Mikey Boy]

On the iPhone do they have wifi-assist enabled? I have seen issues with this in the past, it is generally the default option on them. If it is enabled I would test with it disabled and see whether the situation improves.

If it does improve, it is not necessarily a solution as it may indicate there are issues with the quality/performance of the wireless.

[patrickebert]

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@Mikey Boy wrote:

On the iPhone do they have wifi-assist enabled? I have seen issues with this in the past, it is generally the default option on them. If it is enabled I would test with it disabled and see whether the situation improves.

If it does improve, it is not necessarily a solution as it may indicate there are issues with the quality/performance of the wireless.

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Hello.

yes, we have already done that, it brought a significant improvement, but the abortions are still there.

[Mikey Boy]

If you disabled it and it improved things but did not completely resolve it you need to start looking at how that iPhone is seeing the wireless when the issue occurs.

If you have a specific area where the client will have this problem, take the iphone to this location and on the WLC issue "show client detail <mac address of client>"

You are looking at signal strength and SNR indicator. I can see that you have disabled the lower data rates which is normally best practice but has it been confirmed that that Iphone is happy with the current coverage to support this?

If you look at the log you attached a lot of the 5Ghz radios are reporting 8+ neighour APs at significantly higher RSSI than -67dbm, you are using 40Mhz wide channels as well. Have you confirmed that 40Mhz is actually offering any advantages over 20Mhz in the real world?