Cisco 8821 Audio Drops / Packet loss

[florian.hanig1]

Hello,

I've a Cisco 2504 WLC with SW: 8.5.161.0 and Cisco 3802I Access Points.

The AP's are running in local AP Mode.

My Cisco 8821 Phone is on SW: 11-0-5SR3-2.

I've done the Configuration of WLC with the Cisco 8821 Deployment Guide.

(https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/cuipph/8821/english/Deployment/8821_wlandg.pdf)

All recommendations are set on WLC Software.

I have some very little Audio Drops and Voice Packets loss...

I've tried my tests with 2 meters away from the AP.

What can I do ?

[Leo Laohoo]

If this issue only appears on 11.0(5)SR3 then I'd consider downgrading to 11.0(5)SR2.

[florian.hanig1]

This issue appears on 11.0(5)SR2, too....

[Leo Laohoo]

When this issue occurs, does the phone lose wireless connectivity?

[florian.hanig1]

No, phone is always connected.

The drop is only a little less than one second... 

[florian.hanig1]

Hi,

unfortunately I still haven't found a solution after such a long time...

Out Cisco 8821 are on the newest Firmware Release, WLC is on newst Firmware Release.

I've checked everything in the 8821 Deployment Guide a number of times, but found no solution.

Now I've done some Packet Captures with Wireshark.

I've mirrored the Port to the Wlan-AP and see that there are missing Sequence Numbers, during the calls.

(From Phone TX), RX Side (to phone) is always okay...

While I do this, the 8821 phone is right next to the Access Point !!

Any suggestions ?

[Leo Laohoo]

Let us eliminate a handset as the issue. 
Can you replicate this issue on one or two other handsets? 

Do you have a 7925G WiFi handset?

[florian.hanig1]

No, but i can look for a 7925g Wifi handset to test.

But I've tested with many 8821 handsets.

Can it be, that the AP's are in local Mode is the Problem ?...

So the Traffic goest from Phone over Wifi to AP, AP sends the traffic to WLC over CAPWAP Tunnel and the WLC sends it to Voice VLAN...

Maybe this is the issue ?

But the 8821 Deployment Guide do not say, that's not permitted to use AP local Mode in WLC...

[Leo Laohoo]

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@florian.hanig1 wrote:

But I've tested with many 8821 handsets.

---

Good, so skip this and go and test it with a 7925G.

[florian.hanig1]

Hey Leo,

I've tested with 7925G Handset and all is fine..

But I've many many different 8821 handsets that all have this issue. But that can't be a hardware issue...

[Tony Rosolek]

Did you find a solution for the described problem?

[florian.hanig1]

No... 

Any ideas to fix ?

[Leo Laohoo]

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@florian.hanig1 wrote:

But that can't be a hardware issue...

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@florian.hanig1, you've already answered the your question.  

[florian.hanig1]

My question is how to fix this problem.

It is not a Hardware issue, because 7925G Phone work good, and all 8821 phone have this problem.

We've more than 20 phone from different charges...

[Leo Laohoo]

The problem is the 8821.  

No one from Cisco is going to admit it but the 8821 takes the crown as the worst WiFi phone in the market today.  Do not get me started about the hardware design bugs/fault but software bugs, particularly when the phone goes out-of-range (from WiFi) are plenty (like CSCvn81608) and they remain unfixed. 

When the phone goes out-of-range, there are no visual indication that this has happened.  The phone simple do not want to join the WiFi.