Cisco CP 8821 Call drops and audio issues on a stable Wi-Fi

[h.matsalia]

Hi, 

We are having troubles deploying Cisco CP 8821 wireless phones. In our test environment, we have configured wireless profile for one SSID and one wireless profile group, which we have added to the phone profile for the CP 8821. The phones are well registered on the CUCM and they have picked the SSID defined in the wireless profile. But the wireless phones can't call each other, the call keeps dropping but when you call the deskphone the call goes through but the voice is one way. The one on wireless can't hear the one on deskphone but the one on deskphone can hear the one on wireless. The wireless can call the deskphone but when the deskphone calls the wireless the call also drops.

CUCM 14, Deskphone CP 7821, All the phones (SIP) running the latest firmware. 

If someone can advise on how I can reslove this I will really appreciate.

[JaysonRCCL]

Did you follow all the settings on the WiFi per the Cisco 8821 Deployment Guide?  You made need to contact support at the wifi vendor D-Link.

[h.matsalia]

Yes.. I don't have any issues with the AP, I can do the two frequencies 2.4GHz and 5GHz. For the phones I have assigned SSID on 5GHz as the default set by Cisco in Auto option.

[Jonathan Schulenberg]

Absolutely agree with others that you should update to SR5 but no-way or one-way audio likely isn’t a phone issue. The AP, or some other device in the network path, is interfering. Firewall blocking traffic is the most likely since NAT on an internal network is far less common. You may need to span a port one hop at a time to see where the RTP packets stop.

Once you get past that, the Deployment Guide that @JaysonRCCL referenced should be required reading here. Voice over WI-FI is really challenging to do well. It requires an active survey, a lot of tuning, and an excellent wireless engineer.

[BalajiSivaraj49175]

Here are some things you can try if you're having one-way audio issues with your Cisco 8821 wireless phone:
Check your audio settings
Go to Settings > Admin settings > Diagnostics > Audio. You can also try setting the headset sidetone to "High" in Settings > Phone settings > Sounds.
1.Check your speaker phone
Make sure the speaker phone is off, which means there shouldn't be a speaker icon next to the wireless signal indicator. You can also try confirming that the earpiece and/or headset play audio.
2.Check your network
Make sure IP routing is enabled on the Cisco IOS gateway and routers. You can also try verifying the media termination point configuration and binding the H.323 signaling to a specific IP address.
3.Update your firmware
Running the latest image (11.0(6)SR2 or later) can fix issues like one-way audio. If you're still having trouble, you can contact Cisco TAC.

[h.matsalia · Accepted solution]

Hi Guys,

I managed to resolve this. The problem was the Access Point. We were using a layer 3 AP which was having its own DHCP pool. I connected a layer 2 AP and everything is working perfectly, all calls going through and the voice is also very clear.