7921 constantly registering

[guilhem.perez]

Hi,

I've a problem with IP Phone 7921 which are often registering.

I've no WLC and use WPA LEAP.

I suppose it's a roaming problem?

Thanks.

[asafayan]

We have a 15 WLC (4.0.217.0), 600 APs, 300 7921 (1.03) and utilize EAP-FAST.

We intermittently have single digit audio delays that often occur at the beginning of calls, and also occur during the middle of calls and phones that spontaneously unregister/re-register.

Any suggestions to improve these symptoms would be much appreciated!

TIA

[mparmigiani]

Hi,

it' s two days that Cisco IP wireless phones 7921G are working fine. I've Symbol AP, not Cisco AP.

My initial problems:

- very often Wireless Ip Phones register

- very often customer receive ring and is not able to answer (using green botton or answer button or other button)

After some modifications where we solved theese two points there was yet another problem:

- when user answer, he has to wait 1/2/3 seconds or more to hear voice.

The final solution was:

- downgrade Symbol WS 5100 from version 3.0.2 to version 2.1.2

- Used ACS (Automatic Channel Selection) to determine the best channel selection for AP and fixed them

- Modified DTIM parameter from 10 to 2 (I think this parameter solved the late start of voice stream)

- Enabled only 1 2 Mb basic and 5,5 11 Mb supported frequency (if everything will work I'll try to enable 36 and 54 Mb).

- 80% Bandwidth for Wlan VoIP and 20% for Wlan Data

- Access point restart

I hope this help for you.

Bye

Marco

[mparmigiani]

Hi,

and I modified on 7921G following parameter:

- Mobility Power saving to Nothing (default U-APSD/PS-POLL).

Bye

Marco Parmigiani

[migilles]

Yes just received word from another customer they are seeing buffer overflows when using PS-POLL with the Symbol WLC w/ just a few 7921 clients associated.

Symbol doesn't support U-APSD.

So until Symbol can address this issue, the workaround is to put the on call power save mode to "None", where the phone will use active mode when on call.

Will still use PS-POLL when in idle though.

Granted this is not a good workaround as then the users may start to complain of poor battery life. Should expect to get about 50% of the advertised talk time (10 hours for standard battery), so looking something like 5 hours, which is much like the 7920 phone.

[migilles]

Upgrade to 1.0.4 and ensure that RTP packets are being marked as DSCP = EF to the AP.

For more info see the 7921 design guide @ http://www.cisco.com/univercd/cc/td/doc/product/voice/c_ipphon/english/wip7921/7921dply.pdf.

[g.rienstra]

HI,

Is your issue resolved? i havethe same issue!!

One way speech, reregistering etcetc. I do suspectthe firmware. changes in QOS and USD-poll did not resolve mij problem..

Please let me know.

Cheer.

Goen

[dytechitsolutions]

Has anybody a solution for this Problem?

Our Customer has a UC540 SW-Pack 8.2 and two AP541n & two 7921G FW-1.4.2 phones.

The 7921G has  a lot of problems in this environment - we open a TAC and the SE said we must disable all other VAPs on the 541n AP. This helps for the problem to answer a call. But the phones register and unregister all the time, and this is no stable solution. We change Keepalive to 10, and try to disable the Moh - without any changes.
Furthermore this is no Solution, to disable all other VAPs then for the VoIP-Vlan.

It is realy urgent! The custumer is very angry about several different problems with the 7921G phones and the many bugs with the current firmware of the UC.

Thanks
Albrecht

[migilles]

Have you provided WLAN sniffer traces to TAC to analyze to see what is causing the frequent deregistering?

Also is this deregiatration from CME or disassociation from the AP?

Sent from Cisco Technical Support iPhone App

[dytechitsolutions]

The 7921G has a good WiFi access. About -35 to -45 RSSI. The problem might be a problem with the AP541N because if i disable the AP and enable the AP of the UC540 it works. But the UC540 is insight a Rack and the WiFi is not huge for the enviroment. So we disable the UC540 WLAN an add two AP541N.

I will use a WiFi sniffer today an provide the analyse to TAC. But in my opinion this is a problem with 541N.

050280: Feb 12 14:23:18.028: %IPPHONE-6-REG_ALARM: Name=SEPC89C1DXXX Load=CP7921G-1.4.2 Last=TCP-Zeitüberschreitung

050281: Feb 12 14:23:18.236: %IPPHONE-6-UNREGISTER_ABNORMAL: ephone-12:SEPC89C1D92339E IP:10.1.1.22 Socket:4 DeviceType:Phone has unregistered abnormally.

050282: Feb 12 14:23:18.240: %IPPHONE-6-REGISTER: ephone-12:SEPC89C1D9XXXX IP:10.1.1.22 Socket:7 DeviceType:Phone has registered.

Thanks

Albrecht