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7921 constantly registering

guilhem.perez
Level 4
Level 4

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.

23 Replies 23

schunt
Cisco Employee
Cisco Employee

Hi,

We need more information regarding your issue.

What firmware are you running on the phone?

When you say it is "often registering", do you mean it is disassociating and reassociating with the AP or is it constantly re-registering with CUCM. Also, please provide information about your wireless environment.

Thanks,

Scott

Hi,

thanks for your reply.

The firmware is 1.0.4.

When I say they often registers, they dissaociate and reassociate unlike phone are not moving and they register unregister on callmanager.

While they are not register (sometimes a long time), it's possible to ping them from callmanager)

My wireless environment is composed by 23 Access Point without controller.

The security is 802.1x (AKM WPA with username and password). 1 ap is radius server.

I disable data rate lower than 11Mbit, 11Mbit mandatory and uper data rate enable.

I disable all channel not used on phone (let only 1 6 and 11).

I try lowering power on AP but I think it's not better.

I plan to do a site survey to check if there are interferences

Thanks

Hi.

Thanks for the information. Your idea of a site survey is a good idea to make sure that you do not have any interference. Make sure that you do not have any 2.4GHz phones in the environment. Let us know the results of your site survey.

Scott

Would suggest to look at the WLAN sniffer or 7921 log to see which side is sending the TCP reset.

If not 802.11 disassociation or roaming event, then no reason why TCP should be reset unless done via admin using CCMAdmin or if the device is not ACKing the SCCP packets from the CallManager either due to out of range, interference, etc.

Maybe you should open a TAC case to seek further assistance.

Hi all,

We have excactly the same kind of problems. We have 140x 7921G (FW 1.04), 8x 7920 (FW 3.02) and about 140x Cisco 12xx access points. No controller. Voice is separated to own VLAN. Switches are 2x 4506(L3) and the rest are 5x 3508 and >50x 2940,2950,2960. The phones get their addresses from DHCP. CCM is 4.1(3)SR4d.

The 7920's seem to work fine, but the 7921's do that re-registering process quite often. Also one-sided audio is sometimes a problem, along with the fact that if phone rings, you can't answer to it no matter what key you press...

When looking in the 7921G status messages, after it has re-registered, it says DHCP timeout. The thing is, that in the office, we have 3 AP's. For example, my workplace has signal strengths -50, -70, and -80. The phone seems to prefer to get the signal from the weakest -80 (only 1 bar of signal strength). Even if the -50 AP has only few clients associated to it.

I guess there could be something wrong with the Firmware 1.04. I THINK that we didn't have those problems with 1.03. However, I would not like to revert back to 1.03, because it had some bug, that is quite critical to our system (and it was corrected in 1.04)

-Sami

No known issues in this area with 1.0.4, so would tend to point to RF or network related.

Open a TAC case if you need further assistance.

Good evening,

I' m having the same kind of problem.

My scenario is:

- n. 20 7921G firmware version 1.0.4

- Access Point Symbol

- separate Vlan for Voice

My problems are:

- very often Wireless Ip Phones register

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

With version 1.0.3 there wasn' t this kind of problem ?

Some more informations:

- ping to Wireless Ip Phone when is not in connection is about 1.000 msec

- ping to Wireless Ip Phone whes is in connection is about 10-15 msec

Marco Parmigiani

Hi,

I've opened a TAC Case,

I'll let you know the evolution of this issue

Thanks a lot,

did you try to downgrade to version 1.0.3 ?

not yet,

I read there are some important bugs

but I think I will try as soon as I have time to do it in ly lab.

Hello again,

Just to provide some more information about our system... We don't have any authentication or encryption in our voice-VLAN (only hidden SSID). They are used in underground mine. That also rules out any RF-pollution from other sources... The network should be more than ok. Standard Cisco equipment with spanning-tree and all that. The overall network utilization is quite low.

Also the fact that the older 7920's work extremely good - no problems at all, suggests that there could be something firmware-related problems.

-Sami

Wouldn't jump to conclusions so fast without evidence.

The 7920 and 7921 are totally different devices. 7921 has WMM, CAC, OFDM support, many differences.

drees
Level 1
Level 1

Did you get this resolved? I'm having the same problem with a new installation, four autonomous 1242AG access points with 7921 phones. They drop their registration from CCM and one of the phones won't get an IP address, but works intermittently with a static IP. Signal strength and SNR values are great, but phones still have registration issues with CCM. We've tried fw 1.03 and 1.04 with no change.

Just wondering if you found a resolution or a direction for troubleshooting.

Thanks.

Dave

not yet still have the case open

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