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New Member

Roam problems with 7920

Hi,

I'm having some problems with phone roaming. The equipment is wireless phones 7920 with firmware 7920.3.3-01-05 and callmanager v3.3.3. The security is made with LEAP and it's working fine.

The access points are configured in different channels. The ip helper address is correctely configured between the wireless and wired vlans.

When the phone roams, the authentication is done and the phone keeps indefenitely trying to register in callmanager and get stuck in IP Network configuration and finaly appears - no service ip config fail. The call keeps up but there is no sound and after some seconds the call finish.

It seems everything ok with AP configuration.

Do you have any idea to help to solve this problem?

Any fresh workaround ...

Thanks

Nuno

8 REPLIES
Cisco Employee

Re: Roam problems with 7920

Nuno,

This is likely a problem with DHCP and/or IP addressing. The "Configure IP Network" message indicates the phone is attempting to obtain an IP address from the DHCP server. The "No service-IP config. failed" message indicates that the phone failed to obtain an IP address from the DHCP server.

Seems like you may be attempting to roam at layer 3 (ie. across subnets, vlans). Keeping voice calls up when layer 3 roaming is not possible.

See the Wireless IPT Design Guide at:

http://www.cisco.com/warp/public/788/AVVID/wireless_ipt_guide_7920.html

Thanks,

Jordy

New Member

Re: Roam problems with 7920

Jordy,

It seems to be a normal behaviour (obtain IP address when phone roams) in a L2 environment. I found this statement on FAQ 7920 section:

"Q. Does the Cisco 7920 support Layer 2 roaming with active calls?

A. Yes, a Cisco 7920 IP Phone can maintain an active call when roaming between access points that have coverage for a single Layer 2 subnet, but calls are dropped when the phone roams into the access point coverage for another Layer 2 network.

When the Cisco 7920 roams into a different Layer 2 network, it drops the active call and then goes through the process of authenticating, associating, and obtaining a new IP address before it can register with the Cisco CallManager server again."

Thanks

Nuno

Cisco Employee

Re: Roam problems with 7920

Nuno,

Right, so you are roaming into another layer 2 network (thus the need to obtain a new IP address). Roaming to ANOTHER layer 2 network is the equivalent of layer 3 roaming.

As the FAQ indicates, you are able to keep a call active if roaming at layer 2, but if you change to ANOTHER layer 2 network, then you have to obtain a new IP address. In your case, this seems to be failing (given the 'No service-IP config. failed" message you are getting).

Thanks,

Jordy

New Member

Re: Roam problems with 7920

Hi,

of course, the "ANOTHER" makes the difference!

Are you aware about some instability with mobile phones 7920 roaming with c1200-k9w7-mx.122-11.JA ?

Some times access point gets confused and the problem is solved with a reload.

Thanks

Nuno

New Member

Re: Roam problems with 7920

Hi Nuno,

There's a new 1.06 version of firmware for the 7920, which solves some roaming issues. I'd try this first to see if it helps. You'll get it on CCO.

HTH

Bill.

New Member

Re: Roam problems with 7920

Hi,

I kept the 1.05 version on 7920 but upgraded the 1230 access points to c1200-k9w7-mx.122-13.JA1 and it seems to be fine!

Thanks by the support anyway.

Nuno

New Member

Re: Roam problems with 7920

Hello,

on the Networkers 2004, in "ACC-2013-7920-Deployment-Guide.pdf" is mentioned : (I can send you this docu if needed )

AP ---> 12.2.15JA (min)

7920 ---> Firmware min 1.07 better 1.08 (we opend a Case because roaming problems.) With 1.08 now the situation is better.

regards

Ulrich

New Member

Re: Roam problems with 7920

1.08 has many fixes including PER roaming triggers and dynamic RSSI and QBSS diff thlds. Highly recommended to only use the 1.08 image.

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