[cisco-voip] 7921G suffering from dropped calls while roaming between AP

[Jason Aarons (US)]

I would encourage long term moving to the A band, it has more non-overlapping channels with less pollution/interference. Given that you should plan/site survey for 5Ghz. I would look into AutoRF to verify you don't have any channel/power problems. If you want to stick with the 2.4GHz b/g I would consider looking at Cisco CleanAir where the silicon/asic has built in spectrum analysis.

I would put a laptop on the 7921 SSID and use IP Communicator and test if you can roam, do you have multiple controllers? Did you use the WCS to audit they are setup identical?

There were firmware bugs with 1.3.4, change the load to 1.3.4sr2 or 1.4.1 or latest sccp load
Unified Wireless Deployment Guide
http://www.cisco.com/en/US/docs/voice_ip_comm/cuipph/7921g/6_0/english/deployment/guide/7921dply.pdf

Windows 7 netsh command line and Network Monitor 3.3 have some ways to debug the wireless client;

For example, to start a trace for the WLAN scenario, create a CAB file with a formatted report, capture network traffic, and store the files with the name WLANTest in the C:\Tshoot folder, the netsh command is netsh trace start scenario=WLAN capture=yes report=yes tracefile=c:\tshoot\WLANtest.etl

Then use the free Microsoft Network Monitor 3.3 or higher to view the .etl file

http://forum.persianadmins.ir/showthread.php?p=48918

Other netsh commands;
netsh wlan show networks mode=bssid
netsh trace show status
netsh show wlan all
netsh wlan show interface

Microsoft Network Monitor 3.4 download
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=983b941d-06cb-4658-b7f6-3088333d062f&displaylang=en#SystemRequirements



From: cisco-voip-bounces at puck.nether.net [mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Ki Wi
Sent: Tuesday, January 25, 2011 6:05 AM
To: Cisco VoIP List
Subject: [cisco-voip] 7921G suffering from dropped calls while roaming between AP

Hey guys,
I need a little help here. We have lots of newly provision 7921G in the environment running ver 1.3.4. WPA2/AES/LEAP/CCKM turned on. WLC is on latest 7.0.98.0. The LAN switches are mostly on 2960S or cat4500 with sup6lite.

I have read around but doesn't really find much information on how to troubleshoot this issue. I'm aware that 7921G with version older than 1.3.4 will need to do full reregistration when it roams to the new AP and some roaming issues with older sup engine.

My colleague actually troubleshoot this issue and he changed the wireless phone to scan for channel 1/6/11 only (on b/g) , we disabled the A as it seems like we have a poor coverage with 802.11a. Customer reported that they tested with 2 phones (one with new setting , one with existing setting), the phone with new setting doesn't suffer any dropped calls at all. I find it too amazing to believe so I'm wondering does anyone have similar experience before? We have other large sites which doesn't suffer this issue. Honestly, I don't think that's going to be the solution as it requires us to drill down into low level configuration and manipulate how the phone to scan for AP in specific channels.

Cheers,
Ki Wi


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