Problem VoIP client roaming

[slandeira]

Hello,
I have a problem with roaming between wireless antennas since phones 7921. The phone does the roam between APs when it reaches a -78dB threshold at which the call is cut or degrades much.

In our network VoIP over WLAN we have: 802.11b / g; WLC 2112 (ver.6.0.196.0), 12 access points LAP1131G and phones.

How can do to make the decision to roaming occurs before coming to degrade the call?
My values in "Roaming Client Section" are:

RF Parameters

Mode  Custom 
Minimum RSSI       -80 dBm 
Hysteresis              2  dB 
Scan Threshold      -72 dBm 
Transition Time       5 Seconds

Thanks.

Susana.

[slandeira]

How I can change the decision threshold roam in phone 7921?

[George Stefanick]

First, do you have a voice grade network ? Your wireless edge should be -67 for voice by this i mean if your phone is reading higher then -67 anywhere you are outside of voice coverage.  You cells should have a 20% cell overlap.

As for the phone, what code on are you on again?

[Jeremiah La Tour]

The 7921 and 7925 phones do not use the WLC's roaming settings. The roaming decisions are made internal to the phones firmware.