We are running an installation with about 200 nokia dual mode phones and the ICC skinny client. We installed the first 4 floors of our building with 1131AG LAP's and a couple of 4402 WLC's.
Problems started when we installed the 5th floor with 1252 AP's. Data performance was OK, but voice problems caused a riot with my users. Strange thing is, the couple of 7921's that we use are having no problems at all. The 802.11g band, which is the busiest, is the only one having problems.
There a couple of things I already tried:
- upgrading to 4.2.130
- reducing the number of AP's to 3 per floor, so less co-channel interference problems can arise
- switching off all 802.11n support
- changed the Transmit Power Threshold to -75 dBm
At the moment I worked around the problem by replacing the 1252's with 1131's, but that leaves me with a slower network and an unsolved mystery (and a couple of dust eating 1252's)
Anyone else using a comparable setup and sharing the same problems?