One-way audio is typically a network problem, not a VoIP problem. Can you source-ping the destination phone from the default gateway of the wireless subnet your iPhone is on? If yes, you may want to run a quick packet capture on the WLC to ensure the client is sending the RTP packets (this is unlikely to be the problem though).
One other thing to check is to ensure that the 200 OK SIP message to the iPhone has the correct SDP information, namely the correct IPv4 address of the phone. This should be pretty straight forward unless there is NAT going on.
Lastly, keep an eye out of Layer7-aware firewalls (e.g. ASA) in the traffic path. It is possible they are manipulating the SIP/SDP messaging.
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The short answer is that you don't.... That isn't entirely true while at
the same time it kind of is, but for the most part you don't configure
the softkeys. You enable or disable them via TCL. Here is the long
answer. Be sure to read the whole thing or e...
Topology: IP Phone > Switches > Microsoft NPS setup to forward 802.1x
proxy to > ISE 2.1 patch 3 Authentication: EAP-TLS using Cisco MIC SANs
Phone Models 802.1X support? 802.1x flavor Addtl Comment EAP-MD5 EAP-TLS
Cisco 3905 Y Y N Cisco 6911 Y Y N Cisco ...