I've been pulling my hair out over a strange issue ever since swapping over to an Aruba controller-based solution at home, hoping someone has run in to this before & has some ideas.
Going 'all in' on the Aruba solution at home, I now have a virtual MM/MC deployed. The MC is running as my Internet gateway as well as as terminating the internal VLANs. For the most part everything is fine, no issues accessing the Internet/the other networks via the MC, and wireless is running well (one SSID broadcast, 5 IAP-215s). The only issue is wi-fi calling from Verizon, it works but repeatably cuts out roughly 45 seconds to 1 minute in to any conversation. My phone (iPhone) will recover from this with a brief 3-4 second loss of audio, but my wife's phone (Google Pixel) will just drop the call hard.
The default UDP timeout on the controller was set to something very short like 16 seconds so I upped that (the wi-fi calling basically does an outbound VPN to Verizon as I understand it) in case there was some sort of UDP timeout issue there but no such luck. Turned off DPI & all that on the controllers, no change. All the Wi-Fi calling WMM features were turned off too, with no change. Outbound UDP ports 4500 & 500 are open...clients that associate are all in the default 'authenticated' role so there shouldn't be any firewall rules preventing communication. I can connect to outside IPsec VPNs fine from a laptop with no packet loss, so I'm not sure what's different about the phone communication.
A packet capture didn't seem to show too much interesting between the phone & Verizon's servers, except for *one* ESP packet being sent from the phone with a TTL value of '1'. I still need to dig in to that.
No issues were present on my old setup (Cisco WLC & APs for wireless, Fortigate firewall for that side of things) so this seems to be a new issue with the MM/MC. I believe the software version is 8.7.0.0 but I'd need to double check.
Has anybody run across wi-fi calling issues before & resolved them?