Optimize VoIP - USG Flex

Ecari

I have a problem with a customer equipped with a USG Flex 200 who makes phone calls over Wifi. It doesn't work on iphones, no problem on Android.
Is there an option to optimize VoIP flows from a USG Flex 200 (in particular the LLDP option which I can't find).

Thanks for your feedback

Zyxel_Melen

Hi @Ecari,

Could you help check your log that if there are any blocking logs first? We assume there might be a security service/policy that blocks VoWiFi from iPhones. You can filter the iPhone's WiFi IP address to check.

Update:

Please check the security policy to see if it allows UDP 500, UDP 4500 for Wi-Fi calling/VoWiFi, and UDP 16384 - 49327 for RTP.

Zyxel_Melen

Hi @Ecari,

I would like to confirm something with you first:

1. Do the iPhone users apply the VoWiFi function from their service provider?
2. Does the iPhone enable the VoWiFi function?

Ecari

Yes, of course! I've activated LLDP on the access points, but I can't find an equivalent option on the Zywall USG Flex 200.

Zyxel_Melen

Hi @Ecari,

Could you help check your log that if there are any blocking logs first? We assume there might be a security service/policy that blocks VoWiFi from iPhones. You can filter the iPhone's WiFi IP address to check.

Update:

Please check the security policy to see if it allows UDP 500, UDP 4500 for Wi-Fi calling/VoWiFi, and UDP 16384 - 49327 for RTP.