Xfinity IPv6
AT&T requires you create a IAPD for each of the subnets that are brought down from the Gateway.  Xfinity only requires one IAPD
The first network on Xfinity isÂ
::94f3:92ff:fe55:8f98/128
Second network would have ::1:<mac address in EUI-64 format>
Same IAI number and WAN port
::1:94f3:92ff:fe55:8f99/128