1. According to ETSI TS 129 118 4.1, if the Network Access Mode (NAM) is set
to "Packet only," no SGs association should be established.
2. If the NAM is set to "Packet and Circuit," and the SGs association is
rejected by the CS core, this rejection should only impact
the SGs association itself and not result in a UE attach rejection
for a UE with a valid HSS account.