Unsolicited Router Advertisement

The SMF sends unsolicited router advertisement on successful PDU Session Establishment to share the allocated IPv6 prefix to UE. RA message is sent over the GTPU tunnel, which is created between SMF and UPF during the session establishment procedure. SMF also installs PDRs and FARs on the UPF to enable routing for RS and RA messages.

Router Advertisement Message Processing Call Flow
Note

The UPF cannot generate or send the unsolicited router advertisement to the UE as the IPv6 prefix allocation is performed by SMF.