3.1.5.1 Receiving a Reliable Notify Message

When an Authenticated Internet Protocol peer receives a Notify message with RELIABLE_NOTIFY_FLAG set (as specified in section 2.2.3.5), it MUST send an acknowledgment consisting of a Notify message of type NOTIFY_ACK. The data of the Notify message is initialized to contain the sequence number from the Crypto header of the message being acknowledged.

After processing and acknowledging the notify, the recipient of the notify MUST NOT delete the MM SA until quick mode delete processing has been completed for all quick modes formed on this MM SA. The MM SA MUST NOT be used to establish any new QM SAs. Moreover, the QM SAs associated with the MM SA MUST NOT be deleted until deletion is triggered by other protocol events, as specified in [RFC2409] section 5.5. Once all the QM SAs associated with the MM SA have been deleted, the MM SA MUST be deleted.