IKE fragmentation uses the following timers:
Fragmentation timer (for each IKE message): This timer triggers fragmentation. The fragmentation timer MUST be started after sending each IKE message. The expiration of the fragmentation timer indicates that the message will be fragmented the next time it is retransmitted. There MUST be one fragmentation timer per MM SA. The fragmentation timer must fire within the retransmission duration of the IKE negotiation and SHOULD<16> be between 1 and 5 seconds.
Fragment reassembly timer (for each Fragment ID value): This timer MUST trigger the discarding of all the fragments received for this message. The fragment reassembly timer MUST be started when a Fragment payload is received and the timer has not been started for the corresponding Fragment ID value. When the fragment reassembly timer fires, the delay MUST NOT exceed 90 seconds.<17>