ISAKMP Phase 1: The first phase is a “setup” stage where two devices agree on how to exchange further information securely. This negotiation between the two units creates a security association for ISAKMP itself; an ISAKMP SA. This security association is then used for securely exchanging more detailed information in Phase 2. ISAKMP Phase 2: In this phase the ISAKMP SA established in Phase 1 is used to create SAs for other security protocols. Normally, this is where the parameters for the “real” SAs for the AH and ESP protocols would be negotiated.
