Can you describe how ISAKMP and IKE protocols work?

"ISAKMP defines the procedures used in a VPN. These include authenticating a peer attempting to communicate, creating and managing Security Associations (SA), key generation techniques, and mitigating denial of service and replay attacks. As a framework, ISAKMP typically utilizes IKE for key exchange. IKE is a two-phase protocol that generates a session key, protects the communication using algorithms, authenticates peers, and negotiates the second phase of the communication. In Phase 2, IKE establishes the SA. The three modes used by IKE include Main and Aggressive for Phase 1 and Quick for Phase 2. When Phase 2 negotiations are concluded, two unidirectional IPsec SAs are established, one for sending and one for receiving encrypted data."