This object is how long, in milliseconds, the cookie exchanged during this association's four-way handshake remains valid. If the far end is slow to complete the handshake, for example under heavy load, and this value is set too short, the cookie can expire before COOKIE-ACK arrives, forcing that association's setup to restart from INIT, visible as repeated failed handshakes to that specific peer. At the recommended 60000 milliseconds, a peer taking 45 seconds to respond during setup would still succeed, but one taking over a minute would see its handshake fail and have to start over.