This read-only value reports the Phase Two security association's lifetime expressed in kilobytes of traffic, an alternative rekey trigger to the time-based lifetime. An admin reads it to know the data-volume threshold that will force the tunnel to renegotiate keys, regardless of how much time has elapsed. For example, a value of 512000 would mean the SA rekeys once 512,000 KB of traffic has passed through the tunnel, whichever comes first against the time-based lifetime.