This read-only Integer32 reports the byte-count limit, in kilobytes, after which the IKE Phase 1 security association with this peer must be renegotiated. It gives admins the volume-based counterpart to the time-based lifetime, useful for high-traffic tunnels where data volume triggers rekeying before the timer would. For example, a value of 100000 means the SA is renegotiated once 100,000 KB of data has passed, regardless of elapsed time.