When a VTAM® node fails, all TCP/IP stacks using that VTAM node to access the EZBDVIPA structure lose access to the structure, and the VTAM node is disconnected from the EZBDVIPA structure. When VTAM is restarted, the TCP/IP stacks that were using that VTAM node re-register as EZBDVIPA users with this VTAM and VTAM attempts to reconnect to the EZBDVIPA structure. When the reconnect is complete, VTAM notifies the TCP/IP users, and the TCP/IP stacks repopulate the EZBDVIPA structure with updates to the IPSec security associations that have changed while VTAM was down.