Rebuild of the sysplex-wide security associations structure (EZBDVIPA)

Rebuild can occur for several reasons:

Operator initiated
Loss of connectivity
Structure failure

After a rebuild, the EZBDVIPA structure is repopulated using local data from each of the TCP/IP stacks. Each TCP/IP stack is notified that a rebuild has occurred, and the structure must be repopulated. Each TCP/IP stack sends updated information about the security associations for DRVIPAs that it owns to VTAM® to be written to the EZBDVIPA structure.

During a rebuild, TCP/IP is not able to access the coupling facility. This creates a problem with obtaining sequence numbers. If TCP/IP cannot access the coupling facility, it cannot get the next available sequence numbers. Therefore, during rebuild, packets might be dropped and normal TCP/IP retransmit protocol will resend the data. It is assumed that rebuild takes on the order of 10-15 seconds, and the data is sent with the correct sequence number when the rebuild and repopulate have completed, so the connection is not broken. However, there are many factors which can affect the time for rebuild to complete, such as system load and number of structures being rebuilt. It is possible that connections might be dropped during such a rebuild. The situation is not likely, and it is rare that such a massive rebuild is required.