Disconnect is viewed as a much longer loss of coupling facility access than rebuild. It is more likely that connections will be dropped during the first case. However, VTAM has automatic reconnect logic for cases 2 and 3 above, which might occur before the connections timeout.

When VTAM reconnects, it notifies each TCP/IP stack using the EZBDVIPA structure that a reconnect 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.