This sets the alert period, in minutes, over which this port evaluates egress buffer overflow events affecting its VBR2 (variable bit rate, class 2) traffic before declaring a threshold-crossing alert. As the counterpart to VBR1's alert period, this lets this specific port's lower-priority variable-rate class tolerate a different, often longer, evaluation window before an overflow condition is escalated, matching VBR2's typically lower service priority relative to VBR1, ABR, and CBR. An admin might set this longer than pportATMTcaEBufOverflowVBR1AlertPeriod on this port to reflect that VBR2 traffic here is lower priority and brief overflow events are more tolerable before warranting an alert.