This read-only Gauge32, measured in milliseconds and noted as superseded by cVideoCommonStatsHistoryTxMaxDelay, records the peak one-way delay measured during the entire completed call session. An admin uses this to identify whether a finished call experienced a delay spike severe enough to have caused noticeable lag for the participants. A max delay reading well above typical WAN latency for that route would tell the admin to check for a routing or queuing problem along that call's path.