Continuous, persistent IGMP statistics

In addition to collecting statistics on IGMP control traffic for currently active subscribers, devices that support this feature also collect and maintain cumulative and persistent statistics that account for both past and current subscribers. The device stores these statistics and copies them to the backup Routing Engine at a configurable interval, so this information is preserved across routing daemon restarts, graceful Routing Engine switchovers (GRES), in-service software upgrade (ISSU) operations, or line card reboots. Use the "continuous" option with the "show igmp statistics" command to view continuous statistics; without this option, you see default statistics only for currently active subscribers.