This read-only Unsigned32 value, expressed in minutes (range 1..65535), gives the configured length of the accumulation window for the most recently completed short-interval historical bin in this IGMP snooping/proxy PM table. Admins use it to normalize the raw counters in this bin into a rate — for example dividing a byte counter by Duration — when comparing a bin that closed early to one that ran its full length, since it is the metadata field for the most recently completed short-interval historical bin in this IGMP snooping/proxy PM table. For the most recently completed short-interval historical bin in this IGMP snooping/proxy PM table, this typically reads 1440 (minutes), which an admin uses to divide a Counter64 total in the same bin into a per-minute average when comparing it to a shorter or longer bin elsewhere in the table.