This Counter64 is the number of packets received on this endpoint just since the previous poll. It matters on an archived historical sample row of that same receive-counter set, kept purely for trending past intervals rather than showing the current live value because a rate calculated from this delta (packets per second) is the figure most monitoring tools alert on for a packet-rate storm, as opposed to a byte-rate storm. A totalPacketsDelta of 1,200,000 over a one-minute poll on the endpoint this history row belongs to is roughly 20,000 packets per second, well above what normal server traffic would generate and worth investigating as a possible broadcast storm.