This counts packets dropped because of a bad IP header checksum. Because this is a checksum failure on the header itself rather than the payload, a rising count here points at data corruption occurring somewhere between the sender and this modem, possibly related to the same physical-layer issues that would also show up as CRC errors in cdmipEtherReceiveCRCErrorFrameCount if the corruption is happening on the local Ethernet segment. A rise in this counter that tracks closely with a rise in cdmipEtherReceiveCRCErrorFrameCount would suggest a shared root cause, likely a noisy cable or failing transceiver corrupting frames before the IP header checksum is even validated.