This read-only counter holds the high-word of the count of bytes permitted by this interface, meant to be combined with ccarStatSwitchedBytes for a full 64-bit total once the byte count exceeds 32 bits. Like its packet-count counterpart, this high-word only matters once ccarStatSwitchedBytes itself has wrapped past 32 bits, about 4.3 GB of permitted traffic, and it exists specifically because CAR predates 64-bit SNMP counters, requiring manual combination of the two 32-bit values by the polling manager. A high-bandwidth interface passing tens of gigabytes of conforming traffic per day would wrap ccarStatSwitchedBytes multiple times daily, making this overflow object essential for computing an accurate daily total.