This read-only 64-bit counter tracks the number of bytes marked red, meaning non-conformant, under the currently selected Conformance Counter Set for this group. Admins monitor it to quantify how many bytes under a specific conformance profile are treated as out-of-profile and likely discarded, informing decisions about tightening or loosening that profile's rate parameters. For example, if nbTcGroupReslConfRedOctets rises sharply after applying a new conformance set, the admin may need to raise that set's rate limits to avoid dropping legitimate traffic.