This 4-byte octet string captures the DXI2 header of the last SMDS PDU that triggered the 'Dxi2 Cr Invalid' violation, meaning the Command/Response (C/R) bit or field in the DXI level-2 header held an unexpected value for this port's role. An admin decoding these 4 bytes can see exactly how the offending header was framed, useful for spotting a CPE that's sending frames as though it were the network side (DCE) when it should be behaving as DTE, or vice versa. For example, a misconfigured DXI adapter set to the wrong DCE/DTE role would repeatedly generate this violation with the C/R bit set inconsistently with the port's configuration.