This read-write field configures which CRC size, 16-bit or 32-bit, the switch should expect the customer premises equipment to generate for frames on this SMDS/DXI interface, so the switch's own error checking matches the CPE's actual framing. An admin must set this to match the CPE's actual configuration, since a CRC-width mismatch between the CPE and the switch will cause every frame to appear to fail integrity checking even though the data itself is fine. For example, if the connected CPE router only supports crc16 framing, setting lportSmdsCrc to crc32(2) instead would cause the switch to reject or mis-validate every frame from that device.