dmaTxLengthErrors - A non zero value usually indicates this switch port is at fault.
The dmaTxLengthErrors error itself is a mismatch between the length field and actual number of bytes transfered from the bus to the port buffer. The error usually indicates this switch port is at fault.
The dmaTxLengthErrors are caused by collisions. Each time if a port detects it then the count is incremented. The packet is eventually transmitted out. Of course, if there are excessive collisions, the packet will be dropped after so many retries.
