184.108.40.206.1 Large Read Support
If the CAP_LARGE_READX bit is set in Client.Connection.ServerCapabilities, then the client is allowed to issue a read of a size larger than Client.Connection.MaxBufferSize using an SMB_COM_READ_ANDX request. Otherwise, the client MUST split the read into multiple requests in order to retrieve the entire amount of data.<90>
If a large read is being issued and the object being read is not a file, then the count of bytes to read MUST be placed into the MaxCountOfBytesToReturn field. This field is a 16-bit unsigned integer; therefore, the maximum count of bytes that can be read is 0xFFFF bytes (64K - 1 byte).
If a large read is being issued and the object being read is a file, then the two least significant bytes of the count of bytes to read MUST be placed into the MaxCountOfBytesToReturn field and the two most significant bytes of the count MUST be placed into the MaxCountHigh field.