188.8.131.52 Boxcar Format
A Boxcar is formatted as an array of bytes that begins with a BOX_CAR_HEADER (section 2.2.1) structure and continues with one or more MESSAGE_PACKET structures, each of which is appended with its associated variable length data (if any). Each MESSAGE_PACKET structure in a Boxcar MUST be aligned on an 8-byte boundary. Because the size of each MESSAGE_PACKET structure is a multiple of 4 bytes (as defined in section 2.2.2), padding bytes MUST be added as necessary between the structures in order to have each structure aligned on a 8-byte boundary. Any necessary padding bytes can be set to any value, and MUST be ignored on receipt. The dwcMessages field of the BOX_CAR_HEADER structure MUST be equal to the number of messages in the Boxcar, and the dwcbTotal field of the BOX_CAR_HEADER structure MUST be equal to the total number of bytes in the Boxcar.