DIME is a specification for packaging records together. DIME has the ability to capture binary information. It also uses a fixed-length header and pre-identified record lengths, enabling random-access to the record of choice.

Messages that are DIME format can be attached to a SOAP call via the WS-Attachments specification.

Many view DIME as a successor to MIME-multipart. It’s ability to utlize fixed-record lengths to jump ahead is faster than MIME’s use of a separator (which needs to be parsed for).

From Microsoft:
“DIME is a packaging mechanism that allows multiple records of arbitrarily formatted data to be streamed together. Records are serialized into the stream one after the other and are delineated with an efficient binary header.
The first record in a DIME message has the MB (Message Begin) flag set in the header and the last record has the ME (Message End) flag set. The header also includes a fixed length-portion that allows for the easy computation of the absolute length of the record. Determining record lengths in an efficient manner is important for quickly moving from one record to the next in the data stream.”

Here is the Internet draft for DIME.