Instrument blocks provide information about entities in the FIX messages.
Each supported FIX message type contains at least one instrument block that provides information about the entity for which data is present in the message. Some messages can contain information about multiple instruments. In general, the Symbol or Security ID fields of the instrument block map on to the stock symbol of the corresponding RAP table, and this is used to automatically look up instrument IDs in the instrument table. The lookup is completed via the RDS template mechanism.
A default value for lookup table failures must be specified in the template.