188.8.131.52.3 Strict NDR/NDR64 Data Consistency Check
These extensions update the DCE 1.1: RPC Specification [C706] by specifying that, during unmarshaling, invalid octet streams SHOULD be rejected by enforcing a set of rules referred to as strict data consistency checks. All the consistency check rules specified in the following sections are also applicable to NDR64 transfer syntax. This is often referred to as robust check.
The consistency checks are grouped into categories called target levels. The two target levels are target level 5.0 (as specified in section 184.108.40.206.3.2) and target level 6.0 (as specified in section 220.127.116.11.3.3). Target level 6.0 is a strict superset of target level 5.0.
A consistency check is the act of ascertaining a certain relation between two or more values in the octet stream inside an implementation of these extensions. If the relation is true, the consistency check MUST be regarded as passing. If the relation is not true, the consistency check MUST be regarded as failing. The set of consistency check rules follow, and correlation validation is the most important one.