3.1.1.3.2.2 Property Value-Based Explicit Tables
When a specific object in the address book and a property on that object is specified to the NSPI server via the NspiGetMatches method, the server reads the values of that property and constructs a list of MIds based on a mapping between the values and other objects in the address book. This is not possible on all properties, only on those properties for which the server can establish a reference between the value of the property and some object in the address book. The NSPI Protocol does not constrain how a server establishes this reference. Clients can identify the properties that the server can map by attempting to obtain such a table. The server MUST return an error when it cannot make such a mapping (3.1.4.10).