Each NSPI server MUST have at least one unique GUID, used to identify an NSPI session (section 18.104.22.168). The server MUST acquire this GUID before it is prepared to respond to NSPI Protocol methods. The protocol does not constrain how a server acquires this GUID. The server MUST maintain this GUID for the duration of an NSPI session. Although the protocol places no further boundary or requirements on the time period for which the server maintains this GUID, it is recommended that implementations maximize this time period to improve the usability of the NSPI server for clients.
Each NSPI server maintains a set of address book objects and containers, according to [MS-OXOABK]. The NSPI Protocol does not constrain how an NSPI server obtains its initial data set, nor does it constrain the contents of this initial data set. How an NSPI server obtains this data is an implementation-specific detail.