Each server MUST have at least one unique GUID, used to identify an NSPI session, as specified in section 184.108.40.206.1. The server MUST acquire this GUID before it is prepared to respond to Exchange Server 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 server for clients.
Each server maintains a set of Address Book objects and containers, as specified in [MS-OXOABK]. The Exchange Server NSPI Protocol does not constrain how a server obtains its initial data set, nor does it constrain the contents of this initial data set. How a server obtains this data is an implementation-specific detail.