18.104.22.168 Maintenance Timer Expiry
When the Maintenance Timer expires, the PNRP node MUST attempt to detect cloud splits (as specified in section 22.214.171.124.1).
If a node finds that it has no entries in its cache, it SHOULD also try to resynchronize with the nodes it knows in order to obtain more entries. Synchronization is initiated when the node sends a SOLICIT message, as specified in section 126.96.36.199.
The PNRP node MAY<6> also resolve any PNRP IDs that it wants in order to ensure that the cache requirements, as specified in section 188.8.131.52, continue to be met. If it does resolve, then the ResolveReasonCode MUST be set to REASON_CACHE_MAINTENANCE.