IS-10 defines behaviour for:
This specification is dependent upon accurate time synchronization between all system components.
Authorization Servers, Resource Servers and Clients (or the hosts which they are deployed onto) MUST be capable of synchronizing their clocks to an external source of time. It is STRONGLY RECOMMENDED that Network Time Protocol (NTP) is supported for this purpose.
Deployment environments SHOULD include one or more providers of time synchronization data matching the requirements of any chosen Authorization components.