Exchange of syncronization data and metadata

Systems and methods that disclose alternative patterns for exchange of synchronization data and/or metadata, e.g., 'knowledge', to enhance performance of synchronization processes are disclosed. Accordingly, the innovation discloses synchronization mechanisms that employ exchange of data and metadata to alleviate a requirement of a complete 'round-trip' when synchronizing data. 'Knowledge' can be provided which informs a provider of data changes, modifications, additions or deletions. The 'knowledge' can lower expense and/or increase efficiencies of the synchronization exchanges by enabling informed decision-making related to enumerating changes within the synchronization processes.