Resuming a Previously Interrupted Peer-to-Peer Synchronization Operation

A method of synchronizing data between two devices, the method comprising:

• upon initiation of a current synchronization operation, determining whether a prior synchronization operation between a first device and a second device was successful based on a value of one or more indicators in the first device;
• if the prior synchronization operation was successful, identifying a first data set comprising changes to multiple different data elements in the first device that have occurred since the prior synchronization operation, and if the prior synchronization operation was not successful, identifying a second data set comprising changes to multiple different data elements in the first device that have occurred since an earlier successful synchronization operation for which separate acknowledgements were not received during the prior synchronization operation;
• sending the changes in the first or second data set to the second device;
• receiving one or more separate acknowledgments from the second device, each separate acknowledgement indicating that the second device successfully applied a specific change in the first or second data set;
• when an acknowledgment has been received for each of the changes in the first or second data set, modifying the one or more indicators to indicate that the current synchronization operation has completed successfully.