Method of reducing bandwidth required for sharing of files on a server

1. A method of reducing bandwidth required for sharing a selected network-stored folder with a set of target computers so as to cause, on each target computer, storage locally of a mirrored folder that corresponds to the selected folder, each of the target computers coupled to a wide area network, wherein the selected folder is stored in a server-based storage system accessible over the wide area network, the server-based storage system coupled to a server, the method comprising:

causing, by the server, each target computer to run a synchronization program that has a synchronization protocol, the protocol configured in a given one of the target computers (i) to provide, over the wide area network, to the server, folder-change data when a mirrored folder stored locally on the given target computer has experienced a change by virtue of adding, removing, modifying, or moving a file therein and (ii) to interact with the server to cause updating of the selected network-stored folder to reflect the change;

in response to receipt by the server of the folder-change data from the given one of the target computers, transmitting, by the server, to the synchronization program running on the given one of the target computers, metadata from the server of the server-based storage system characterizing at least one destination IP address of the other target computers to be used for folder synchronization;

wherein the protocol is further configured to cause the given target computer to use the at least one destination IP address to cause its mirrored folder to be synchronized with the at least one of the other target computers by file transfer therewith over the wide area network on a peer-to-peer basis;

so that any need for transfer by the server of data files from the server-based storage system over the wide area network to the target computers in order to maintain synchronization of the selected folder is reduced.

2. A method according to claim 1 , wherein transmitting, by the server, metadata from the server characterizing at least one destination IP address of the other target computers, includes transmitting metadata characterizing destination IP addresses of all of the other target computers.

3. A method according to claim 1 , wherein the protocol is further configured to cause the file transfer on a peer-to-peer basis to be accomplished using encryption/decryption processes so each file transferred is encrypted before it is transferred and decrypted after being transferred.

4. A method according to claim 1 , wherein the protocol is further configured to cause each of the target computers receiving a file transfer from the given target computer to send to the server a synchronization-complete notification when such target computer's mirrored folder matches the state of the given target computer's mirrored folder.

5. A method according to claim 4 , further comprising, determining by the server whether a synchronization-complete notification has been received from each of the target computers other than the given target computer.

6. A method according to claim 5 , the method further comprising, if it is determined by the server that a synchronization-complete notification has not been received by the server from each of the target computers other than the given target computer, but that a synchronization-complete notification has been received by the server from at least one of the target computers, transmitting, to at least one of the target computers that sent to the server a synchronization-complete notification, metadata characterizing the destination IP address of at least one of the target computers that failed to send to the server a synchronization-complete notification.

7. A method according to claim 6 , the method further comprising, if it is determined by the server that a synchronization-complete notification has not been received by the server from any of the target computers, synchronizing the selected network-stored folder with at least one of the other target computers over the wide area network.

8. A method of reducing bandwidth required for sharing a selected network-stored folder with a set of target computers so as to cause, on each target computer, storage locally of a mirrored folder that corresponds to the selected folder, each of the target computers coupled to a wide area network, wherein the selected folder is stored in a server-based storage system accessible over the wide area network, the server-based storage system coupled to a server, the method comprising:

causing, by the server, each target computer to run a synchronization program that has a synchronization protocol, the protocol configured (i) to provide, over the wide area network, to the server, folder-change data when the mirrored folder stored locally has experienced a change by virtue of adding, removing, modifying, or moving a file therein and (ii) to interact with the server to cause updating of the selected network-stored folder to reflect the change;

in response to a share-folder message to the server from a given target computer to cause sharing, with a set of new target computers coupled to the wide area network, of the selected network-stored folder, causing each of the new target computers to run the synchronization program and sending, by the server, to the synchronization program running on the given one of the target computers, metadata from the server of the server-based storage system characterizing at least one destination IP address of the new target computers, to be used for folder synchronization;

wherein the protocol is further configured to cause the given target computer to use the at least one destination IP address to cause its mirrored folder to be synchronized with the at least one of the other new target computers by file transfer therewith over the wide area network on a peer-to-peer basis;

so that any need for transfer by the server of data files from the server-based storage system over the wide area network to the new target computers in order to maintain synchronization of the selected folder is reduced.

9. A method of reducing bandwidth required for sharing a selected network-stored folder with a set of target computers so as to cause, on each target computer, storage locally of a mirrored folder that corresponds to the selected folder, each of the target computers coupled to a wide area network, wherein the selected folder is stored in a server-based storage system accessible over the wide area network, the server-based storage system coupled to a server, the method comprising:

running on a given one of the target computers, a synchronization program, obtained from the server, that has a synchronization protocol,

in consequence of the synchronization of the protocol, (i) providing over the wide area network, to the server, folder-change data when a mirrored folder stored locally on the given target computer has experienced a change by virtue of adding, removing, modifying, or moving a file therein and (ii) interacting with the server to cause updating of the selected network-stored folder to reflect the change;

receiving, by the given one of the target computers, metadata from the server of the server-based storage system characterizing at least one destination IP address of the other target computers to be used for folder synchronization and using by the given one of the target computers the at least one destination IP address to cause its mirrored folder to be synchronized with the at least one of the other target computers by file transfer therewith over the wide area network on a peer-to-peer basis;

so that any need for transfer by the server of data files from the server-based storage system over the wide area network to the target computers in order to maintain synchronization of the selected folder is reduced.

10. A non-transitory digital storage medium encoded with instructions that, when loaded into and running in each of a set of target computers, each of the target computers being coupled to a wide area network, establishes in each target computer a synchronization program, the synchronization program having a synchronization protocol, wherein the protocol is configured to implement a method of reducing bandwidth required for sharing a selected network-stored folder with the set of target computers so as to cause, on each target computer, storage locally of a mirrored folder that corresponds to the selected folder, wherein the selected folder is stored in a server-based storage system accessible over the wide area network, the server-based storage system coupled to a server, the protocol configured in a given one of the target computers (i) to provide, over the wide area network, to the server, folder-change data when a mirrored folder stored locally on the given target computer has experienced a change by virtue of adding, removing, modifying, or moving a file therein; (ii) to interact with the server to cause updating of the selected network-stored folder to reflect the change; and (iii), on receipt, from the server, of a set of IP addresses of other target computers in the set of target computers, to use the set of destination IP addresses to cause its mirrored folder to be synchronized with that of the other target computers by file transfer therewith over the wide area network on a peer-to-peer basis; so that any need for transfer by the server of data files from the server-based storage system over the wide area network to the target computers in order to maintain synchronization of the selected folder is reduced.