JP2003099337A - Data-shareable device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the convenience of users by letting other devices automatically take over services, when a downloading in progress is stopped. SOLUTION: This device is a data-shareable device for constituting a service group sharing data between devices connected with each other through a network. In addition, a data-transmitting means 12a for transmitting data to other devices and a replica registering and referring means 14a which registers and refers to the replica of data are provided. When new data are produced by the device in the service group concerned, the replica of the new data is produced and registered by the replica registering and referring means 14a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage device, a personal computer (P
C), servers, set-top boxes for specific purposes,
Not only for consumers but also for a wide range of digital contents.

Recently, personal computers have become widespread, and high-speed LAN (Lo
cl Area Network) 100Mbps is commonplace and 1G
Ethernet (registered trademark) with a speed of bps (Eth
The ernet (registered trademark) controller has become a price range that is easily available. In addition, the network infrastructure is beginning to be set up at home, and ISDN (Integrated Servi
ces Digital Network) from 64 Kbps to ADSL
(Asymmetric Digital Subscriber Line) 1Mbp
s, recently 100 in FTTH (Fiber To The Home)
The time has come when a line speed of about Mbps can be obtained at home.

However, in spite of the improvement of such network infrastructure, the mainstream of the software configuration is the information network using the conventional client model. Recently, a peer-to-peer model network sharing technology that does not require a server has been attracting attention, but it has a problem that stable sharing cannot be performed because it is a dynamic model.

The present invention realizes stable network sharing while using the peer-to-peer model.

[0005]

2. Description of the Related Art As a conventional form of data sharing, there has been an information sharing system based on a client / server model (hereinafter referred to as a "class server model"). Windows (registered trademark)
(Windows (registered trademark)) file sharing by network and NFS (Network File System) by UNIX (registered trademark) (Unix) are well known.
However, in general, a server is a high-performance CP that can withstand a heavy load.
U (Central Processing Unit) and I / O (Input-Outp
ut) It was required to have specs and was expensive. Moreover, the management was complicated and required a skilled manager. If for some reason the communication between the client and server was lost (worst crash), the client was powerless with all services stopped.

[0006] In recent years, unlike the conventional Kurasaba model,
There is no need for expensive servers or skilled administrators, and you can freely join and leave the network (power ON / OFF of PC).
A possible dynamic network model (peer-to-peer) is drawing attention. Naps famous for music distribution
ter (Napsta) and Gnutella (Gnutella)
Is an example. However, the peer-to-peer model is based on a dynamic communication model,
After searching for the target data from a specific peer, the communication with the transmission source peer (eg PC) is suddenly interrupted while the download is started (eg router power off, PC
(It shuts itself down), and normal file copy was not performed often.

FIG. 28 is an explanatory view of a conventional example. In FIG. 28, devices such as PCs such as peer A, peer B, and peer C are connected by a network. Peer A has a control unit 1
1, a data transfer unit 12, a data search / determination unit 13, and a communication unit 16 are provided. In this data search / determination unit 13,
The communication unit 16 requests the peers B and C to search for the data to be searched, and when the peer B finds the data, the data is downloaded from the peer B.

In such peer-to-peer (hereinafter, P2P), which has been attracting attention in recent years, unlike the Kurasaba model, communication between peers is not guaranteed. For example, communication with a transmission source peer B (for example, PC) is often suddenly interrupted (router is turned off, or PC itself is shut down) while data (a compression standard MP3 or the like) is being downloaded.

If the download is forcibly terminated on the way, it has been considered that the following method should be used for relief.

Re-execution from the same peer (simple re-execution, re-execution when communication is restored) Re-execution by searching for another peer (in some cases, there is no other peer with data, but there was also a backup) Napter and Gnutella Take the above method. Napster manages only the location of data by the server. The entity (data) is on each peer. Gnutel
la is the location of the data and the entity (data) is each peer. It was perfect P2P.

[0011]

The above-mentioned conventional ones have the following problems.

(1): When the download is forcibly terminated midway, the same peer may not be immediately returned to a ready-to-execute state by re-execution from the same peer (simple re-execution, re-execution at the time of communication restoration). It was For example, the peer may be shut down during the download, or a blue screen (such as an unrecoverable screen) may appear and the personal computer may not start immediately. In this case, even if it waited for a certain time, it could not be executed again, and this method itself could not be executed.

(2): It is possible to find another peer by searching for the other peer and re-execution (there is also the case that there is no other peer having data, but there was a backup), but it is not always necessary. Sometimes the desired data could not be found because it was not guaranteed to exist on other peers.
It is likely to be present if the data is particularly popular or commonly used, but if not, it may only be present on a particular peer. In such cases, this method itself was not feasible.

In view of the above problems, the present invention creates a preparation for surely performing a search. That is, a shared group (service group) for receiving a service is created, and a replica is always created when new data is created in this group. Then, when the download is completed after the data search, another peer is provided with a mechanism for automatically taking over the service to improve the convenience for the user.

[0015]

FIG. 1 is a diagram for explaining the principle of the present invention. FIG. 1 (a) is a diagram for explaining a network and FIG.
(B) is an explanation of the data sharing apparatus. 1-3 in FIG.
Is a device (peers A to C), 10 is a data sharing device, 11a
Is a control means, 12a is a data transfer means, 13a is a data search / determination means, 14a is a replica registration / reference means, 1
Reference numeral 5a is a buffer monitoring / determining means.

The present invention has the following means in order to solve the above conventional problems.

(1): A data sharing device for forming a service group for sharing data between devices connected by a network, and a data transfer means 12a for transferring data with another device, and a data transfer device 12a. A replica registration / reference unit 14a for registering and referring to a replica is provided, and when new data is created by a device in the service group, the replica registration / reference unit 14a creates a replica of the new data and registers it. To do. Therefore, when replicas are created on multiple devices connected to the network, data is made redundant, and after searching for data from a specific device, communication is lost during download from the found device. In addition, you can restart the download from other devices. Further, even if a specific device crashes, it is possible to recover data from its own replica data in another device.

(2): In the data sharing apparatus of (1) above, a buffer for temporarily buffering data transfer and a buffer monitoring / monitoring for monitoring and judging the buffer.
The buffer monitoring / determination means 15a is provided with a determination means 15a, and monitors the buffer amount of the buffer during data transfer, and when the data transfer is delayed, switches to another device and restarts the data transfer. For this reason, when the amount of the transfer buffer is reduced to the amount of communication delay, the next download source is notified and the download can be continued without delay.

(3): In the data sharing apparatus of (1) or (2), the data transfer means 12a first measures the transfer rate at the time of data transfer,
Download from a fast device. Therefore, the download time can be shortened.

(4): (1) or (2) or (3) above
In the data sharing device of, before the data transfer, grasp the number of times data can be copied for creating the replica,
Determine if transfer is possible. Therefore, it is possible to limit the number of times copying is possible and prevent an increase in copying.

(5): In the data sharing apparatus of (1) or (2) above, after the new data is created in the service group, the total size and number of replicas already existing in the device connected to the network. Refer to to determine the replica creation destination so that the replica sizes are balanced in each device. Therefore, by preferentially selecting a replica having a small replica size in each device, it is possible to balance replica sizes in each device and perform efficient data sharing.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, stable network sharing is realized by the following procedure.

A service group is dynamically formed (one-to-one communication on a peer-to-peer basis is performed a plurality of times or multicast (one-to-many) communication).

When new data is created somewhere in the peer, replicas are created in multiple peers (presence of existence in other peers).

Data retrieval is performed within the service group, and is downloaded from the peer with the highest communication speed.

When the download is interrupted, the peer with the next highest communication speed is automatically restarted from the middle of the data.

When data is downloaded, the data flow is monitored through a buffer on the network.

A peer-to-peer data sharing method that realizes the above will be described in detail below.

(1): Description of Overall Block FIG. 2 is an overall block diagram, and FIG. 2 (a) is an illustration of the overall configuration of the P2P network. In FIG. 2A, peers A, P, B, C, D, and E, which are devices such as PCs, are connected by a network.
Here, the peer A is a data transfer request source, and the peer D is a download source of data having a replica. Also, peer E
Is a buffer that is inserted between the download source and the download destination as a buffer at the time of download, and is provided to grasp the transfer status.

FIG. 2 (b) is an explanation of the configuration within each peer. In FIG. 2B, the control unit 11,
A data transfer unit 12, a data search / determination unit 13, a replica registration / reference unit 14, a buffer monitoring / determination unit 15, and a communication unit 16 are provided. The control unit 11 performs overall control. The data transfer unit 12 controls data transfer. The data search / determination unit 13 performs data search and determination of search results. The replica registration / reference unit 14 registers and references a replica that is a replica of the replica. Buffer monitoring / determination unit 15
Is for monitoring and determining a transfer buffer that temporarily buffers data transfer. The communication unit 16 is for performing communication between peers.

When a specific peer requests data transfer,
A search request is issued from a specific peer (here, peer A) to all peers. Among the hit peers, a specific peer (here, peer D) is selected. The selected peer transfers data to the requesting peer via the buffer (here, peer E).

In addition to the conventional data transfer unit 12 and data search / determination unit 13, a replica registration / reference unit 14 and a buffer monitoring / determination unit 15 are newly added. Replica is
It is created by other peers when new data is created.
The (buffer) serves as a P2P buffer that is located between the download source and the download destination as a buffer at the time of downloading, and is provided for grasping the transfer status.

Description of Data Transfer Section The data transfer section 12 is a data transfer means for managing download transfer of data hit in the search.

FIG. 3 is an explanatory diagram of the data transfer section. Figure 3
In the data transfer unit 12, the data transfer control unit 2
1, a management unit 22, a generation management unit 23, and a transfer unit 24 are provided. The data transfer control unit 21 controls data transfer performed via the communication unit 16 with another peer. The management unit 22 manages the generation management unit 23, the transfer unit 24, and the like. The generation management unit 23 manages the number of copies. The transfer unit 24 transfers data.

Description of Data Retrieval / Judgment Unit The data retrieval / judgment unit 13 requests retrieval of the data to be retrieved, and with respect to the response returned from each peer, sees the time and the contents of the replica list, and from which peer It is a data search / determination means for determining whether to download.

FIG. 4 is an explanatory diagram of the data search / determination unit. In FIG. 4, the data search / determination unit 13 is provided with a data search / determination control unit 31, a management unit 32, a search result determination unit 33, and a search unit 34. The data search / judgment control unit 31 controls data search and judgment. The management unit 32 includes a search result determination unit 33 and a search unit 34.
Is to manage. The search result determination unit 33 requests the data to be searched by the search unit 34, checks the time and the contents of the replica list (for example, the replica size to be held, etc.) with respect to the response returned from each peer, and determines which peer It is determined whether to download from. Search unit 34
Is a request for each peer to retrieve data to be retrieved.

Description of Replica Registration / Reference Section The replica registration / reference section 14 is a replica registration / reference means for creating a replica while managing three list files when receiving a replica creation request. These three lists include an overall size of replicas, a replica list that manages the number of replicas, a group list that manages service groups, and a generation management list that manages copy generations of data and original peers.

FIG. 5 is an explanatory diagram of the replica registration / reference section. In FIG. 5, the replica registration / reference unit 14 is provided with a replica registration / reference control unit 41, a replica management unit 42, a replica search unit 43, a replica creation unit 44, and a list 45. The list 45 is provided with a replica list 46, a group list 47, and a generation management list 48.

The replica registration / reference control unit 41 controls the registration / reference of the replica. The replica management unit 42 manages the replica search unit 43, the replica creation unit 44, and the list file 45. The replica search unit 43 searches for a replica. The replica creation unit 44 creates a replica. The list 45 has three lists stored in a storage medium, for example, a hard disk (HDD) 60. The replica list 46 is the entire size of the replica,
It manages the number of replicas. Group list 4
Reference numeral 7 manages a service group. The generation management list 48 manages the data copy generation and the original peer.

Description of Buffer Monitoring / Judgment Unit The buffer monitoring / judgment unit 15 is provided to confirm whether communication is being performed smoothly, and whether the P2P buffer flow is smooth (whether there is any delay). , A buffer monitoring / determining means comprising a P2P monitoring unit for confirming whether or not an underflow has occurred and a P2P buffer determining unit for switching the download source to the next peer according to the result.

FIG. 6 is an explanatory diagram of the buffer monitor / determination unit. In FIG. 6, the buffer monitoring / determination unit 15 includes a buffer monitoring / determination control unit 51 and a P2P buffer management unit 5.
2, a P2P monitoring unit 53, and a P2P buffer determination unit 54 are provided.

The buffer monitoring / judgment control unit 51 uses the P2P
It controls the monitoring and judgment of the buffer. P2P
The buffer management unit 52 manages the P2P monitoring unit 53 and the P2P buffer determination unit 54. The P2P monitoring unit 53 confirms whether or not the flow of the P2P buffer (HDD 60) is smooth. The P2P buffer determination unit 54 switches the download source to the next peer according to the monitoring result of the P2P buffer (HDD 60).

Description of HDD Contents FIG. 7 is an illustration of the contents of the HDD. In FIG. 7, H
The contents of the DD 60 include a list file 61, a replica (data) 62, and a P2P buffer 63, which are three types of data and a list. The list file 61 has three list (replica list 46, group list 47, generation management list 48) areas as shown in detail in FIG.
The replica (data) 62 is an area for holding original data and replica data. The P2P buffer 63 is a transfer buffer area for temporarily buffering data transfer.

(2): Description of change of service group: Description of service group FIG. 8 is an explanatory view of a service group, and FIG. 8A is a description of a logical network. In FIG. 8A, groups of peers A to F are configured. The peers A to F are connected by a logical network (LAN).

FIG. 8B illustrates a physical network. In FIG. 8B, peer B is connected to peer A, peer C, peer D, and peer E, and peer D is peer F.
Connected with. The service group is a logical one, and the physical network is related to the case where the line is broken. When the line between the peer B and the peer D is interrupted in FIG. 8B, the connection between the peer F and the other members than the peer D is also interrupted.

Description of Change (Addition) of Service Group FIG. 9 is an explanatory view of change (addition) of a service group, and FIG. 9A is an explanation when the service group is 2. In FIG. 9A, when the service group is 2 (the IP (Internet Protocol) address of peer B is “203.139.XXX.12”, the IP address of peer C is “203.13”.
9.XXX.10 "). Peer B and Peer C exchange their own IP addresses with each other when creating the service group. It is registered in the group list 47. For example, the peer B group list 47 holds the IP address “203.139.XXX.12” of the peer C.

FIG. 9B shows the case where the peer E joins the group of the peer B and the peer C. In FIG. 9B, the peer E of the IP address “203.139.XXX.13” is
It is the figure which participated in the service group of (a). Pier E
, Will join if they know the IP address of Peer B, and inform Peer B of their intention to join. Get group list from peer B. Peer B communicates that Peer E has newly joined the peers that have joined all other groups. Here, only Peer C. Thus, for example, in the group list 47 of peer B, peer C and peer E
IP addresses of "203.139.XXX.12" and "203.139.XXX.1"
3 ”is retained.

FIG. 10 is a flowchart of the service group participation processing. FIG. 10 is a flowchart showing the situation of FIG. Hereinafter, the process S1 of FIG.
~ S3 will be described.

S1: Peer E connected to the network
Notifies the peer B, which has already joined the service group, of the join request.

S2: Peer B which has received the participation notification from Peer E
Informs the participating peers of the service group (here peer C).

S3: The group list 47 is updated by each peer (peers B, C, E), and this processing ends.

FIG. 11 is a flowchart of the withdrawal process of a service group. It updates in the same way as the participation of FIG. Hereinafter, a description will be given according to the processes S11 to S12 of FIG.

S11: A peer connected to the network (peer wishing to leave) notifies the peers already participating in the service group of the withdrawal. Withdrawal is completed when the notification of withdrawal acceptance is received from the peer. (Or, the notified peer can notify the participating peers of the service group.) S12: Each peer of the service group updates the group list 47 and ends this processing.

Description of List Held by Each Peer FIG. 12 is an explanatory diagram of list (1) held by each peer. In FIG. 12, the IP address “203.139.XXX.10”
Peer B of is Peer A of IP address "203.139.XXX.15"
And a peer C with an IP address "203.139.XXX.12" and a peer D with an IP address "203.139.XXX.16". Each peer has a list 45, and each list 45 has a replica list 46 and a group list 47.
For example, the replica list 46 of the peer B holds the total size of replicas and the number of replicas. The replica list 46 is used as information when creating a replica. The group list 47 includes the addresses (IP addresses “203.139.XXX.15”, “203.139.” Of each peer (A, C, D) used to hold a group for creating a replica.
XXX.12 ”,“ 203.139.XXX.16 ”) are retained.

FIG. 13 is an explanatory diagram of the list (2) held by each peer. In FIG. 13, peer B is connected to peer A, peer C, and peer D. Each peer has list 45
The list 45 holds a generation management list 48 in addition to the replica list 46 and the group list 47 of FIG. For example, the generation management list 48 of peer B is the original peer (A, B, ...) When creating a replica. Data file name (a.mpg, b.mpg
, ...), and the number of copies (1, 2, ...) For managing the copy. If you have your own original, the generation management list will have the same structure.
The original peer becomes your own peer (Peer B). When a replica is created on another peer, the copy count is incremented in response to the replica creation completion notification. Synchronize with the replica creator.

(3): Description of Replica Creation and Search FIG. 14 is an explanatory diagram of replica creation and search.
(A) is an explanation when peer B creates new data. In FIG. 14A, new data is created by peer B, and replicas are created by peer A and peer D. The creation destination is performed after confirming the replica list (for example, confirmation of a peer having a small overall size).

FIG. 14B is an explanation of the search and download. In FIG. 14B, search and download are performed. After downloading the search result, the download destination is
Either the reaction time of PING (ping command) or small data of about 1 Kbyte is communicated to confirm the transfer time and download from the faster peer. In FIG. 14B, the search source peer is E, and the peer B is downloading.

FIG. 15 is a replica creation processing flowchart (1). FIG. 15 shows a flow when data is newly created by some peer. It does not manage the copy generation. When new data is created, it refers to the group list and gets the replica list from each peer. The number N of replicas (arbitrarily one or more) is selected so that the replica sizes are balanced. A request for replica creation is made to the selected peer, and each peer receives it and creates a replica. Then, each peer updates various lists.
If some of the peers are powered off, there is no system problem, just no response from the powered off device. Hereinafter, a description will be given according to the processes S21 to S27 of FIG.

S21: Some peer in the service group creates new data, and the process proceeds to step S22.

S22: The peer that has created the new data refers to the group list 47 and moves to the processing S23.

S23: The peer that has created the new data receives the replica list 46 from each peer in the group list 47, and proceeds to processing S24.

S24: The peer that has created the new data selects N peers having a small overall size from the received replica list 46, and the process proceeds to step S25.

S25: The peer that has created new data requests the selected N peers to create a replica, and the process S2
Go to 6.

S26: The peer, which has received the request for creating the replica, creates the replica, and then proceeds to processing S27.

S27: Each peer updates various lists,
This process ends.

FIG. 16 is a replica creation processing flowchart (2). FIG. 16 shows a flow when data is newly created at some peer. Decide whether to manage copy generations and create replicas. When new data is created, it refers to the group list and gets the replica list from each peer. The number N of replicas (arbitrarily one or more) is selected so that the replica sizes are balanced. Request replica creation for the selected peer. However, if the copy count is other than the specified count, the creation of the replica is rejected. If the number of copies is within the specified number, each peer receives it and creates a replica. Update various lists at each peer. To synchronize the number of times of copying, replicas are sequentially created so that the peers are synchronized. When creating a replica of your own data, be sure to receive an end notification and increment the copy count of the original node. If you exceed the specified number of times, you will not be able to create replicas. For example, even when the power of the peer that created the replica is turned off, the number of copies is written in the original generation management list, so the number of copies will not exceed the permitted number. If some of the peers are powered off, there is no system problem, just no response from the powered off device. Hereinafter, the process S of FIG.
It demonstrates according to 31-S39.

S31: Some peer in the service group newly creates data, and then proceeds to process S32.

S32: The peer that has created the new data refers to the group list 47 and moves to the process S33.

S33: The peer that has created the new data receives the replica list 46 from each peer in the group list 47, and proceeds to processing S34.

S34: The peer that has created the new data selects N peers having a small overall size from the received replica list 46, and the process proceeds to step S35.

S35: The peer that has created the new data requests the selected N peers to create a replica, and the process S3
Go to 6.

S36: The replica creation requesting side (peer that has created new data) checks the number of times the generation management list has been copied, and proceeds to processing S37.

S37: The replica creation requesting side determines whether or not the copy count is smaller than the permission count. If the number of copies is smaller than the number of times permitted in this determination, the process proceeds to step S38. If not, the replica creation is prohibited and the process ends.

S38: The peer, which has received the request to create the replica, creates the replica and moves to the processing S39.

S39: Each peer updates various lists,
This process ends.

FIG. 17 is a flowchart for creating both new data and a replica by another peer. FIG. 17 shows a case where newly created data is held by another peer instead of its own peer. For example, if the storage location of peer A is full (possible even if there is still room),
You can do it even if you don't have your own disc at all. Further, even if there is his own HDD, if his HDD is out of space and the capacity of other peers in the service group is full, data can be created. Hereinafter, a description will be given according to the processes S41 to S48 of FIG.

S41: Peer A creates new data,
The process moves to S42.

S42: The peer A that has created the new data
When the own storage area is full, the process proceeds to step S43 (this processing block can be omitted).

S43: The peer A that has created the new data
The group list 47 is referred to, and the process proceeds to S44.

S44: The peer A that has created the new data
The replica list 46 is received from each peer, and the process proceeds to step S45.

S45: The peer A that has created the new data
From the received replica list 46, N peers having a small overall size are selected, and the process proceeds to step S46.

S46: The peer A that has created the new data
Ask the selected peer to create the original + replica,
The process moves to S47.

S47: The peer requested to create a replica creates a replica, and the process proceeds to step S48 (any one of the requested N peers holds the original).

S48: Each peer updates various lists,
This process ends.

(4): Description when a certain peer crashes FIG. 18 is an explanatory diagram when a certain peer crashes. In FIG. 18, a case where the peer C indicated by X has crashed is shown. If C crashes, it will recover the data from the other peers (A, B, D).

FIG. 19 is a flowchart when a certain peer crashes. FIG. 19 is a flowchart for recovering data from another peer when one peer crashes or data becomes unreadable. For example, if peer C crashes, replaces the HDD, and restarts, it tries to join the service group again. If you join, whether the IP address is the same or GUID
Recognize that the same peer has joined with (Global Unit ID) (in this case, the group list 47 also needs to hold the GUID). Here, you can choose whether to newly join from the beginning or recover the data. If it is new, it is usually the same as new participation. If you choose to recover, collect data from each peer to recover. Data is restored by sequentially copying back the data from the peer having the data of peer C from the generation management list of each peer. In addition, GUID
Is a unique ID, for example, there is a MAC address of the Ether card (a hardware address of the Ethernet board is one address in the world), and a 128-bit random value may be automatically generated. Hereinafter, a description will be given according to the processes S51 to S58 of FIG.

S51: When the peer C crashes, the process proceeds to S52.

S52: The peer C is restarted (no data is stored in the HDD), and the process proceeds to S53.

S53: The restarting peer C notifies the service group (peer of the existing participant) of the participation, and the process proceeds to step S54.

S54: The peer notified of the participation in the service group refers to the GUID and moves to processing S55.

S55: The peer which has been notified to join the service group is the peer C who has restarted and wishes to join.
Is recognized as an existing group member, and the peer C is made to judge whether or not to restore the data. In this determination, if data is to be restored as an existing group member, the process proceeds to step S56, and if not restored, this process ends.

S56: The peer (or peer C) notified of participation in the service group notifies the peer of the service group and asks if it has the file of peer C, and proceeds to processing S57.

S57: The peer (or peer C) notified to join the service group copies back to the peer C in order from each peer having the file of the peer C, and the process S
Move to 58.

S58: The peer (or peer C) notified of participation in the service group judges whether or not all the copies have been completed. In this determination, if all the copies have been completed, this process ends, and if the copies have not completed, the process returns to step S57.

(5): Description of data retrieval method When retrieving the target data, each peer is checked to see if the data exists. If there is data, the answer will be returned. If not, there is no answer. To find a peer with a high communication speed, look at the PING response or download dummy data with a small data size and measure the communication speed. It is more efficient to download data from a peer with a fast transfer rate. Two methods shown in FIGS. 21 and 22 can be used to determine whether or not the download is delayed. FIG. 20 is a data search processing flowchart. Hereinafter, a description will be given according to the processes S61 to S70 of FIG.

S61: The peer performing the data search refers to the group list 47 and moves to the process S62.

S62: The peer performing the data search notifies the search condition (for example, the data file name a.mpg) and performs the search, and the process proceeds to step S63.

S63: When the peer that has performed the data search receives a search hit from N peers, the process proceeds to step S64.
If there is no hit, this process ends.

S64: The peer performing the data search receives about 1 Kbyte of data from the hit N peers, measures the communication speed (or sees the PING response speed time), and proceeds to processing S65.

S65: The peer that has performed the data search creates a ranking list of download destinations (in order of speed), and proceeds to processing S66.

S66: The peer that has performed the data search keeps the communication paths open for the top N peers, and proceeds to step S67.

S67: The peer that has performed the data search starts downloading the data from the peer having a high transfer rate, and moves to the processing S68.

S68: Downloading peer (or 2P)
Peer with 2 buffers, or peer with next ranking)
Determines whether the download is normal. With this judgment,
If the download is normal, this process ends. If it is not normal (stops midway (timeout)), process S69.
Move on to.

S69: Downloading peer (or 2P)
Peer with 2 buffers, or peer with next ranking)
Selects the next candidate (the peer with the next highest transfer speed) and moves to process S70.

S70: Downloading peer (or 2P)
Peer with 2 buffers, or peer with next ranking)
Determines whether there is no next candidate selected. In this determination, if there is no next candidate, this process ends, and if there is, the process returns to process S67.

Description of Case where Time-Out is Determined on Download Side The method (1) for judging whether the download is normally completed is a method for making a time-out judgment (decision that the download has stopped halfway) on the download side. When the download is stopped halfway, the time when communication is interrupted is measured at a certain specific time, and it is assumed that the time has passed (timeout). The download requester recognizes the time-out and downloads again from the next peer. FIG. 21 is a flow chart of the method (1) for determining the normal end of download.
Hereinafter, a description will be given according to the processes S71 to S75 of FIG.

S71: The download-side peer starts the download, and proceeds to processing S72.

S72: The downloading peer determines whether the data transfer is continuing. In this determination, if the data transfer is continued, the process returns to step S71, and if not, the process proceeds to step S73.

S73: The downloading peer determines whether the data transfer is completed. In this determination, if the data transfer is completed, this processing is ended, and if not completed, the processing S
Move to 74.

S74: The download-side peer determines whether or not a timeout has occurred. In this determination, if the time is out, the process proceeds to step S75, and if not, the process returns to step S71.

S75: The download-side peer makes a transfer start request to the next candidate peer and ends this processing.

Description of the case where the normal termination of download is determined using the P2P buffer: (a) of the method (2) for determining the normal termination of download is P
A peer with a 2P buffer monitors and notifies the next peer, (b)
Is for the next candidate to monitor and switch for themselves. P
The 2P buffer acts as a buffer for communication. P2
The P-buffer is somewhere on each peer. Monitor the buffer for underflow (the supply of data is delayed) and switch to the next transfer source when an underflow is about to occur. The P2P buffer will be somewhere on the peer. P2P
The buffer may be monitored by the peer with the P2P buffer or by the next download candidate peer.

FIG. 22 is a flow chart of the method (2) for judging the normal end of download, and FIG.
It is an explanation when a peer having a buffer monitors. Hereinafter, a description will be given according to the processes S81 to S84 of FIG.

S81: The peer having the P2P buffer regularly monitors the P2P buffer amount and moves to the processing S82.

S82: The peer having the P2P buffer judges whether the data transfer is completed. In this determination, if the data transfer is completed, this process is terminated, and if not completed, the process proceeds to step S83.

S83: The peer having the P2P buffer judges whether it is an underflow. In this determination, if underflow occurs, the process proceeds to step S84. If not underflow, the process returns to step S81.

S84: The peer having the P2P buffer switches the communication to the next candidate peer and ends this processing.

FIG. 22B shows the case where the next candidate peer monitors and switches itself. Hereinafter, a description will be given according to the processing S91 to S94 of FIG.

S91: The next candidate peer is periodically P2P.
The buffer amount is monitored, and the process proceeds to step S92.

S92: The next candidate peer determines whether or not the data transfer is completed. In this determination, if the data transfer is completed, this process is ended, and if not completed, the process proceeds to step S93.

S93: The next candidate peer determines whether it is an underflow. In this determination, if underflow occurs, the process proceeds to step S94. If not underflow, the process returns to step S91.

S94: The next candidate peer switches communication to itself and ends this processing.

As described above, since the next candidate peer monitors, the data can be sent immediately when the underflow is judged.

(6): Description of Download FIG. 23 is an explanatory diagram of download from peer A to peer D. In FIG. 23, peers A to F forming a service group are connected by a network. P2P
The buffer is actually what is placed on each peer. FIG. 23
Shows a configuration including a P2P buffer (download from A to D). It shows that the download from peer A to peer D is going through the P2P buffer of peer B. The P2P buffer exists somewhere in one peer, and actually does not look like the one shown in the figure, but goes through some peer.

FIG. 24 is an explanatory diagram of a download source switch using a P2P buffer. In FIG. 24, P
The 2P buffer 63 is located at peer B and indicates a download from peer A to peer D. Further, the buffer amount (hatched portion) is monitored by the peer B or the next candidate peer C.

That is, corresponding to FIG. 22, the peer A is the data supply source (download data supply source) and the peer D is the side requesting the download. That is, the source of data to the P2P buffer 63 is the peer A, and P2
The data consuming peer of the P buffer 63 is peer D. P2
The P buffer 63 shows an example in the peer B. The next candidate for download is peer C. The shaded portion is the amount of data, and if the shaded portion disappears before the transfer ends, it means that the data has underflowed. Switch to the next candidate peer C before underflow (before the buffer amount is less than a certain amount). Underflow is monitored by the next candidate peer C (FIG. 22A).
Flow) or peer B with a P2P buffer (see FIG. 22).
(B) flow).

(7): Description of Data Communication FIG. 25 is an explanatory diagram of a communication interface. In FIG. 25, the communication between the client server and the UNIX
Shows an example of the socket interface used in. In the socket interface, communication is roughly divided into three phases. Connection connection phase,
The data transfer phase and the connection release phase. Connection In the connection phase, "socket ()" that creates an endpoint and returns a socket descriptor,
Socket name "bind", connection completed "liste"
n () ", server waits for connection" accept () ", waits for connection" c "
onnect () "is available. The data transfer phase includes read "read ()" and write "write ()". In the connection release phase, the close socket "closesocke
t () ”

In the present embodiment, the connection connection phase is terminated and the data transfer phase can be immediately entered so that communication with another peer can be started immediately when communication is interrupted during downloading. deep.

FIG. 26 is an explanatory diagram of communication in the case of a firewall. In FIG. 26, peers A to D and peer F are connected via the Internet, and peers E and D having local addresses are connected via the NAT function. In this example, the data is downloaded from peer D to peer E via a NAT function such as a router. Thus, if either the download source or the download destination is the firewall source, communication is possible. Not in both cases. It uses the NAT (The IP Network Address Translator) function recently used in routers and the like. IP that cannot be used on the Internet
Even a personal computer (PC) that has only an address (local address) can connect to the Internet.

That is, the NAT function translates a global address that can be connected to the Internet (outside world network) and a local address that can be used only inside the firewall. Even if the plural terminal is connected under the router having the NAT function, it can be connected with the global address for one unit.

(8): Description of Digital Data Sharing Device FIG. 27 is an explanatory diagram of a digital data sharing device. Figure 2
In 7, the digital data sharing device is a network sharing device that shares data between devices connected by a network. The digital data sharing device has a CPU
A block 71, a network block 72, a memory block 73, an interface block 74, and a large capacity storage block 75 are provided.

The CPU block 71 controls the whole. The network block 72 is for communicating with other devices. The memory block 73 is for storing a control program. The interface block 74 receives a request from a user. The large-capacity storage block 75 holds a replica and a communication buffer (HDD, DVD, MO, etc.).

In the digital data sharing apparatus, when new data is created, a replica creation request or a request is accepted on a plurality of other devices (digital data sharing apparatus) connected to the network.

(9): Explanation of Program Installation Control means 11a, control section 11, data transfer means 12a,
Data transfer unit 12, data search / determination unit 13a, data search / determination unit 13, replica registration / reference unit 14a,
Replica registration / reference unit 14, buffer monitoring / determination means 1
5a, the buffer monitoring / determination unit 15, the communication unit 16 and the like can be configured by a program, are executed by the main control unit (CPU), and are stored in the main memory. This program is processed by a general computer. This computer is configured with hardware such as a main control unit, a main memory (memory block), a file device, a display device, and an input device that is an input means such as a keyboard.

The program of the present invention is installed in this computer. This installation is performed on a portable recording medium such as a floppy disk or magneto-optical disk.
These programs are stored and installed in a file device provided in the computer via a drive device for accessing a recording medium included in the computer or via a network such as a LAN. It Then, the program steps required for processing are read from the file device to the main memory and executed by the main control unit. By installing this program in a computer, it is possible to easily provide a data sharing device that can restart the download from another device when communication becomes impossible during the download.

As described above, the present embodiment has the following effects.

A service group is dynamically formed (one-to-one communication on a peer-to-peer basis is performed a plurality of times or multicast (one-to-many) communication).

As a result, by forming a group that shares data, it becomes possible to share the data storage mediums held by other parties. You can also have security to deny access from peers outside the group. It can identify the person to be notified and does not increase unnecessary traffic on the network.

When new data is created somewhere on the peer, replicas are created on multiple peers (presence of existence on other peers).

As a result, it is possible to make data redundant and to ensure that a plurality of peers have the same data. Even if one peer cannot communicate, data can be downloaded if another peer can communicate. If a particular peer crashes,
From your replica data on other peers to your HDD
Can be restored.

The data search is performed within the service group and is downloaded from the peer with the highest communication speed.

As a result, since it is guaranteed that the target data exists in a plurality of peers, it is possible to select from which of the plurality of peers the data is downloaded. There is a possibility that you can select the peer with the highest communication speed and save the data download time. Since replicas are guaranteed to exist in multiple peers, parallel download is possible by specifying multiple peers as the download source.

When the download is interrupted, the peer with the next highest communication speed is automatically restarted from the middle of the data.

Since this guarantees that a plurality of peers have the same data, if the communication of one peer is interrupted, it can be changed to another peer immediately.
When selecting the first peer, if the communication speed is measured by all peers, if the communication of the fastest peer is cut off,
You can quickly find the next fastest peer. If you remember how much data you downloaded with the data size,
Even if the peer is transferred to another peer, it can be restarted from the middle, and the total download time is not increased even though the download source peer is changed. Although a system that downloads from other peers with a normal backup configuration is also conceivable, in the present invention, a buffer (P2P buffer) is provided in the middle of the communication path, communication is passed through the buffer, and the buffer amount is monitored. When the buffer becomes small, it can be transferred to another peer seamlessly.

When data is downloaded, the data flow is monitored through a buffer on the network once.

Thus, by realizing the download through the network buffer, it becomes possible to detect the delay of the download quickly. Even if the download source peer becomes unable to continue communication for some reason, the download source can be switched without being known to the download receiving side (without a time lag). In other words, seamless cooperation becomes possible.

[Additional remarks below] (Additional remark 1) A data sharing apparatus for forming a service group for sharing data between devices connected by a network, and data for performing data transfer with other devices A transfer unit and a replica registration / reference unit for registering and referring to a replica of data are provided, and when new data is created by a device in the service group, the replica registration / reference unit creates a replica of the new data. A data sharing device characterized by creating and registering.

(Supplementary Note 2) The data sharing apparatus according to supplementary note 1, wherein the data transfer means switches to another device and restarts the download when communication becomes impossible during the download.

(Supplementary Note 3) A buffer for temporarily buffering data transfer and a buffer monitoring / determining means for monitoring and determining the buffer are provided, and the buffer monitoring / determining means is the buffer amount of the buffer during data transfer. The data sharing apparatus as set forth in appendix 1, wherein the data sharing is monitored and when the data transfer is delayed, the device is switched to another device to restart the data transfer.

(Supplementary Note 4) The buffer monitoring / judging means for monitoring the buffer amount is provided in the next candidate device or device having the buffer for switching and restarting the data transfer when the data transfer is delayed. The data sharing apparatus as described in Appendix 3, which is characterized.

(Supplementary Note 5) The registration location of the replica and the location of the buffer are placed somewhere in the devices in the service group connected to the network based on the list held by each device. The data sharing apparatus according to Appendix 3.

(Supplementary Note 6) When a notification of joining or leaving the service group is received from another device,
5. The data sharing apparatus according to any one of appendices 1 to 4, characterized in that all the other participants are notified based on the group list and the group lists are mutually updated.

(Supplementary Note 7) Any one of Supplementary Notes 1 to 5 characterized in that the data transfer means first measures the transfer rate at the time of data transfer, and downloads from a device having a high transfer rate. The data sharing device according to claim 1.

(Additional remark 8) Before data transfer, additional remarks 1 to 5 are characterized in that the number of times data can be copied for replica data is grasped and it is judged whether the data can be transferred.
The data sharing device according to any one of 1.

(Supplementary Note 9) After the new data is created in the service group, the total size and the number of replicas already existing in the devices connected to the network are referred to, and the sizes of the replicas in the respective devices are balanced. 6. The data sharing apparatus according to any one of appendices 1 to 5, wherein the replica creation destination is determined so as to be arranged as described above.

(Supplementary Note 10) Data sharing means for forming a service group for sharing data between devices connected via a network, data transfer means for transferring data with other devices, and A computer-readable recording medium having a program or a program for causing a computer to function as replica registration / reference means for creating and registering a replica of new data when a device creates new data.

[0157]

As described above, the present invention has the following effects.

(1): When new data is created by the device in the service group, the replica registration / reference means
In order to create and register a replica of the new data, create replicas on multiple devices connected to the network, add redundancy to the data, retrieve data from a specific device, and When communication is lost during download, the download can be restarted from another device, and even if a specific device crashes, the data can be recovered from its own replica data in the other device.

(2): The buffer monitoring / judging means monitors the buffer amount of the buffer during data transfer, and if the data transfer is delayed, another device is switched to restart the data transfer. You can notify that effect and continue downloading without delay.

(3): The data transfer means 12a first measures the transfer speed at the time of data transfer,
Since the download is performed from a device having a high speed, the download time can be shortened.

(4): Before data transfer, the number of times data can be copied to create a replica is grasped to determine whether the data can be transferred, so that the number of times copying is possible is limited to prevent an increase in copying. can do.

(5): After new data is created in the service group, reference is made to the total size and number of replicas already existing in the devices connected to the network so that the sizes of the replicas in each device are balanced. Since the replica creation destination is determined so as to be placed in such a manner, it is possible to give priority to and select a replica having a small size of replicas in the devices, balance the replica sizes among the devices, and perform efficient data sharing.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is an overall block diagram in the embodiment.

FIG. 3 is an explanatory diagram of a data transfer unit according to the embodiment.

FIG. 4 is an explanatory diagram of a data search / determination unit in the embodiment.

FIG. 5 is an explanatory diagram of a replica registration / reference unit according to the embodiment.

FIG. 6 is an explanatory diagram of a buffer monitoring / determining unit according to the embodiment.

FIG. 7 is an explanatory diagram of contents of the HDD according to the embodiment.

FIG. 8 is an explanatory diagram of service groups according to the embodiment.

FIG. 9 is an explanatory diagram of changing (adding) a service group according to the embodiment.

FIG. 10 is a flowchart of service group participation processing according to the embodiment.

FIG. 11 is a flowchart of a withdrawal process of a service group according to the embodiment.

FIG. 12 is an explanatory diagram of a list (1) held by each peer in the embodiment.

FIG. 13 is an explanatory diagram of a list (2) held by each peer in the embodiment.

FIG. 14 is an explanatory diagram of replica creation and search according to the embodiment.

FIG. 15 is a replica creation processing flowchart (1) according to the embodiment.

FIG. 16 is a replica creation processing flowchart (2) in the embodiment.

FIG. 17 is a flowchart for creating both new data and a replica by another peer according to the embodiment.

FIG. 18 is an explanatory diagram when a certain peer crashes in the embodiment.

FIG. 19 is a flowchart when a certain peer crashes in the embodiment.

FIG. 20 is a flowchart of a data search process according to the embodiment.

FIG. 21 is a flowchart of a method (1) of determining whether download has ended normally in the embodiment.

FIG. 22 is a flowchart of a method (2) of determining whether download has ended normally in the embodiment.

FIG. 23 is an explanatory diagram of downloading from peer A to peer D in the embodiment.

FIG. 24 is an explanatory diagram of a download source switch using the P2P buffer according to the embodiment.

FIG. 25 is an explanatory diagram of a communication interface according to the embodiment.

FIG. 26 is an explanatory diagram of communication in the case of a firewall according to the embodiment.

FIG. 27 is an explanatory diagram of a digital data sharing apparatus according to an embodiment.

FIG. 28 is an explanatory diagram of a conventional example.

[Explanation of symbols]

1 to 3 devices (peers A to C) 10 Data sharing device 11a Control means 12a Data transfer means 13a Data search / determination means 14a Replica registration / reference means 15a Buffer monitoring / determining means

Claims (5)

[Claims] 1. A data sharing device for forming a service group for sharing data between devices connected by a network, wherein the data transfer means performs data transfer with another device, and registration of a data replica. And a replica registration / reference unit for referencing, wherein when new data is created by a device in the service group, the replica registration / reference unit creates and registers a replica of the new data. Data sharing device. 2. A buffer for temporarily buffering data transfer, and buffer monitoring / determining means for monitoring and determining the buffer, wherein the buffer monitoring / determining means monitors the buffer amount of the buffer during data transfer. The data sharing apparatus according to claim 1, wherein when the data transfer is delayed, the device is switched to another device to restart the data transfer. 3. The data transfer means, when transferring data,
3. The data sharing apparatus according to claim 1, wherein the transfer speed is first measured and then downloaded from a device having a high speed. 4. The data according to any one of claims 1 to 3, wherein before the data transfer, the number of possible data copies of the data for which a replica is created is grasped to judge whether or not the data can be transferred. Shared device. 5. After the new data is created in the service group, the total size and the number of replicas already existing in the devices connected to the network are referred to so that the sizes of the replicas in each device are balanced. 3. The data sharing apparatus according to claim 1, wherein the replica creation destination is determined so as to be arranged.