File transfer server

The present invention relates to a technique for accessing files existing on different networks.

Using call control protocols such as SIP (Session Initiation Protocol) and DDNS (Dynamic Domain Name System), communication terminals existing in different LANs can communicate directly over the WAN. It is a so-called VPN (Virtual Private Network) technology that allows you to use different LANs in remote locations as if they were directly connected networks.

By using such a technology, for example, it is possible to connect a LAN between the head office and a branch office and perform communication over the Internet between terminals connected to each LAN.

Patent Document 1 enables communication terminals connected to different LANs to communicate with each other over the Internet. In this technology, different communication terminals connected to different LANs log in to a relay server connected to the Internet via a gateway, and establish a communication path with each relay server. There is. Then, using this communication path, it is possible to communicate between communication terminals over the Internet. The technology of Patent Document 1 is a technology that enables communication between LANs by using a relay server existing on a WAN.

In addition, there is a technology for sharing files that exist on different LANs. For example, it is possible to share files between LANs built on different floors in the company. Employees on one floor can access files that exist on the LAN on another floor by referring to the network shared folder.

<patcit num="1"><text>Japanese Unexamined Patent Publication No. 2002-217938</text></patcit>

<p> As mentioned above, it was possible to share files between different LANs, but there were various obstacles to safely sharing files between different LANs across the Internet and the like. In other words, making it possible to refer to the shared information of a file as it is via the Internet or the like has many security problems, so another mechanism was required.</p><p> Further, in the current file sharing system, there is a problem that the referenceability is poor when there are many folders and files in the shared state. That is, when a large number of folders and files are displayed in the shared list, there is a problem that the work of finding the target folder or file from them becomes complicated.</p><p> Therefore, in view of the above problems, the present invention constructs a mechanism for safely and practically sharing files across a wide area network such as the Internet, and refers to and accesses only the folders and files required for each user. The challenge is to provide the technology that makes it possible.</p>

<p> In order to solve the above problem, the invention according to claim 1 is a file transfer server that is arranged in a local area network and can communicate with an external server arranged in the wide area network, and obtains file information in the local area network. A list creation means for collecting and creating a file list, a means for registering the account information of the own device in the external server, and other means specified by a communication terminal in the local area network and registered in the external server. From the file transfer server via the external server<u style="single">Created by the other file transfer server</u>How to get the file list and how to get it<u style="single">Created by the other file transfer server</u>A means to store the file list in association with the requesting communication terminal, and from a communication terminal in the local area network<u style="single">Created by the other file transfer server</u>When a file list reference request is received, it is associated with the requesting communication terminal.<u style="single">Created by the other file transfer server</u>It is characterized by providing a means for presenting a file list.</p><p> The invention according to claim 2 is designated when the file transfer server according to claim 1 receives a request from a communication terminal in the local area network to acquire a file included in the file list associated with the communication terminal. It is characterized in that a communication session for relay is established with the file transfer server in which the registered file is registered, and a request for acquiring the specified file is sent to the file transfer server.</p><p> The invention according to claim 3 is a file transfer server arranged in a local area network and capable of communicating with an external server arranged in a wide area network, and collects file information in the local area network to obtain a file list. A means for creating a list to be created, a means for registering the account information of the own device in the external server, and another file transfer server registered in the external server when a file search instruction is received from a communication terminal in the local area network. From the file transfer server specified by the requesting communication terminal or preset, via the external server.<u style="single">Created by the other file transfer server</u>How to get the file list and how to get it<u style="single">Created by the other file transfer server</u>If the file list contains files to search for<u style="single">Created by the other file transfer server</u>It is characterized by providing a means for presenting a file list to a communication terminal of a requesting source.</p><p> The invention according to claim 4 is a file transfer server in which a specified file is registered when a request for acquisition of a file searched from a communication terminal in a local area network is received in the file transfer server according to claim 3. It is characterized by establishing a communication session for relaying with and sending a request for acquiring a specified file to the file transfer server.</p>

<p> The file transfer server of the present invention requests a file list from a file transfer server designated by a communication terminal, and manages the received file list in association with the requesting communication terminal. As a result, the communication terminal can share a file existing in another LAN or the like beyond the Internet or the like. Since the file list is managed by the received file transfer server, it is safe for security. Further, since the file list is managed in association with the communication terminal, it is possible to present a dedicated file list to each communication terminal. Each communication terminal can use a dedicated shared list that is frequently referred to.</p><p> Further, when the file transfer server of the present invention receives a file search request from the communication terminal, the file transfer server acquires a file list from another file transfer server and presents the search result to the communication terminal. As a result, the communication terminal can search and use a file existing in another LAN or the like beyond the Internet or the like.</p>

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall view of the communication system according to the present embodiment. This communication system consists of the Internet 3 and three LANs 1, 2, and 5 connected to the Internet 3. LAN1,2,5 are networks constructed in physically separated locations. For example, LAN1 is a local network built in the head office building, LAN2,5 is a local network built in a branch office building, and these three LANs1,2,5 are connected to the global network Internet3, respectively. Has been done.

As shown in the figure, the communication terminal 11 and the file server 12 are connected to LAN1. A private IP address is assigned to each of the communication terminal 11 and the file server 12. In this way, in general, terminals connected to a LAN are given a private IP address that is uniquely managed only within the LAN. In addition, the file transfer server 13 is connected to LAN1. The file transfer server 13 is connected to the Internet 1 as well as to the Internet 3. The file transfer server 13 is assigned a private IP address for the LAN interface and a global IP address for the WAN interface.

A communication terminal 21 to which a private IP address is assigned and a file server 22 are connected to LAN2. In addition, the file transfer server 23 is connected to LAN2. The file transfer server 23 is connected to LAN 2 and also to Internet 3, and is given a private IP address for the LAN interface and a global IP address for the WAN interface. Similarly, the communication terminal 51, the file server 52, and the file transfer server 53 are connected to LAN5.

Furthermore, the SIP server 4 is connected to the Internet 3. SIP server 4 has a function as a proxy server that relays SIP methods and responses when file transfer servers 13, 23, 53 communicate using SIP (Session Initiation Protocol), and file transfer servers 13, 23. It has a function as a SIP registrar server that registers 53 accounts.

FIG. 2 is a functional block diagram of the file transfer servers 13, 23, 53. Since the file transfer servers 13, 23, and 53 have the same functions, they will be described using the same drawings. The file transfer servers 13, 23, 53 include a LAN interface 101, a WAN interface 102, a communication control unit 103, a file list database 104, and a file list management unit 105.

The LAN interface 101 is an interface that communicates with a terminal connected to the LAN by using a private IP address. That is, the file transfer server 13 uses the LAN interface 101 to communicate with the communication terminals 11 and the file server 12, and the file transfer servers 23 and 53 use the LAN interface 101 to communicate with the communication terminals 21, 51 and the like. Communicates with file servers 22,52.

The WAN interface 102 is an interface that uses a global IP address to communicate with a SIP server 4 connected to the Internet 3 which is a global network, other communication servers connected to the Internet 3, and a communication terminal. In the present embodiment, the file transfer server is configured to have a WAN interface, but the router may connect to the WAN and the file transfer server may be installed under the router.

The communication control unit 103 is a processing unit that controls various communications performed via the LAN interface 101 and the WAN interface 102. The communication control unit 103 controls various communication processes according to protocols such as TCP / IP, UDP, and SIP.

One function of the communication control unit 103 includes a function of sending a registration request (REGISTER) for registering an account of the file transfer server itself to the SIP server 4.

The communication control unit 103 also has a function of establishing a media session and communicating with the file transfer servers 13, 23, 53 on the other side. That is, the file transfer server can establish a media session with another file transfer server by sending the SIP INVITE method. The communication control unit 103 of the file transfer servers 13, 23, 53 makes it possible to perform data communication between the file transfer servers by using this established media session.

The file management unit 105 is a functional unit that manages a list of files shared in the LAN. The file management unit 105 accesses the file server and creates a list of files shared in the LAN. In addition, a specific shared folder of the file server can be registered in the file management unit 105. As a result, the file management unit 105 can periodically monitor the registered shared folder and automatically update the file list when a file in the folder is added or deleted. For example, the file management unit 105 included in the file transfer server 13 periodically accesses the file server 12, creates a list of shared files stored in the file server 12, and stores the list in the file list database 104.

In addition, the file management unit 105 has a function of acquiring a file list from another file transfer server in response to a designation from a communication terminal connected to the LAN. The file transfer servers 13, 23, 53 use the SIP SUBSCRIBE method to acquire the file list. That is, when the SUBSCRIBE method is sent from one file transfer server to the other file transfer server, the file transfer server that received the SUBSCRIBE method is the file list stored in the file list database 104 of the own device. It sends a list of files shared on the LAN to which the own device is connected to the requester. Then, when the requesting file transfer server receives the file list, the requesting file transfer server stores the file list in the file list database 104 in association with the source file transfer server account and the requesting communication terminal account.

For example, suppose that the communication terminal 11 requests to acquire a file list in which the file transfer server 23 is specified. In this case, when the SUBSCRIBE method is transmitted from the file transfer server 13 to the file transfer server 23, the file transfer server 23 transfers the list of files shared by LAN2 to the file transfer server 13. Then, the file transfer server 13 stores the received file list in the file list database 104 in association with the account of the file transfer server 23 and the account of the communication terminal 11.

On the contrary, when the file transfer server receives a request to send the file list from another file transfer server by the SUBSCRIBE method, and then when the file list is updated, the file list is continuously sent to the request source. It sends a change notification and a list of updated files. In other words, when the file list changes, the requester is set to always send the latest file list.

FIG. 3 is a functional block diagram of SIP server 4. As shown in the figure, the SIP server 4 includes a WAN interface 41, a communication control unit 42, and an account information database 43.

The WAN interface 41 is an interface for communicating with a server and a terminal connected to the Internet 3 by using a global IP address. The SIP server 4 can communicate with the file transfer servers 13, 23, 53 by using the WAN interface 41.

The communication control unit 42 is a processing unit that controls various communications performed via the WAN interface 41. The communication control unit 42 controls communication processing according to protocols such as TCP / IP, UDP, and SIP.

One function of the communication control unit 42 is to receive an account registration request (REGISTER) from a file transfer server connected to the Internet 3 and register the account information of the file transfer server in the account information database 43. is there. For example, the SIP server 4 receives an account registration request (REGISTER) from the file transfer server 13 and registers the account information of the file transfer server 13 in the account information database 43.

The communication control unit 42 also has a function of relaying communication data such as various SIP methods and responses transmitted from the file transfer servers 13, 23, 53 to the other file transfer server.

The flow of communication processing in the communication system configured as described above will be described with reference to the processing sequence diagrams of FIGS. 4 to 6. Note that FIG. 4 shows a sequence from step S1 to step S7, followed by steps S8 to S9 in FIG. 5, and step S10 in FIG.

First, the file transfer server 13 sends an account registration request (REGISTER) to the SIP server 4 (step S1). As shown in the figure, here, the file transfer server 13 makes a registration request for its own account (SIP: relay-server1@sip.srv). The SIP server 4 returns an OK response to the file transfer server 13, associates the account of the file transfer server 13 with the global IP address of the file transfer server 13, and registers it in the account information database 43. When performing password authentication, the account of the file transfer server and the password are registered in the account information database 43 in advance in association with each other. In this case, the user sends the password at the time of the registration request. Then, when the password authentication is successful, the account is registered in association with the IP address.

Subsequently, the file transfer server 23 sends an account registration request (REGISTER) to the SIP server 4 (step S2). As shown in the figure, here, the file transfer server 23 makes a registration request for its own account (SIP: relay-server2@sip.srv). The SIP server 4 returns an OK response to the file transfer server 23, associates the account of the file transfer server 23 with the global IP address of the file transfer server 23, and registers it in the account information database 43. Similarly, password authentication may be performed.

Next, the file transfer server 23 accesses the file server 22 and performs a file search (step S3). Here, it is assumed that the shared folder (folder002) of the file server 22 is registered in the file transfer server 23 as the target of the file search. Therefore, the file transfer server 23 performs a file search for this folder (folder002). The file transfer server 23 receives the file list as the file search result from the file server 22, and stores the file list in the file list database 104 provided in the own device.

Subsequently, the file transfer server 53 sends an account registration request (REGISTER) to the SIP server 4 (step S4). As a result, the account (SIP: relay-server3@sip.srv) of the file transfer server 53 is registered.

Next, the file transfer server 53 accesses the shared folder (folder003) of the file server 52 and performs a file search (step S5). That is, the file transfer server 53 registers the shared folder (folder003) of the file server 52 as a search target. The file transfer server 53 receives the file list as the file search result and stores it in the file list database 104 provided in the own device. Although not shown in the figure, the file transfer server 13 also creates a list of shared files in LAN1 in the same manner.

Next, the communication terminal 11 makes a request for acquiring the shared folder list (step S6). Then, the file transfer server requesting the list is specified in this acquisition request. In this example, the file transfer server 23 account (SIP: relay-server2@sip.srv) is specified.

Accordingly, the file transfer server 13 sends a file list transfer request (SUBSCRIBE) to the file transfer server 23 (step S6.1). On the other hand, the file transfer server 23 returns the file list by the NOTIFY method. That is, it returns a list of files shared on LAN2. Figure 4 shows the returned file list FL1. In the file list FL1, three files (file004 to file006.pdf) stored in the shared folder (folder002) of the file server 22 are recorded.

You can also set access rights to shared files. In this case, the account (client-pc1) of the requesting communication terminal 11 is specified in the transfer request in step S6.1. The file transfer server 23 returns only the file list to which the communication terminal 11 has the right to access. Further, the communication terminal 11 may specify a folder or a file to be included in the file list. In this case, the file transfer server 13 or the file transfer server 23 returns only the list that matches the specified folder or file to the communication terminal 11.

The file transfer server 13 associates the received list with the account of the file transfer server 23 (relay-server2.@sip.srv) and the account of the requesting communication terminal 11 (client-pc1), and the file list database 104 Store in. The contents of the stored file list FL2 are shown in the figure. That is, this file list is a file list dedicated to the communication terminal 11.

The file transfer server 13 records the file list associated with the communication terminal 11, and then transmits the folder list included in the file list to the communication terminal 11. In this example, since the file list FL2 contains the folder (folder002), this information is transmitted to the communication terminal 11.

Subsequently, the communication terminal 11 requests the file transfer server 13 to refer to the file information of "folder002" (step S7). In response to this request, the file transfer server 13 returns the file list FL3 of "folder002" stored in the file list database 104. This makes it possible to list the files in "folder002" on the communication terminal 11.

Next, the communication terminal 11 sends an acquisition request for the file (file004.pdf) included in the referenced file list to the file transfer server 13 (step S8).

The file transfer server 13 that receives this acquisition request confirms from which file transfer server the file to be requested is registered in the file list acquired. That is, in this example, since the file (file004.pdf) is registered in the file list acquired from the file transfer server 23, the file transfer server 23 is specified as the file request destination.

In the file list FL2 shown in the figure, only the file list corresponding to the file transfer server 23 is recorded. However, when the communication terminal 11 makes a list request to the plurality of file transfer servers in the same manner as in step S6, a list corresponding to the plurality of file transfer servers is added to this file list FL2.

Next, the file transfer server 13 sends a connection request command (INVITE method) to the file transfer server 23 specified as the file request destination to the SIP server 4 (step S8.1). In this INVITE method, the account (SIP: relay-sever2@sip.srv) of the relay server 23 of the connection request destination is specified. The SIP server 4 acquires the global IP address of the file transfer server 23 by referring to the account information database 43. Then, the SIP server 4 relays the INVITE method transmitted from the file transfer server 13 to the file transfer server 23.

In this way, when the connection request command is transmitted from the file transfer server 13 to the file transfer server 23, the OK response is transferred from the file transfer server 23 to the file transfer server 13 via the SIP server 4. In this way, when the connection request command is accepted, a media session is established between the file transfer servers 13 and 23 (step S8.2).

When the media session is established, the file transfer server 13 instructs the file transfer server 23 to acquire the file. The file transfer server 23 follows this instruction to acquire the file from the file server 22 (step S8.2.1). That is, the file transfer server 23 acquires the file (file004.pdf) stored in the shared folder (folder002) of the file server 22. Then, the file transfer server 23 transfers the file acquired from the file server 22 to the file transfer server 13 by using the media session.

When the file transfer server 13 receives the file from the file transfer server 23, the file transfer server 13 sends a session end request (BYE) to the file transfer server 23 (step S8.3). This disconnects the media session between the file transfer servers.

Then, the file transfer server 13 transmits the file (file004.pdf) received from the file transfer server 23 to the communication terminal 11. In this way, the communication terminal 11 can acquire the file shared by LAN2 at a remote location. In the above, communication between the communication terminal 11 and the file transfer server 13 and between the file transfer server 23 and the file server 22 may use a protocol such as NFS or SMB.

As described above, when the file transfer server sends a SUBSCRIBE method to another file transfer server and makes a file list transfer request, the file transfer server that receives the transfer request continuously receives the file list. Send change notification and updated list to requester. In other words, when a file shared in the LAN to which the own device is connected is added or deleted, the update information is sent to the requester. Then, the file transfer server that transmits SUBSCRIBE and makes a transfer request manages the transmitted file list in association with the communication terminal of the request source. Therefore, the communication terminal can refer to the shared file list dedicated to its own device no matter when the file transfer server is accessed after that (the period during which SUBSCRIBE is valid).

Next, the file search process will be described. At a certain timing, the communication terminal 11 makes a file search request to the file transfer server 13 (step S9). As shown in the figure, this search request includes the file to be searched (file00C.pdf) and the file transfer servers 23 and 53 (SIP: relay-server2@sip.srv and SIP: relay-server3 @ sip) to be searched. .srv) is specified.

In this embodiment, the file transfer server of the search destination is specified by the communication terminal 11 of the search request source, but the file transfer server of the search destination may be set to the file transfer server 13 in advance. Good. In this case, the communication terminal need only specify the search target file. The file transfer server makes a search request to a preset file transfer server.

The file transfer server 13 first makes a file list acquisition request (SUBSCRIBE) to the file transfer server 23 according to the designation of the communication terminal 11 (step S9.1). The file transfer server 23 returns the file list FL4 in response to this. In addition, after step S9, the processing is described separately from the processing before step S8. If SUBSCRIBE in step S6 is still valid, the process in step S9.1 is unnecessary. This is because the latest file list is always sent from the file transfer server 23 to the file transfer server 13 after step S6.

Similarly, the file transfer server 13 requests the file transfer server 53 to acquire the file list (step S9.2). The file transfer server 53 returns the file list FL5. In this file list FL5, three files (file00A to file00C.pdf) stored in the shared folder (folder003) of the file server 52 are recorded.

The file transfer server 13 searches the file list acquired from each of the file transfer servers 23 and 53, and confirms the existence of the file to be searched (file00C.pdf). Here, since the file to be searched (file00C.pdf) exists in the file list FL5 acquired from the file transfer server 53, the file list FL6 is returned to the communication terminal 11.

Next, the communication terminal 11 sends an acquisition request for the file (file00C.pdf) recorded in the acquired file list to the file transfer server 13 (step S10).

Upon receiving this acquisition request, the file transfer server 13 sends a connection request command (INVITE method) (step S10.1) and establishes a media session between the file transfer servers 13 and 53 (step S10.2). Then, the file transfer server 13 issues a file acquisition instruction to the file transfer server 53. The file transfer server 53 acquires a file (file00C.pdf) from the file server 52 according to this instruction (step S10.2.1). Then, the file transfer server 53 transfers the file acquired from the file server 52 to the file transfer server 13 by using the media session. Subsequently, the file transfer server 13 sends a session end request (BYE) to the file transfer server 53 (step S10.3).

Then, the file transfer server 13 transmits the file (file00C.pdf) received from the file transfer server 53 to the communication terminal 11. In this way, the communication terminal 11 can acquire the file shared by LAN2 at a remote location by designating the file name as the search target. In the above, the communication between the communication terminal 11 and the file transfer server 13 and the communication between the file transfer server 53 and the file server 52 may use a protocol such as NFS or SMB.

As described above, according to the present invention, it is possible to share files between LANs in remote locations beyond the Internet and the like. Then, the file list acquired from the file transfer server of another LAN is stored in the file transfer server in the LAN and cannot be referred to from the outside, so that it is safe. In other words, each terminal connected to the LAN does not directly refer to the file list shared in different LANs, but by referring to the file list acquired by the file transfer server, as if it were a remote LAN. You can use it as if you were sharing a file.

Further, the file list acquired by the file transfer server is managed in association with the communication terminal of the request source. In the above embodiment, the case where the file transfer server 13 manages the file list dedicated to the communication terminal 11 has been described as an example. Similarly, the file transfer server 13 has a plurality of communication terminals connected to the LAN 1. , It manages a dedicated file list for each. Therefore, each communication terminal can exclusively use, for example, a frequently referenced shared file list. Furthermore, by specifying a search file on the communication terminal, the file transfer server finds the search target from the file list shared by other LANs and provides the result. This makes it possible to search for and use files that exist on other LANs beyond the Internet.

<figref num="1">It is a network block diagram of the communication system which concerns on this embodiment.</figref><figref num="2">It is a functional block diagram of a file transfer server.</figref><figref num="3">It is a functional block diagram of a SIP server.</figref><figref num="4">It is a sequence diagram of communication processing.</figref><figref num="5">It is a sequence diagram of communication processing.</figref><figref num="6">It is a sequence diagram of communication processing.</figref>

Code description

1,2,5 LAN (local network) 3 Internet (global network) 4 SIP server 11,21,51 Communication terminal 12,22,52 File server 13,23,53 File transfer server