JP4527523B2 - Server selection method, server selection method, server, and client terminal - Google Patents

Description

  The present invention relates to a server selection method, a server selection method, a server, and a client terminal, and in particular, a server selection method and a server that can efficiently select a connectable server from a plurality of servers that provide the same service. The present invention relates to a selection method, a server, and a client terminal.

  If a failure occurs on the network or server side during communication between the client terminal and the server, the client terminal application detects the failure by a response timeout or the like. In the case where there are a plurality of servers providing the same service, conventionally, a user connected to another server based on an error message of a client terminal and continued to receive the service.

  However, this method has a problem in that the user's manual work is required, which is troublesome and the operation is complicated.

  Therefore, in order to solve this problem, a method has been devised in which, when a failure is detected at a client terminal, the user is not aware of the occurrence of the failure (see, for example, Patent Document 1). That is, a server switching method has been devised that can automatically switch to another service providing server and transmit data from the disconnected data position when a failure is detected at the client terminal.

  The server switching method described in this publication includes the following procedure. First, the client terminal obtains the IP address of the server that provides the same service from the WWW server, and registers the storage device in the apparatus with priority. When receiving a service, the client terminal selects at least two servers having a high priority and issues a connection request, and selects the server with the fastest response and receives data. When the client terminal detects a failure during data reception, the client terminal requests data reception from the remaining connected servers, and receives data from the server that responded earliest.

  FIG. 7 is a diagram illustrating a signal sequence between the client terminal and the server.

  As can be seen from FIG. 7, assuming that there are two servers providing the same service, the client terminal first issues a connection request to each server (S81, S82). Server 1 and server 2 each return a response (S83, S84). When the server 1 responds quickly, the client terminal issues a data transmission request as a service request to the server 1 (S85). When receiving the response (S86), the client terminal starts data reception (S87).

  Thus, according to the invention of this publication, when a failure is detected at the client terminal, it is possible to automatically switch to another service providing server without making the user aware of the occurrence of the failure. In addition, since the client terminal is always connected to a plurality of servers, there is a high probability that data can be received immediately when the server is switched.

JP 2000-99435 A

  The problem with the above-described publication invention is that it takes time to select a server when switching the server of the client terminal. The reason is that when a client terminal selects a server, it must select a plurality of normal and high priority servers from the server information held by itself and issue a connection request to each of them.

  An object of the present invention is to provide a server selection method, a server selection method, a server, and a client terminal in which the server selection processing time during server switching of the client terminal, which is the above-described conventional problem, is improved.

Another server selection method of the present invention is a server selection method in a system in which a plurality of servers providing the same service as a client terminal are connected via a network, wherein the client terminal requests a connection request by a multicast packet to the plurality of servers. When the plurality of servers receive the multicast packet, each of them returns a response packet to the client terminal, and the client terminal receives the response packet from the plurality of servers earliest when a failure occurs in the server or the network. The service providing server is switched to the server that has returned the response packet.

  The multicast packet also includes a service type, and the server activates the service corresponding to the service type when the multicast packet is received.

  The server may rewrite the source address of the response packet with its own unicast address and send the response packet to the client terminal.

Another server selection method of the present invention is a server selection method in a system in which a plurality of servers providing the same service as a client terminal are connected via a network, wherein the client terminal requests a connection request by a multicast packet to the plurality of servers. And a server selection unit that switches a service providing server to the server that has returned the response packet earliest when a response packet is received from the plurality of servers when a failure occurs in the server or the network. The plurality of servers each include a second service processing unit that, when receiving the multicast packet, returns a response packet to the client terminal.

  The multicast packet includes a service type, and the second service processing unit activates a service corresponding to the service type when the multicast packet is received.

  The server may include an address conversion unit that rewrites the source address of the response packet to its own unicast address when the response packet is sent to the client terminal.

The client terminal of the present invention returns the response packet as soon as possible when receiving a response packet from the plurality of servers when a failure occurs in the server or the network, and a first service processing unit that makes a connection request to the plurality of servers by a multicast packet The server includes a server selection unit that switches a service providing server to the server.

  The present invention has an effect of improving the server selection processing time of the client terminal. The reason is that a client terminal can make a connection request with a single multicast address to a plurality of servers providing the same service.

  Next, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a system configuration diagram showing an embodiment of the present invention, and FIG. 2 is an operation explanatory diagram thereof.

  Referring to FIG. 1, an embodiment of the present invention shows a client terminal 1 that is a service receiving side, and servers (server 2 to server 4) that provide the same service. These are connected via the network 9. The server belongs to a member of the same multicast address.

  In FIG. 1, the client terminal 1 multicasts a service request packet, which is a connection request to the server, to the server as a first packet. As a result, the packet reaches all the servers registered in the multicast. That is, the client terminal 1 accesses all servers that provide the same service using multicast, and starts communication with the server that has the fastest response from the response.

  As a result, communication can be established when even one identical service providing server is alive.

  Next, the operation of the system of FIG. 1 will be described with reference to FIG.

  In FIG. 2, in order for the client terminal 1 to receive a specific service, a packet in which a destination address is set as a multicast address is multicast to the server. Thereby, a connection request packet can be simultaneously sent to a plurality of servers (server 2, server 3, server 4) providing the same service (S11 to S13).

  When the server receives the packet, the server recognizes from the destination address that the request is a multicast connection request, and determines whether the service request included in the packet can be handled. The server ignores the request if the service request contained in the packet is not available. If the service corresponds to the service request, the server rewrites the source address of the response packet with its own unicast address and sends the response packet to the terminal (FIGS. 2, S14, S15, and S16).

  The client terminal 1 receiving the response packet receives as many response packets as the number of servers (FIGS. 2, S14, S15, and S16). The client terminal receives only the response packet of the server with the fastest response, and discards other slow response packets as they are.

  The client terminal obtains the other party's unicast address from the source address of the response packet to be received, and uses it as the destination address to perform subsequent communications (FIG. 2, S17, S18).

  FIG. 3 is a block diagram showing an embodiment of the client terminal 41 of the present invention.

  As can be seen from FIG. 3, the client terminal 41 includes a service processing unit 42, a server selection unit 43, and a network communication unit 44.

  The service processing unit 42 performs multicast for server selection on the server. When the server selection unit 43 selects a server, the service processing unit 42 processes information provided from the selected server.

  The server selection unit 43 performs a process of selecting one server when response packets are returned from a plurality of servers during multicast for starting server selection.

  The network communication unit 44 performs processing for transmitting a packet from the service processing unit 42 via the Internet 45 and receiving a packet from the server.

  The Internet 45 is a network that connects the client terminal 1 and a plurality of servers.

  FIG. 4 is a block diagram showing an embodiment of the server 51 of the present invention.

  As can be seen from FIG. 4, the server 51 includes a service processing unit 52, an address conversion unit 53, and a network communication unit 54.

  The service processing unit 52 is a part that receives a service request by multicast from a client terminal and provides a service to the client terminal.

  The address conversion unit 53 performs processing for converting the source address of the response packet of the multicast packet coming from the client terminal into its own address.

  The network communication unit 54 performs processing for transmitting the packet from the service processing unit 52 and receiving the packet from the client terminal via the Internet 45.

  FIG. 5 is an operation flowchart showing an embodiment of the present invention.

  First, in S61, the client terminal starts a service request toward the server providing the service.

  In S62, the client terminal multicasts the service request packet using the destination address of the service request packet as the multicast address.

  This service request packet is a connection request to the server and also includes the service type requested by the terminal.

  In S63, the server receives a service request packet from the client terminal.

  In S64, the server that has received the service request activates a service of that service type.

  In S65, the server determines whether the original packet is multicast when sending a response packet to the service request packet.

  If the original packet is multicast, in S66, the own address is converted into a source address and set as a response packet.

  If the original packet is not multicast, there is no need to convert the address, so a service response is made as it is (to S67).

  In S67, a response packet is transmitted to the client terminal that transmitted the service request.

  In S68, the client terminal receives the response packet.

  In S69, the client terminal determines whether it is the response packet received earliest.

  That is, when a response packet is received, the process proceeds to S70 if it is the first received response packet, and to S71 if it is the second or later received response packet.

  In S70, the client terminal receives a service as usual using the server that transmitted the response packet as the communication partner.

  In S71, the client terminal discards the second and subsequent response packets. And it does not communicate with those servers. Note that the server that has discarded the response packet does not receive a service execution request from the client terminal, and therefore needs to disconnect the path after a certain period of time.

  FIG. 6 is a diagram showing a signal sequence between the client terminal and the server in the present invention.

  As can be seen from FIG. 6, it is assumed that there are two servers that provide the same service. First, the client terminal uses the destination address of the service request packet as a multicast address to multicast the service request packet (S91). Server 1 responds (S92), and server 2 also responds (S93). When the server 1 responds quickly, the client terminal communicates with the server 1 and receives service provision from the server 1 (S94).

  As can be seen from FIG. 6, in this embodiment, the service request packet is multicast. Therefore, it is possible to issue a service request to servers (two servers in FIG. 6) that provide the same service in one step. Also, the service type is specified at the same time when multicasting the service request packet. For this reason, when the client terminal receives the response packet, the service compatible application of the server is already activated. Therefore, when the client terminal receives the response packet, it can immediately start communication for information reception. As a result, in this embodiment, as can be seen from FIG. 6, four steps are required from service request by multicast to service communication.

  On the other hand, in the signal sequence between the client terminal and the server according to Japanese Patent Laid-Open No. 2000-99435 described in the background art, as shown in FIG. 7, 7 steps are required, which is increased by 3 steps from FIG. This is because, in the method of the publication, the client terminal must issue a connection request for each server, and makes a service request to the server 1 after detecting the response of the server 1.

  That is, in FIG. 6, the connection request by the client terminal is only one step of S91 by multicast. On the other hand, in FIG. 7, since the client terminal individually issues a connection request, two steps S81 and S82 are required, which is increased by one step compared to FIG. In FIG. 6, the service type is also specified at the time of multicasting in S91, whereas in FIG. 7, a service request is made after a response to the connection request is returned. Accordingly, in this case, in FIG. 7, the two steps S85 and S86 are increments compared to FIG. As a result, in FIG. 7, the number of steps increases by 3 steps compared to FIG.

  As described above, the present invention has an effect that the server selection processing time of the client terminal is improved. The reason is that a client terminal can make a connection request with a single multicast address to a plurality of servers providing the same service.

  The present invention further has an effect of improving the utilization efficiency of the storage device of the client terminal.

  The reason is that since the client terminal selects a server using multicast, it is not necessary to store the IP address of the server in the storage device in the apparatus.

  The present invention has an effect that the steps until the client terminal reaches communication for data reception with the server can be reduced. This is because the service type can be specified at the same time when multicasting the service request packet of the client terminal.

1 is a system configuration diagram showing an embodiment of the present invention. It is operation | movement explanatory drawing which shows one embodiment of this invention. It is a block diagram which shows one Embodiment of the client terminal 41 of this invention. It is a block diagram which shows one Embodiment of the server 51 of this invention. It is an operation | movement flowchart which shows one embodiment of this invention. It is a figure which shows the signal sequence of the client terminal and server in this invention. It is a figure which shows the signal sequence of the conventional client terminal and a server.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Client terminal 2 Server 3 Server 4 Server 41 Client terminal 42 Service processing part 43 Server selection part 44 Network communication part 45 Internet 51 Server 52 Service processing part 53 Address conversion part 54 Network communication part

Claims (5)

In a server selection method in a system in which a plurality of servers providing the same service as a client terminal are connected via a network,
The client terminal makes a connection request to the plurality of servers by a multicast packet, and when the plurality of servers receive the multicast packet, each of them returns a response packet to the client terminal. When the response packet is received from the plurality of servers, the service providing server is switched to the server that has returned the response packet earliest ,
The multicast packet includes a service type, and the server activates a service corresponding to the service type when the multicast packet is received . 2. The server selection method according to claim 1, wherein the server rewrites the source address of the response packet with its own unicast address and sends the response packet to the client terminal. In the server selection method in a system in which multiple servers providing the same service as the client terminal are connected via a network,
  A first service processing unit that makes a connection request to the plurality of servers by a multicast packet; and the server that has returned the response packet earliest when a response packet is received from the plurality of servers when a failure occurs in the server or the network. And a server selection unit that switches service providing servers, and the plurality of servers each include a second service processing unit that returns a response packet to the client terminal when receiving the multicast packet,
  The multicast packet includes a service type, and the second service processing unit activates the service corresponding to the service type when the multicast packet is received. 5. The server selection method according to claim 4, wherein the server includes an address conversion unit that rewrites the source address of the response packet to its own unicast address when sending the response packet to the client terminal. A first service processing unit that makes a connection request to a plurality of servers by a multicast packet including a service type; and the plurality of servers that start a service corresponding to the service type when a failure occurs in the server or the network when the multicast packet is received And a server selection unit that switches a service providing server to the server that has returned the response packet earliest when receiving a response packet from the server.

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