KR100717239B1 - Method and apparatus for providing reliable communication between member servers belonging to the same multicast group - Google Patents

Abstract

The present invention is to ensure reliable communication between member servers belonging to the same multicast group, and a method for providing reliable communication according to the present invention includes a server sequence storage unit of a first member server belonging to the multicast group. Maintaining a first server sequence corresponding to the first member server and stored server sequences corresponding to each of the other member servers belonging to the same multicast group as the first member server in the other member belonging to the multicast group. Transmitting a multicast message to member servers, including the first server identifier and the first server sequence identifying the first member server in the multicast message, each time the multicast message is transmitted. The first server held in the server sequence storage unit Increasing the sequence by a predetermined value, wherein a final sequence notification message is received from a second member server belonging to the same multicast group as the member server, wherein the final sequence notification message is a second server identifier of the second member server and the second; And a second server sequence corresponding to the member server, the second server identifier corresponding to the second server identifier stored in the server sequence storage with reference to the second server identifier included in the final sequence notification message. Identifying a stored server sequence, and if the second server sequence is greater than or equal to a sum of a predetermined value with the second stored server sequence, sending the predetermined member to the second stored server sequence in the second stored server sequence. Requesting retransmission of the multicast message corresponding to the server sequence sum of The.

Multicast, UDP, Resend Request, Acknowledgment Message, Server Sequence

Description

 METHOD AND APPARATUS FOR PROVIDING RELIABLE COMMUNICATION BETWEEN MEMBER SERVERS BELONGING TO SAME MULTICAST GROUP}

1 is a diagram illustrating a network connection of user terminals accessing a plurality of service servers according to the related art.

2 is a diagram illustrating a network connection of a location server and a service server for managing location information of users according to the related art.

3 is a diagram illustrating a network connection between a plurality of location servers, a service server, and a user terminal configured in a multicast group according to the present invention.

4 illustrates an embodiment of a communication providing method according to the prior art.

5 illustrates another embodiment of a communication providing method according to the prior art.

6 illustrates network connections of a plurality of location servers included in the same multicast group in accordance with the present invention.

7 is a diagram illustrating a process of receiving and processing a final sequence notification message in a member server according to the present invention.

8 is a diagram illustrating a process of receiving and processing a multicast message in a member server according to the present invention.

9 illustrates an embodiment for providing a reliable communication method between member servers according to the present invention.

10 illustrates another embodiment for providing a reliable communication method between member servers according to the present invention.

11 is a block diagram illustrating a configuration of a member server for providing reliable communication according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1101: server sequence storage unit 1102: message transmission unit

1103: server sequence management unit 1104: message receiving unit

1105: server sequence search unit 1106: retransmission request unit

1107: message search unit

The present invention relates to a method and apparatus for providing communication for ensuring reliable communication between member servers belonging to the same multicast group, and more particularly, to each member server belonging to a multicast group corresponding to each of the other member servers. A method and apparatus for maintaining a server sequence to provide reliable communication between member servers.

1 is a diagram illustrating a network connection of user terminals accessing a plurality of service servers according to the related art.

In Fig. 1, a user who uses the user PCs 101 and 102 connects to the game servers 104, 105, and 106 that provide an online game that she wants to play through the Internet 103. For example, game servers 104 and 105 may provide high-stop game services, and game server 106 may provide hula game services. At this time, the login / logout of the user is performed separately in each game server 104, 105, and 106, and the login / logout information of the user is separately managed in each game server 104, 105, and 106. Thus, in the prior art, a user logged in to one game server has no knowledge of the current state of the user logged in to another game server (e.g., whether he is logged in or logged out, or what game he is playing).

2 is a diagram illustrating a network connection between a location server and a service server for managing location information of users according to the related art.

In order to solve the problem of the configuration illustrated in FIG. 1, a location server 207 capable of intensively managing login / logout information of users in all game servers 204, 205, and 206 is proposed. It became. When users access the game servers 204, 205, 206 that provide the online games they want to play via their user PCs 201, 202 and the Internet 103, the game servers 204, 205, 206 ) Sends the user's login / logout information to the location server 207. Then, the location server 207 centrally manages the login / logout information of the users in all the game servers 204, 205, and 206, so that the status of the users logged into any game server can be provided to the user. Will be.

However, currently provided online games are provided by hundreds of game servers, and if one attempts to manage the login / logout information managed by each of these game servers in one location server, the system for the location server The problem arises that the load of is too large.

Therefore, in order to solve the problem of system load concentrated on the location server, a method of configuring the location server into a multicast group is proposed. 3 is a diagram illustrating a network connection between a plurality of location servers, a service server, and a user terminal configured as a multicast group according to the present invention. Location servers belonging to the multicast group should have the same status information in relation to the user's login / logout status.

Therefore, when location servers belonging to the multicast group have the same status information with respect to the login / logout status of the user, when one location server belonging to the multicast group receives the login / logout message of the user, In response to receiving the login / logout message, a multicast message is generated and transmitted to other location servers belonging to the same group.

 However, when using a communication environment in which reliability is not guaranteed, such as UDP (User Datagram Protocol) communication, the message may be lost during the exchange of the message. Since reliable communication between location servers is very important, there is an urgent need to develop a method and apparatus for providing reliable communication between location servers even when the medium and communication means used for message transmission do not guarantee reliable communication. Is requested.

4 is a diagram illustrating an embodiment of a communication providing method according to the prior art. Referring to FIG. 4, the first server 401 may be networked with the second server 402 to transmit and receive a predetermined message. However, in the UDP communication environment of the prior art, there is a problem that the message may be lost during transmission and reception.

For example, the first server 401 transmits the message 1, the message 2, and the message 3 to the second server 402 in turn, and finally sends the message 4, but the message 4 is lost in the transmission process and thus the second server. There may be a problem that is not delivered to 402.

In this case, when the first server 401 transmits the message 5 to the second server, the second server determines that the message 4 is lost and requests the first server 401 to retransmit. The first server 401 retransmits the message 4 to the second server 402 according to the retransmission request. However, the retransmission of such a lost message can be applied when exchanging messages between two servers, and when there are a plurality of servers belonging to the same group as described above, when some of the messages exchanged between the plurality of servers are lost. There is a problem that does not apply to.

In addition, FIG. 4 illustrates a case in which a lost message is a message in the middle of a message having a sequence number, that is, a message 4 between a message 3 and a message 5 is lost, a request for retransmission by determining whether the message is lost, or a series of If the last message of the message having the sequence number is lost, there is a problem that cannot be processed in the above manner.

5 is a view showing another embodiment of a communication providing method according to the prior art. Referring to FIG. 5, the first server 501 may be networked with the second server 502 to transmit and receive a predetermined message. However, when the last message transmitted from the first server 501 to the second server 502 is lost in the prior art UDP communication environment, the second server cannot determine this and cannot request retransmission to the first server. There was this.

For example, the first server 501 transmits the message 1, the message 2, and the message 3 to the second server 502 in sequence, and finally sends the message 4, but the message 4 is lost in the transmission process and thus the second server. There may be a problem that is not delivered to 502.

In this case, the second server 502 does not recognize that the message 4 is lost, or if another message is received after a considerable time has elapsed, the first server 501 and the second server 502. There is a problem of inconsistency between data and state.

Therefore, there is an urgent need to develop a communication providing method or device for improving the unreliable communication environment as described above to reliably implement the transmission and reception of messages between servers so that data and states between location servers belonging to the same group can be kept the same. Is requested.

It is an object of the present invention to provide a communication providing method or apparatus for reliably implementing transmission and reception of messages between servers so that data and states between location servers belonging to the same multicast group can be kept the same.

The present invention also provides a first member server that transmits a multicast message to other member servers among member servers belonging to the same multicast group to transmit a final sequence notification message confirming receipt of the multicast message to the other member servers. Thus, other member servers check for missing multicast messages and, if lost, request retransmission so that member servers belonging to the same multicast group send and receive messages to each other to determine the lost messages and retransmit them. By doing so, it is another object to provide reliable communication.

In addition, according to the present invention, the first server transmitting the multicast message transmits a final sequence notification message including the first server identifier and the first server sequence to other member servers at regular time intervals, whereby the first server transmits the multicast message. After transmitting, even if other multicast messages are not transmitted to other servers for a predetermined period of time, other servers can determine that the message corresponding to the first server sequence is lost and request retransmission to provide reliable communication. To do it for another purpose.

In addition, the present invention by determining the sequence of the transmitted message to determine whether the message is lost, by requesting the retransmission to receive the error, to prevent errors due to the lost message, the message is transmitted in a reliable communication method between member servers belonging to the same group Another purpose is to allow transmission and reception.

Another object of the present invention is to provide reliable communication by requesting retransmission by determining that the other member server determines that the last message transmitted by one member server belonging to the same group is lost.

In order to achieve the above object and to solve the above-mentioned problems of the prior art, in a method for providing reliable communication between member servers belonging to the same multicast group according to an embodiment of the present invention, the multicast group Maintain a first server sequence corresponding to the first member server and stored server sequences corresponding to each of the other member servers belonging to the same multicast group as the first member server in a server sequence storage of a first member server belonging to And when the multicast message is transmitted to the other member servers belonging to the multicast group, the multicast message includes a first server identifier identifying the first member server and the first server sequence. Step, each time the server transmits the multicast message, the server sequence Incrementing the first server sequence held in the second storage unit by a predetermined value, and a final sequence notification message from a second member server belonging to the same multicast group as the member server, wherein the final sequence notification message is the second member. And a second server identifier of a server and a second server sequence corresponding to the second member server, stored in the server sequence storage with reference to the second server identifier included in the final sequence notification message. Identifying a second stored server sequence corresponding to the second server identifier, and when the second server sequence is greater than or equal to a sum of a predetermined value to the second stored server sequence, the second member server. A multicast mesh corresponding to the server sequence obtained by adding the predetermined value to the second stored server sequence. A step of requesting retransmission.

In addition, a method for providing reliable communication between member servers belonging to a group according to another embodiment of the present invention may include a server corresponding to the first member server in a server sequence storage of a first member server belonging to the group. Maintaining a first server sequence and stored server sequences corresponding to each of the other member servers, the first server identifying the first member server in the message when sending a message to the other member servers belonging to the group; Transmitting, including an identifier and the first server sequence, increasing the first server sequence held in the server sequence storage by a predetermined value each time the message is transmitted, and at a predetermined time interval. 1 A first server identifier identifying a member server and a first server stored in said server sequence storage. Sending to the other member servers a final sequence notification message comprising a burr sequence.

In addition, in a first member server for providing reliable communication with other member servers belonging to one group according to another embodiment of the present invention, the first server sequence corresponding to the first member server and the other A server sequence storage unit for storing stored server sequences corresponding to each of the member servers, a first server identifier identifying the first member server in the message when the message is sent to the other member servers belonging to the group; A message transmitter including a first server sequence, and a server sequence manager configured to increase the first server sequence held by the server sequence storage by a predetermined value each time the message is transmitted.

Hereinafter, a method and apparatus for providing reliable communication according to the present invention will be described in detail with reference to the accompanying drawings.

6 is a diagram illustrating network connections of a plurality of location servers included in the same multicast group according to the present invention. Referring to FIG. 6, the first server 600, the second server 610, the third server 620, and the fourth server 630 may be included in the same multicast group and connected to a network. Member servers included in the same multicast group may store and maintain their own server sequence and server sequences of other member servers included in the same multicast group in the server sequence storage of each member server. For example, a first server 600, which is a first member server among member servers included in the same multicast group, may be stored in the server sequence storage unit as shown by reference numeral 600 in the first server and other member servers belonging to the same multicast group. Server sequences corresponding to each of the fields 610, 620, and 630 may be stored.

For example, the first server 600 may store the sequence "15" of the first server 600, the sequence "15" of the second server 610, and the third server 620 in the server sequence storage unit 601. Store and maintain sequence " 15 " and sequence " 15 " The server sequence is a sequence related to message transmission and reception between member servers included in the same multicast group.

The first server 600, which is one of the member servers belonging to the same multicast group, transmits the multicast message to the other member servers 610, 620, and 630 belonging to the multicast group. The first server 600 includes a first server identifier and a first server sequence that identify the server and transmit the same.

When member servers belonging to the same multicast group receive a predetermined message from an external server in order to synchronize data stored in the servers, the member servers generate a multicast message and transmit the same to other member servers. Other member servers receive multicast messages to synchronize data.

When the first server 600 transmits such a multicast message to other member servers 610, 620, and 630 belonging to the same multicast group, the first server 600 includes a first server identifier and a first server sequence in the multicast message. Including to send.

Each time the first server 600 transmits the multicast message, the first server sequence increases the first server sequence held in the server sequence storage unit 601 by a predetermined value and increases the first server sequence by the predetermined value. May be included in the multicast message 602 and transmitted. For example, each time the first server 600 transmits a multicast message, the first server 600 increments the first server sequence maintained in the sequence storage unit 601 by “1”, and as shown by reference numeral 602. A first server identifier "LCS 1" and an incremented first server sequence "16" are transmitted to other member servers 610, 620, and 630. The increasing value may be variously set according to an embodiment.

Also, according to an embodiment, the first server 600 may include the first server sequence maintained in the server sequence 601 in the multicast message and transmit the first server sequence, and increase the first server sequence by a predetermined value. For example, referring to reference numeral 603, as the first server transmits a multicast message, the first server sequence “15” maintained in the server sequence storage unit 601 is increased by “1” to “16”. Let's do it.

As described above, the first server transmits a multicast message including a first server sequence and increases the first server sequence by a predetermined value, or increases the first server sequence by a predetermined value, and then first server sequence. Since both multicast messages can be transmitted, and both cases are the same in that the first server sequence is increased by a predetermined value every time the multicast message is transmitted, all of the above embodiments belong to the present invention or the equivalent range. Mine However, in the former case (when the first server transmits a multicast message including the first server sequence and increases the first server sequence by a predetermined value), the server sequence included in the final sequence notification message to be described later is The predetermined value is reduced in the first server sequence stored in the server sequence storage of the first server 600. Likewise, in the latter case (when the first server increases the first server sequence by a predetermined value and then transmits a multicast message including the first server sequence), the server sequence included in the final sequence notification message to be described later is described in the above-mentioned. The first server sequence is stored in the server sequence storage of the first server 600.

The first server 600 which has transmitted the multicast message may receive a final sequence notification message including a first server identifier identifying the first server at a predetermined time interval and a first server sequence stored in the server sequence storage. It transmits to other member servers 610, 620, and 630 belonging to the same multicast group as the member server. The predetermined time interval may also be changed to various values according to the embodiment.

For example, when the first server 600 transmits a multicast message including the first server sequence after increasing the first server sequence by a predetermined value, the first server 600 may be “at 5 second” intervals. Other member servers 610 and 620 belonging to the same multicast group to the final sequence notification message 604 including the first server identifier " LCS 1 " and the first server sequence " 16 " stored in the server sequence storage 603; 630).

Meanwhile, the first server 600 transmits a multicast message including the first server sequence "15" stored in the server sequence storage unit 603 and increases the stored first server sequence by a predetermined value to "16". When recording, the first server 600 belongs to the same multicast group by including a "15" in the final sequence notification message 604, which is a server sequence reduced by a predetermined value from the stored first server sequence "16". And transmits to other member servers 610, 620, and 630. Even in this case, the first server 600 transmits the final sequence notification message including the server sequence and the server identifier included in the multicast message transmitted by the first server 600 to the other member servers 610, 620, and 630. same.

When the other member servers 610, 620, and 630 belonging to the multicast group receive the final sequence notification message, the server sequence storage unit of each member server refers to the first server identifier included in the final sequence notification message. Identifies a first stored server sequence corresponding to the first server identifier stored in. As described above, each member server belonging to the multicast group includes a server sequence storage unit, and the server sequence storage unit maintains a server identifier and a server sequence of each member server belonging to the multicast group.

If the first server sequence stored in the member server is greater than or equal to the sum of the predetermined value in the first stored server sequence, the first member server adds the predetermined value to the first stored server sequence. Request retransmission of the multicast message corresponding to the sequence. The above process is described in detail with reference to FIG. 7 as follows.

7 is a diagram illustrating a process of receiving and processing a final sequence notification message in a member server according to the present invention. Referring to FIG. 7, the first server 700, the second server 710, the third server 720, and the fourth server 730 are included in the same multicast group to synchronize data.

The first server 700, which is the first member server among the member servers belonging to the same multicast group, receives the final sequence notification message from one of the second member servers 710, 720, and 730 belonging to the same multicast group. The process of transmitting the final sequence notification message by the second member server has been described with reference to FIG. 6.

The final sequence notification message includes a server identifier of the second member server and a second server sequence corresponding to the second member server. For example, in FIG. 7, the fourth server 730 transmits a final sequence notification message 702 to the first server 700. The final sequence notification message 702 includes a server identifier "LCS 4" of the fourth server 730 and a server sequence "16" corresponding to the fourth server 730.

The first server 700 refers to the server identifier "LCS 4" included in the received final sequence notification message 702 and stores the stored server sequence corresponding to the server identifier "LCS 4" stored in the server sequence storage unit 701. Identifies For example, the stored server sequence may be "15".

When the server sequence included in the final sequence notification message 702 is greater than or equal to the sum of a predetermined value with the server sequence stored in the server sequence storage unit 701, the first server 700 may notify the fourth server. A retransmission of the multicast message corresponding to the server sequence obtained by adding a predetermined value to the stored server sequence is requested.

For example, the server sequence "16" included in the final sequence notification message 702 received by the first server 700 is "1" which is a predetermined value in the server sequence "15" stored in the server sequence storage unit 701. In this case, the first server 700 requests retransmission of the multicast message corresponding to the server sequence obtained by adding the predetermined value "1" to the stored "15" to the fourth server 730. Send a message 703.

Therefore, according to the present invention, a server which transmits a multicast message to other member servers among member servers belonging to the same multicast group transmits a final sequence notification message confirming reception of the multicast message to the other member servers. In addition, other member servers check for missing multicast messages and request retransmission if they are lost.

Therefore, according to the present invention, when member servers belonging to the same multicast group transmit and receive messages to each other, the lost messages are determined to request retransmission, thereby providing reliable communication.

In particular, the first server transmitting the multicast message transmits a final sequence notification message including the first server identifier and the first server sequence to other member servers at regular time intervals, whereby the first server transmits the multicast message. Thereafter, even if other multicast messages are not transmitted to other servers for a predetermined period of time, other servers can determine that the message corresponding to the first server sequence is lost and request retransmission. This effect will be described later in detail with reference to FIG.

8 is a diagram illustrating a process of receiving and processing a multicast message in a member server according to the present invention.

Referring to FIG. 8, the first server 800, the second server 810, the third server 820, and the fourth server 830 are included in the same multicast group to synchronize data.

The first server 800, which is the first member server among the member servers belonging to the same multicast group, receives the second multicast message from one of the second member servers 810, 820, and 830 belonging to the same multicast group. A message transmitted by one of the second member servers to the remaining member servers belonging to the same multicast group. For example, the second multicast message is one of the second member servers 810, 820, and 830. One may be a processed message received from an external server.

For example, when member servers belonging to the multicast group manage user login / logout information of an external service server, the member servers must keep the same in synchronization with the login / logout status for the user. One member server may generate a multicast message for receiving a login / logout message for the user from an external service server and transmitting it to the remaining member servers of the same group.

The first server 800 receives the multicast message 802 from the fourth server 830. The multicast message 802 includes a server identifier of a fourth server 830 that is a second member server and a server sequence corresponding to the fourth server. That is, the multicast message 802 may include a server identifier "LCS 4" of the fourth server 830 and a server sequence "17" corresponding to the fourth server.

The first server 800 identifies the second stored server sequence corresponding to the second server identifier stored in the server sequence storage unit by referring to the second server identifier included in the multicast message 802. For example, the first server 800 refers to the server identifier "LCS 4" of the fourth server 830 included in the multicast message 802, and stores the fourth server identifier "stored in the server sequence storage unit 801. Identifies the stored server sequence "15" corresponding to LCS 4 ".

When the second server sequence included in the multicast message is larger than the sum of a predetermined value with the second stored server sequence, the first server 800 informs the second member server of the second stored server sequence. A retransmission of the multicast message corresponding to the server sequence in which predetermined values are added is requested. For example, the first server 800 stores the server sequence "17" of the fourth server included in the received multicast message 802 in the server sequence storage unit 801. If greater than the sum of the predetermined values, the fourth server 830 requests retransmission of the multicast message corresponding to the server sequence obtained by adding the predetermined value to the server sequence of the fourth server. In one example, the predetermined value may be “1”, and the first server 800 may store the server sequence “15” of the fourth server in which the server sequence “17” of the fourth server included in the multicast message is stored. When larger than "16", which is the sum of "1", the retransmission request message 803 of the multicast message corresponding to the server sequence "16" is transmitted to the fourth server 830.

The retransmission request message 803 includes a server sequence for the multicast message that the fourth server should retransmit. In this example, the retransmission request message includes a server sequence "16" for the multicast message that the fourth server should retransmit.

The fourth server 830 receives the retransmission request message 803 from the first server, and stores the multicast message sent to the member servers 800, 810, and 820 in the message buffer 804. The multicast message corresponding to the sequence is retrieved and transmitted to the first server.

The message buffer 804 is a storage means for storing a multicast message transmitted by one of the member servers belonging to the same multicast group to the remaining member servers. Since the multicast message includes a server identifier and a server sequence to transmit, the fourth server 830 responds to receiving the retransmission request message 803, and thus the server sequence "16" included in the retransmission request message 803. The multicast message 805 corresponding to the message is retrieved from the message buffer 804 and transmitted to the first server 810.

Therefore, according to the present invention, when transmitting a multicast message having a continuous sequence from a member server belonging to the same multicast group to other member servers belonging to the same multicast group, the multi-message at the member server receiving the multicast message Since a multicast message that is lost and not transmitted among the cast messages can be determined and requested to be retransmitted, a reliable communication environment can be established.

In particular, when a plurality of member servers are included in the same multicast group and the predetermined information is synchronized to distribute the information, the plurality of member servers must be synchronized exactly by maintaining the same state and data. According to the present invention, it is possible to accurately determine whether multicast reception of the plurality of member servers is performed and to request retransmission when some of them are lost, so that the plurality of member servers belonging to the same group can maintain the same state and data.

If member servers included in the same multicast group manage user login / logout information, the member servers receive the login / logout messages received from one member server as multicast messages and maintain the same status. It is possible to distribute the user's login / logout information by means of distribution. When the multicast message transmitted from one member server to other member servers is lost, the other member servers may perform a server sequence of the damaged multicast message. Since the multicast message can be re-requested to the server that transmitted the multicast message, it is possible to prevent an error that may occur because data and states of member servers belonging to the same multicast group do not match.

 In addition, the method of providing a reliable communication of the present invention can be applied to communication between servers of any group including a plurality of servers as well as member servers belonging to the multicast group. In this case, the servers may transmit a general message including predetermined information other than the multicast message to other member servers, and transmit a final notification message at predetermined time intervals to determine whether the message is lost or not. By determining the sequence of lost messages to determine whether the message is lost and requesting retransmission, it is possible to prevent an error due to the lost message and to transmit and receive the message in a reliable communication method between the member servers.

9 is a diagram illustrating an embodiment of providing a reliable communication method between member servers according to the present invention.

Referring to FIG. 9, a first server 901 among member servers according to the present invention transmits message 1, message 2, message 3, and message 4 in order to a second server 902 which is another member server belonging to the same group. . At this time, message 4 may be lost in the transmission process. The second server 902 receives the message 1. message 2. message 3, and stores a first server identifier that transmitted the message and a server sequence for the messages in a server sequence storage.

The first server 901 transmits the message 5 to the second server 902, and the second server 902 receives and stores the message 5. The second server 902 compares the server sequence stored in the server sequence storage unit with the server sequence of the message 5, and when the server sequence of the message 5 is larger than the sum of a predetermined value in the stored server sequence, the stored sequence Transmits to the first server 901 a retransmission request message requesting retransmission of message 4, which is a message corresponding to a server sequence obtained by summing predetermined values.

After receiving the retransmission request message, the first server 901 retrieves message 4 corresponding to the server sequence for the message to be retransmitted from the message buffer and retransmits it to the second server.

The retransmission of such a lost message is applied to all messages received from other member servers belonging to the same group, so that the member server according to the present invention determines whether the message received from other member servers belonging to one group is lost or not. Since retransmission can be requested, the message can be transmitted and received in a reliable communication environment.

10 illustrates another embodiment for providing a reliable communication method between member servers according to the present invention.

Referring to FIG. 10, the first server 1001 and the second server 1002 are member servers belonging to the same group.

Among the member servers according to the present invention, the first server 1001 sequentially transmits message 1, message 2, message 3, and message 4 to second server 1002, which is another member server belonging to the same group. At this time, message 4 may be lost in the transmission process.

Each time the first server 1001 transmits the message, the first server identifier increases the first server sequence held in the server sequence storage unit by a predetermined value and identifies the first server 1001 at predetermined time intervals. And a final sequence notification message including the first server sequence stored in the server sequence storage to the second server 1002.

When the second server 1002 receives the final sequence notification message from the first server 1001, the second server 1002 identifies the stored server sequence by referring to the first server identifier included in the final sequence notification message and includes the final sequence notification message in the final sequence notification message. Retransmission message requesting retransmission of a message corresponding to the server sequence in which the predetermined value is added to the first server 1001 when the first server sequence is greater than or equal to the sum of the predetermined value in the stored server sequence. Send it.

That is, the first server 1001 transmits the last sequence notification message to the second server by including “4”, which is a sequence corresponding to the message 4, and the second server 1002 corresponds to the last received message 3. Since the sequence "3" will be stored, the second server 1002 transmits a retransmission request message requesting retransmission of message 4 to the first server.

The first server 1001 retrieves the message 4 from the message buffer and retransmits it to the second server 1002.

Accordingly, according to the present invention, the first server that has sent the message transmits a final sequence notification message including the first server identifier and the first server sequence to other member servers at regular time intervals, whereby the first server sends the multicast message. After transmitting, even if other messages are not transmitted to other servers for a predetermined period of time, other servers can determine that the message corresponding to the first server sequence is lost and request retransmission.

The present invention has the effect of providing reliable communication by requesting retransmission by determining that the other member server has lost the last message transmitted by one member server belonging to the same group. This effect clearly solves the problems of the prior art described in FIG.

The communication providing method according to the present invention can be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on the media may be those specially designed and constructed for the purposes of the present invention, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical media such as CD-ROMs, DVDs, and magnetic disks, such as floppy disks. Magneto-optical media, and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. The medium may be a transmission medium such as an optical or metal wire, a waveguide, or the like including a carrier wave for transmitting a signal specifying a program command, a data structure, or the like. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

11 is a block diagram showing the configuration of a member server for providing reliable communication according to an embodiment of the present invention. Referring to FIG. 11, according to the present invention, a first member server for providing reliable communication with other member servers belonging to one group includes a server sequence storage unit 1101, a message transmitter 1102, and a server sequence manager. 1103, a message receiver 1104, a server sequence searcher 1104, and a retransmission requester 1105.

The server sequence storage unit 1101 stores a first server sequence corresponding to a first member server and stored server sequences corresponding to each of the other member servers. An embodiment of the server sequence storage unit 1101 has been described with reference to the reference numeral 601 of FIG. 6.

When the message transmitter 1102 transmits a message to the other member servers belonging to the group, the message transmitter 1102 includes the first server identifier for identifying the first member server and the first server sequence in the message.

The server sequence manager 1103 increments the first server sequence held in the server sequence storage unit by a predetermined value every time the message is transmitted. As described above, the predetermined value may be variously set according to the embodiment.

In addition, the message receiving unit 1104 receives a final sequence notification message from a second member server, which is one of other member servers. The final sequence notification message includes a second server identifier of the second member server and a second server sequence corresponding to the second member server.

The sequence retrieval unit 1105 identifies the second stored server sequence corresponding to the second server identifier stored in the server sequence storage unit by referring to the second server identifier included in the final sequence notification message.

The retransmission request unit 1106, when the second server sequence is greater than or equal to the sum of the predetermined value to the second stored server sequence, sends the predetermined value to the second stored server sequence to the second member server. Request retransmission of the message corresponding to the sum of the server sequences.

As described above, the retransmission request unit 1106 of the member server requests the member server to retransmit a message corresponding to a server sequence obtained by adding a predetermined value, thereby determining the lost message and requesting retransmission.

The message transmitter 1102 may also send a final sequence notification message to the other member servers including a first server identifier identifying the first member server at a predetermined time interval and a first server sequence stored in the server sequence storage. Send.

The message transmitter 1102 has an effect of finally confirming the sequence of messages received by the other member servers from the member server by transmitting the final sequence notification message to the other member servers as described above.

In addition, the message receiving unit 1104 receives a second message from a second member server which is one of the other member servers. The second message includes a second server identifier of the second member server and a second server sequence corresponding to the second member server.

The server sequence search unit 1105 identifies a second stored server sequence corresponding to the second server identifier stored in the server sequence storage unit by referring to the second server identifier included in the second message.

The retransmission request unit 1106 adds the predetermined value to the second stored server sequence to the second member server when the second server sequence is larger than the predetermined value added to the second stored server sequence. Resend the message corresponding to one server sequence.

Also, the message receiving unit 1104 may receive a retransmission request message from a second member server which is one of the other member servers. The retransmission request message includes a second server sequence for the message to be retransmitted.

In addition, the message retrieval unit 1107 retrieves the message corresponding to the second server sequence from the message buffer storing the message transmitted from the member server, and the message transmitting unit 1102 transmits the retrieved message to the second member server. Can transmit

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above-described embodiments, which can be variously modified and modified by those skilled in the art to which the present invention pertains. Modifications are possible. Accordingly, the spirit of the present invention should be understood only by the claims set forth below, and all equivalent or equivalent modifications thereof will belong to the scope of the present invention.

The present invention can provide a communication providing method or apparatus that can reliably implement the transmission and reception of messages between servers so that data and states between location servers belonging to the same multicast group can be kept the same.

The present invention also provides a first member server that transmits a multicast message to other member servers among member servers belonging to the same multicast group to transmit a final sequence notification message confirming receipt of the multicast message to the other member servers. Thus, other member servers check for missing multicast messages and, if lost, request retransmission so that member servers belonging to the same multicast group send and receive messages to each other to determine the lost messages and retransmit them. Thus, reliable communication can be provided.

In addition, according to the present invention, the first server transmitting the multicast message transmits a final sequence notification message including the first server identifier and the first server sequence to other member servers at regular time intervals, whereby the first server transmits the multicast message. After transmitting, even if other multicast messages are not transmitted to other servers for a predetermined period of time, other servers can determine that the message corresponding to the first server sequence is lost and request retransmission to provide reliable communication. can do.

In addition, the present invention by determining the sequence of the transmitted message to determine whether the message is lost, re-transmission request received to prevent errors due to the lost message, and send and receive messages in a reliable communication method between member servers belonging to the same group Do it.

In addition, the present invention provides reliable communication by requesting retransmission by determining by the other member server even if the last message transmitted by one member server belonging to the same group is lost.

Claims (14)

A method for providing reliable communication between member servers belonging to the same multicast group, The server sequence storage of the first member server belonging to the multicast group is stored in the first server sequence corresponding to the first member server and each of the other member servers belonging to the same multicast group as the first member server. Maintaining server sequences; When transmitting a multicast message to the other member servers belonging to the multicast group, including the first server identifier and the first server sequence identifying the first member server in the multicast message; Incrementing the first server sequence held in the server sequence storage by a predetermined value each time the multicast message is transmitted; A final sequence notification message from a second member server belonging to the same multicast group as the member server, wherein the final sequence notification message indicates a second server identifier of the second member server and a second server sequence corresponding to the second member server; Including-receiving; Identifying a second stored server sequence corresponding to the second server identifier stored in the server sequence storage unit by referring to a second server identifier included in the final sequence notification message; If the second server sequence is greater than or equal to the sum of the predetermined values in the second stored server sequence, the second member server corresponds to the server sequence in which the predetermined value is added to the second stored server sequence. Requesting retransmission of the multicast message; Receiving a retransmission request message from a second member server belonging to the same multicast group as the first member server, wherein the retransmission request message includes a second server sequence for the multicast message to be retransmitted; And Retrieving a multicast message corresponding to the second server sequence from a message buffer storing the multicast message transmitted from the member server and transmitting the multicast message to the second member server; Reliable communication providing method comprising a. The method of claim 1, The other member server belonging to the same multicast group as the member server, the final sequence notification message including a first server identifier identifying the first member server at a predetermined time interval and a first server sequence stored in the server sequence storage. Sending them Reliable communication providing method comprising a further. The method of claim 1, A second multicast message from a second member server belonging to the same multicast group as the first member server, wherein the second multicast message corresponds to a second server identifier of the second member server and a second member server corresponding to the second member server; Including a 2 server sequence; Identifying a second stored server sequence corresponding to the second server identifier stored in the server sequence storage unit by referring to a second server identifier included in the second multicast message; And When the second server sequence is larger than the sum of the predetermined values in the second stored server sequence, the second member server corresponds to the server sequence in which the predetermined value is added to the second stored server sequence. Resending the Cast Message Reliable communication providing method comprising a further. delete In the method for providing reliable communication between member servers belonging to one group, Maintaining a first server sequence corresponding to the first member server and stored server sequences corresponding to each of the other member servers in a server sequence storage of a first member server belonging to the group; When sending a message to the other member servers belonging to the group, including the first server identifier and the first server sequence identifying the first member server in the message; Incrementing the first server sequence held in the server sequence storage by a predetermined value each time the message is transmitted; Transmitting to the other member servers a final sequence notification message comprising a first server identifier identifying the first member server and a first server sequence stored in the server sequence storage at regular time intervals; Receiving a retransmission request message from a second member server, one of the other member servers, the retransmission request message comprising a second server sequence for the message to be retransmitted; And Retrieving a message corresponding to the second server sequence from a message buffer storing a message transmitted from the member server and transmitting the message to the second member server; Reliable communication providing method comprising a. The method of claim 5, A final sequence notification message from a second member server that is one of the other member servers-the final sequence notification message includes a second server identifier of the second member server and a second server sequence corresponding to the second member server -Receiving; Identifying a second stored server sequence corresponding to the second server identifier stored in the server sequence storage unit by referring to a second server identifier included in the final sequence notification message; And If the second server sequence is greater than or equal to the sum of the predetermined values in the second stored server sequence, the second member server corresponds to the server sequence in which the predetermined value is added to the second stored server sequence. Requesting retransmission of the message Reliable communication providing method comprising a further. The method of claim 5, A second message from a second member server that is one of the other member servers, the second message comprising a second server identifier of the second member server and a second server sequence corresponding to the second member server; Receiving; Identifying a second stored server sequence corresponding to the second server identifier stored in the server sequence storage unit by referring to a second server identifier included in the second message; And A message corresponding to a server sequence obtained by adding the predetermined value to the second stored server sequence to the second member server when the second server sequence is larger than a predetermined value added to the second stored server sequence; Requesting resend of Reliable communication providing method comprising a further. delete A computer-readable recording medium having recorded thereon a program for executing the method of any one of claims 1 to 3. A first member server for providing reliable communication with other member servers belonging to one group, A server sequence storage unit for storing a first server sequence corresponding to the first member server and stored server sequences corresponding to each of the other member servers; A message transmitter configured to transmit a message to the other member servers belonging to the group, the message including a first server identifier identifying the first member server and the first server sequence; A server sequence manager which increases the first server sequence held in the server sequence storage unit by a predetermined value each time the message is transmitted; A final sequence notification message from a second member server that is one of the other member servers-the final sequence notification message includes a second server identifier of the second member server and a second server sequence corresponding to the second member server A message receiving unit receiving a; A server sequence search unit identifying a second stored server sequence corresponding to the second server identifier stored in the server sequence storage unit by referring to a second server identifier included in the final sequence notification message; And If the second server sequence is greater than or equal to the sum of the predetermined values in the second stored server sequence, the second member server corresponds to the server sequence in which the predetermined value is added to the second stored server sequence. Retransmission request unit requesting retransmission of the message Reliable communication providing apparatus comprising a. delete The method of claim 10, The message transmitting unit transmits to the other member servers a final sequence notification message including a first server identifier identifying the first member server and a first server sequence stored in the server sequence storage unit at regular time intervals. Reliable communication providing apparatus. The method of claim 10, A second message from a second member server that is one of the other member servers, the second message comprising a second server identifier of the second member server and a second server sequence corresponding to the second member server; Receiving message receiving unit; A server sequence retrieval unit identifying a second stored server sequence corresponding to the second server identifier stored in the server sequence storage unit by referring to a second server identifier included in the second message; And A message corresponding to a server sequence obtained by adding the predetermined value to the second stored server sequence to the second member server when the second server sequence is larger than a predetermined value added to the second stored server sequence; Retransmission request unit requesting retransmission Reliable communication providing apparatus comprising a. The method of claim 10, A message receiving unit for receiving a retransmission request message from a second member server which is one of the other member servers, the retransmission request message including a second server sequence for a message to be retransmitted; And A message retrieval unit for retrieving a message corresponding to the second server sequence from a message buffer storing a message transmitted from the member server More, And the message transmitting unit transmits the retrieved message to the second member server.

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