Patent Application
20190296980
This application claims priority from Japanese Patent Application No. 2018-052009 filed Mar. 20, 2018. The entire content of the priority application is incorporated herein by reference.
This disclosure relates to a storage medium storing a communication program, a communication method, and a communication system.
Various communication methods have been suggested to perform a teleconference between a server apparatus and a terminal apparatus connected through a network. A multipoint conference system is suggested. The multipoint conference system includes a plurality of MCUs, a resource management server, and a plurality of terminals. The respective MCUs and the plurality of terminals are connected to networks for the respective areas (hereinafter referred to as “area network”). The respective MCUs control a multipoint conference (hereinafter simply referred to as “conference”) by transferring packets transmitted and received among the plurality of terminals. The resource management server performs resource management on each of the plurality of MCUs. For example, when a first MCU controlling a specific conference has insufficient resources, request information is transmitted to the resource management server. Based on the request information, the resource management server extracts a second MCU as a substitute and notifies the second MCU. The second MCU transmits the address of the second MCU to a plurality of terminals participating in the conference controlled by the first MCU and switches a connection destination to continue the conference.
According to one aspect, this specification discloses a non-transitory computer-readable storage medium storing a communication program executable on a computer of a first server apparatus in a plurality of server apparatuses configured to control communication among a plurality of terminal apparatuses. Each of the plurality of server apparatuses has a memory storing a management table specifying a handling server apparatus configured to perform communication with the plurality of terminal apparatuses. Each of the plurality of server apparatuses is configured to identify a terminal apparatus to perform communication with based on the management table and to transfer data to the identified terminal apparatus. The communication program causes, when executed, the first server apparatus to perform operations including: transmitting, to a first terminal apparatus, a connection request for requesting connection between the first terminal apparatus and a second server apparatus different from the first server apparatus; after the first terminal apparatus and the second server apparatus are connected based on the connection request, receiving a connection completion notification transmitted from the first terminal apparatus; in response to receiving the connection completion notification, transmitting a first update request to the second server apparatus, the first update request being for updating the handling server apparatus of the first terminal apparatus specified in a second management table from the first server apparatus to the second server apparatus, the second management table being stored in a second memory of the second server apparatus; after the second management table is updated based on the first update request, receiving a first update completion notification transmitted from the second server apparatus; in response to receiving the first update completion notification, transmitting a second update request to a third server apparatus, the second update request being for updating the handling server apparatus of the first terminal apparatus specified in a third management table from the first server apparatus to the second server apparatus, the third management table being stored in a third memory of a third server apparatus different from the first server apparatus and the second server apparatus; after the third management table is updated based on the second update request, receiving a second update completion notification transmitted from the third server apparatus; and in response to receiving the second update completion notification, updating the handling server apparatus of the first terminal apparatus specified in a first management table from the first server apparatus to the second server apparatus, the first management table being stored in a first memory of the first server apparatus, thereby changing the handling server apparatus of the first terminal apparatus from the first server apparatus to the second server apparatus.
According to another aspect, this specification also discloses a communication method performed by a plurality of server apparatuses configured to control communication among a plurality of terminal apparatuses. Each of the plurality of server apparatuses has a memory storing a management table specifying a handling server apparatus configured to perform communication with the plurality of terminal apparatuses. Each of the plurality of server apparatuses is configured to identify a terminal apparatus to perform communication with based on the management table and to transfer data to the identified terminal apparatus. The method including: transmitting, from a first server apparatus to a first terminal apparatus, a connection request for requesting connection between the first terminal apparatus and a second server apparatus different from the first server apparatus; after the first terminal apparatus and the second server apparatus are connected based on the connection request, receiving, by the first server apparatus, a connection completion notification transmitted from the first terminal apparatus; in response to receiving the connection completion notification, transmitting a first update request from the first server apparatus to the second server apparatus, the first update request being for updating the handling server apparatus of the first terminal apparatus specified in a second management table from the first server apparatus to the second server apparatus, the second management table being stored in a second memory of the second server apparatus; after the second management table is updated based on the first update request, receiving, by the first server apparatus, a first update completion notification transmitted from the second server apparatus; in response to receiving the first update completion notification, transmitting a second update request from the first server apparatus to a third server apparatus, the second update request being for updating the handling server apparatus of the first terminal apparatus specified in a third management table from the first server apparatus to the second server apparatus, the third management table being stored in a third memory of a third server apparatus different from the first server apparatus and the second server apparatus; after the third management table is updated based on the second update request, receiving, by the first server apparatus, a second update completion notification transmitted from the third server apparatus; and in response to receiving the second update completion notification, updating the handling server apparatus of the first terminal apparatus specified in a first management table from the first server apparatus to the second server apparatus, the first management table being stored in a first memory of the first server apparatus, thereby changing the handling server apparatus of the first terminal apparatus from the first server apparatus to the second server apparatus.
According to still another aspect, this specification also discloses a communication system. The communication system includes a plurality of terminal apparatuses and a plurality of server apparatuses. The plurality of server apparatuses is configured to control communication among the plurality of terminal apparatuses. Each of the plurality of server apparatuses has a memory storing a management table specifying a handling server apparatus configured to perform communication with the plurality of terminal apparatuses. Each of the plurality of server apparatuses is configured to identify a terminal apparatus to perform communication with based on the management table and to transfer data to the identified terminal apparatus. A first server apparatus of the plurality of server apparatuses includes: a controller; and a first memory storing instructions, the instructions, when executed by the controller, causing the first server apparatus to perform: transmitting, to a first terminal apparatus, a connection request for requesting connection between the first terminal apparatus and a second server apparatus different from the first server apparatus; after the first terminal apparatus and the second server apparatus are connected based on the connection request, receiving a connection completion notification transmitted from the first terminal apparatus; in response to receiving the connection completion notification, transmitting a first update request to the second server apparatus, the first update request being for updating the handling server apparatus of the first terminal apparatus specified in a second management table from the first server apparatus to the second server apparatus, the second management table being stored in a second memory of the second server apparatus; after the second management table is updated based on the first update request, receiving a first update completion notification transmitted from the second server apparatus; in response to receiving the first update completion notification, transmitting a second update request to a third server apparatus, the second update request being for updating the handling server apparatus of the first terminal apparatus specified in a third management table from the first server apparatus to the second server apparatus, the third management table being stored in a third memory of a third server apparatus different from the first server apparatus and the second server apparatus; after the third management table is updated based on the second update request, receiving a second update completion notification transmitted from the third server apparatus; and in response to receiving the second update completion notification, updating the handling server apparatus of the first terminal apparatus specified in a first management table from the first server apparatus to the second server apparatus, the first management table being stored in the first memory of the first server apparatus, thereby changing the handling server apparatus of the first terminal apparatus from the first server apparatus to the second server apparatus. The first terminal apparatus includes: a terminal controller; and a terminal memory storing instructions, the instructions, when executed by the controller, causing the first terminal apparatus to perform: in response to receiving the connection request transmitted from the first server apparatus, connecting with the second server apparatus; and after connecting with the second server apparatus, transmitting the connection completion notification to the first server apparatus.
Embodiments in accordance with this disclosure will be described in detail with reference to the following figures wherein:
In order to allow the conference to proceed, a plurality of packets transmitted from a transmission-side terminal are preferably received by a reception-side terminal in a sequence of the transmission. However, when the MCU controlling the conference is switched by the above method, packets are transferred by a plurality of MCUs at a switching stage, which may prevent the reception-side terminal from receiving the plurality of packets in the sequence of the transmission. Furthermore, in the case of the above multipoint conference system, the MCU must transmit a query to the resource management server in order to switch the conference controlled by the MCU to another MCU, which may result in complicated processing.
An example of an object of this disclosure is to provide a storage medium storing a communication program, a communication method, and a communication system by which processing is easily performed to switch a server apparatus controlling a conference to another server apparatus and a plurality of packets is received by a reception-side terminal during switching in a sequence of the transmission.
<Outline of the Communication System 1>
With reference to
The terminal apparatus C conducts a teleconference by performing communication with another terminal apparatus C through the server apparatus S. When a teleconference is held, in the communication system 1, a server apparatus S is allocated to each of the terminal apparatuses C participating in the teleconference (hereinafter referred to as “handling server apparatus”). Video data and audio data (hereinafter referred to as “conference data”) for the teleconference are transferred through the handling server apparatus allocated to the terminal apparatus C. In this case, the terminal apparatus C and the handling server apparatus allocated to the terminal apparatus C have therebetween no server apparatus S other than the handling server apparatus. The video data is data regarding video taken by a camera of the terminal apparatus C for example. The audio data is data regarding audio collected by a microphone of the terminal apparatus C for example.
For example,
When the server apparatus S receives the conference data from the terminal apparatus C and transfers the data or when the server apparatus S receives the conference data from another server apparatus S and transfers the data to the terminal apparatus C, the server apparatus S transfers at least part of a video key frame, an audio key frame, video data, and audio data (hereinafter referred to as “particular data”) specified based on setting information 16 described later (see
<Electrical Configuration>
The terminal apparatus C has a CPU 21, a memory 22, an input interface 23, an output interface 24, a communication interface 25, and a reader 26. The CPU 21 is responsible for the entirety of the control by the terminal apparatus C. The memory 22 stores various programs executed by the CPU 21. The memory 22 stores therein the ID of the handling server apparatus (which will be referred to as a “handling server ID”). The memory 22 includes a plurality of transmission buffers and a plurality of reception buffers to store conference data in a FIFO format. For example, when the CPU 21 transmits the conference data to another terminal apparatus C, the CPU 21 stores the conference data sequentially in each of the plurality of transmission buffers. Then, the CPU 21 extracts the conference data stored in each of the plurality of transmission buffers in a sequence in which the data is stored in the plurality of transmission buffers, and transmits the data. When the CPU 21 receives the conference data transmitted from the server apparatus S, the CPU 21 sequentially stores the conference data in a plurality of reception buffers. Then, the CPU 21 extracts and processes the conference data stored in the plurality of reception buffers in a sequence in which the data is stored in the plurality of reception buffers.
The input interface 23 includes a camera, a microphone, a keyboard, and a mouse for example. The output interface 24 includes an LCD and a speaker for example. The communication interface 25 is an interface element to provide communication through the network N. The reader 26 reads information stored in a storage medium 26A such as a semiconductor memory or an optical disc. The CPU 21 controls the reader 26 to read a program stored in the storage medium 26A and stores the program in the memory 22. The program stored in the memory 22 may also be downloaded from another server connected to the network N for example.
The server apparatus S has a CPU 11, a memory 12, a communication interface 13, and a reader 14. The CPU 11 is responsible for the entirety of the control by the server apparatus S. The memory 12 stores therein various programs executed by the CPU 11, a management table 15 described later, and the setting information 16. The memory 12 includes a plurality of transfer buffers to store conference data in a FIFO (First In, First Out) format. The FIFO format is also called as a First In, First Out format according to which data is extracted from an array in a sequence in which the data are stored in the array. For example, when the CPU 11 receives conference data transmitted from another server apparatus S or terminal apparatus C, the CPU 11 sequentially stores the conference data in a plurality of transfer buffers. Then, the CPU 11 extracts the conference data stored in each of the plurality of transfer buffers in a sequence in which the data are stored in the plurality of transfer buffers and transmits the data to transfer the data to other server apparatus S or terminal apparatus C.
The communication interface 13 is an interface element to provide communication through the network N. The reader 14 reads information stored in a storage medium 14A such as a semiconductor memory or an optical disc. The CPU 11 controls the reader 14 to read a program stored in the storage medium 14A and stores the data in the memory 12. The program stored in the memory 12 may also be downloaded from another server connected to the network N, for example.
<Management Table 15>
The management table 15 is stored in the memory 12 of each server apparatus S. The management table 15 specifies a handling server apparatus for each terminal apparatus C. The IDs of the terminal apparatuses C and the handling server apparatuses are associated and stored in the management table 15. In the state shown in
The CPU 11 of the server apparatus S refers to the management table 15 stored in the memory 12, and identifies the terminal apparatus C that the server apparatus S itself handles. When the CPU 11 receives, from another server apparatus S, conference data addressed to the identified terminal apparatus C, the CPU 11 transfers the received conference data to the terminal apparatus C without passing through other server apparatuses S. When the CPU 11 receives, from the terminal apparatus C that the CPU 11 handles, the conference data addressed to another terminal apparatus C, the CPU 11 refers to the management table 15 stored in the memory 12 to identify another server apparatus S that handles the another terminal apparatus C. The CPU 11 transfers the received conference data to the identified server apparatus S.
In the following description, it is assumed that the CPUs 21 of the terminal apparatuses C1, C2, C3, and C4 are referred to as “CPU 211”, “CPU 212”, “CPU 213”, and “CPU 214”, respectively. It is assumed that the CPUs 11 of the server apparatuses S1, S2, S3, and S4 are referred to as “CPU 111”, “CPU 112”, “CPU 113”, and “CPU 114”, respectively. It is assumed that the memories 12 of the server apparatuses S1, S2, S3, and S4 are referred to as “memory 121”, “memory 122”, “memory 123”, and “memory 124”, respectively. It is assumed that the management tables 15 stored in the respective memories 121, 122, 123, and 124 are referred to as “management table 151”, “management table 152”, “management table 153”, and “management table 154”, respectively.
<Setting Information 16>
The setting information 16 is stored in the memory 12 of each server apparatus S.
The setting information 16 is associated with flag information. The flag information shows whether the setting information 16 is changed in response to setting change data transmitted from the master server apparatus MS or the terminal apparatus C. The setting information 16 prior to the change is associated with flag information “0” showing that the setting information 16 is not changed. When the setting information 16 is changed in response to the setting change data, the setting information 16 is associated with flag information “1” showing that the setting information 16 is changed.
<Communication Sequence>
The following section will describe a communication sequence used when the handling server apparatus of the terminal apparatus C1 is switched from the server apparatus S1 to the server apparatus S2. As shown in
The CPU 11 of the server apparatus S reads and executes a program stored in the memory 12 to thereby execute processing corresponding to the communication sequence. The CPU 11 executes transfer processing shown below in parallel with the processing based on the following communication sequence. When the CPU 11 receives conference data, the CPU 11 sequentially stores the received conference data in a plurality of transfer buffers of the memory 12. It is assumed in the following description that the CPU 11 sequentially extracts the conference data stored in the plurality of transfer buffers in a FIFO format unless otherwise specified. The CPU 11 specifies a transmission destination for the extracted conference data (another server apparatus S or terminal apparatus C) based on the management table 15 stored in the memory 12. Furthermore, the CPU 11 extracts, from the extracted conference data, the particular data specified by the setting information 16 stored in the memory 12. Based on the specified transmission destination, the CPU 11 transmits the extracted particular data.
The CPU 21 of the terminal apparatus C reads and executes the program stored in the memory 22 to thereby execute processing corresponding to the communication sequence. The CPU 21 executes, in parallel with the processing based on the following communication sequence, a transmission processing and a reception processing shown below. In the transmission processing, when the CPU 21 acquires the conference data through a camera and a microphone of the input interface 23, the acquired conference data is stored in a plurality of transmission buffers of the memory 22. The CPU 21 sequentially extracts the conference data stored in the plurality of transmission buffers in a FIFO format, unless otherwise specified below. Furthermore, the CPU 21 specifies a handling server apparatus based on the handling server ID stored in the memory 22. The CPU 21 transmits, to the specified handling server apparatus, the conference data sequentially extracted from the plurality of transmission buffers. In the reception processing, the CPU 21 receives the particular data transmitted from the handling server apparatus and sequentially stores the data in a plurality of reception buffers. The CPU 21 extracts and processes the particular data stored in each of the plurality of reception buffers in a sequence in which the data are stored in the plurality of reception buffers. Specifically, the CPU 21 controls the LCD of the output interface 24 to display a video image based on the extracted video data. The CPU 21 controls a speaker of the output interface 24 to output audio based on the extracted audio data.
<First Phase>
With reference to
<Second Phase>
With reference to
The CPU 111 of the server apparatus S1 transmits, to the terminal apparatus C1, preparation request data requesting preparation for switching the handling server apparatus of the terminal apparatus C1 from the server apparatus S1 to the server apparatus S2 (T117). The CPU 211 of the terminal apparatus C1 receives the preparation request data (T119). The CPU 211 transmits, to the server apparatus S1, an ACK (acknowledgement response, or Acknowledgement) notifying that the preparation request data is received (T121). The CPU 111 of the server apparatus S1 receives the ACK (T123).
After the transmission of the ACK (T121) is completed, the CPU 211 of the terminal apparatus C1 suspends transmission processing and reception processing executed in parallel with the communication sequence until switching completion response data is transmitted in T305 described later (see
At the time of the completion of the second phase, each of the management table 151 of the server apparatus S1 and the management table 152 of the server apparatus S2 are not updated and are maintained in the state shown in
<Third Phase>
With reference to
The CPU 112 of the server apparatus S2 receives the first update request data (T203). The CPU 112 performs flush transmission of the conference data when a plurality of transfer buffers provided in the memory 122 stores one or more conference data addressed to the server apparatus S1 that have been received during the period (P201) until the first update request data is received (T203) and that are not yet transmitted by the transfer processing (T205). Specifically, the following processing is performed. The CPU 112 sequentially extracts, in a FIFO format, the particular data specified by the setting information 16 stored in the memory 122 from among one or more conference data stored in the plurality of transfer buffers, and transmits the extracted data to the server apparatus S1. The CPU 112 repeats the processing to transmit the particular data to the server apparatus S1 until there is no more conference data addressed to the server apparatus S1 stored in the plurality of transfer buffers. The CPU 111 of the server apparatus S1 receives the particular data transmitted from the server apparatus S2 (T207).
After the completion of the flush transmission, the CPU 112 of the server apparatus S2 changes and updates the management table 152 stored in the memory 122 in such a manner that the ID “S1” of the server apparatus S1 associated with the ID “C1” of the terminal apparatus C1 is changed to the ID “S2” of the server apparatus S2 (U209). Based on the updated management table 152, the CPU 112 resumes the processing to transfer the conference data. For example, when the CPU 112 receives the conference data addressed to the terminal apparatus C1, the CPU 112 transmits the received conference data to the terminal apparatus C1 and does not transfer the data to the server apparatus S1. The CPU 112 transmits, to the server apparatus S1, a first update completion notification data showing that the update of the management table 152 is completed (T209). The CPU 111 of the server apparatus S1 receives the first update completion notification data (T211).
The CPU 111 of the server apparatus S1 determines whether the communication system 1 includes therein the server apparatus S other than the server apparatus S1 that is the handling server apparatus of the terminal apparatus C1 prior to the switching and the server apparatus S2 that is the handling server apparatus of the terminal apparatus C1 after the switching (J001). In the embodiment, the CPU 111 determines that the communication system 1 includes therein the plurality of server apparatuses S (the server apparatuses S3 and S4) other than the server apparatuses S1 and S2.
The CPU 111 transmits, to the server apparatus S3, a second update request data to change the handling server apparatus of the terminal apparatus C1 specified in the management table 153 (see
The CPU 113 of the server apparatus S3 receives the second update request data (T223). The CPU 113 performs flush transmission of the conference data when a plurality of transfer buffers provided in the memory 123 stores one or more conference data addressed to the server apparatus S1 that are received during the period (P203) until the second update request data is received (T223) and that are not yet transmitted by the transfer processing (T225). Specifically, the following processing is performed. The CPU 113 sequentially extracts, in a FIFO format, the particular data specified by the setting information 16 stored in the memory 123 from among one or more conference data stored in the plurality of transfer buffers, and transmits the extracted data to the server apparatus S1. The CPU 113 repeats the processing to transmit the conference data to the server apparatus S1 until there is no more conference data addressed to the server apparatus S1 stored in the plurality of transfer buffers. The CPU 111 of the server apparatus S1 receives the conference data transmitted from the server apparatus S3 (T227). The same processing as the one described above is also performed in the CPU 114 of the server apparatus S4 having received the second update request data.
After the completion of the flush transmission, the CPU 113 of the server apparatus S3 changes and updates the management table 153 stored in the memory 123 in such a manner that the ID “S1” of the server apparatus S1 associated with the ID “C1” of the terminal apparatus C1 is changed to the ID “S2” of the server apparatus S2 (U229). Based on the updated management table 153, the CPU 113 resumes the processing to transfer the conference data. For example, when the CPU 113 receives the conference data addressed to the terminal apparatus C1, the CPU 113 transfers the received conference data to the server apparatus S2 and does not transfer the data to the server apparatus S1. The CPU 113 transmits, to the server apparatus S1, the second update completion notification data showing that the update of the management table 153 is completed (T229). The same processing as the one described above is also performed in the CPU 114 of the server apparatus S4 having received the second update request data.
The CPU 111 of the server apparatus S1 receives the second update completion notification data (T231). The CPU 111 determines whether the CPU 111 has received the second update completion notification data from all of the server apparatuses S3 and S4 to which the second update request data has been transmitted in T221 (J003). When the CPU 111 determines that the CPU 111 does not receive the second update completion notification data from at least any one of the server apparatuses S3 and S4, the CPU 111 completes the communication sequence in the third phase after waiting for a particular period.
When the CPU 111 determines that the second update completion notification data is received from all of the server apparatuses S3 and S4, the CPU 111 executes the following processing. Here, the CPU 111 suspends the transfer processing during the period after the first update request data is transmitted to the server apparatus S1 in T201 and before the second update completion notification data is received in T231. Thus, when the conference data addressed to the terminal apparatus C1 is received during this period, the conference data is stored in the plurality of transfer buffers provided in the memory 121 (V201). The CPU 111 performs flush transmission of the conference data when the plurality of transfer buffers stores one or more conference data addressed to the server apparatus S1 (T233). Specifically, the following processing is performed. The CPU 111 sequentially extracts, in a FIFO format, the particular data specified by the setting information 16 stored in the memory 121 from among one or more conference data stored in the plurality of transfer buffers, and transmits the extracted data to the terminal apparatus C1. The CPU 112 repeats the processing to transmit the conference data to the terminal apparatus C1 until there is no more conference data addressed to the terminal apparatus C1 stored in the plurality of transfer buffers. The CPU 211 of the terminal apparatus C1 receives the conference data transmitted from the server apparatus S1 (T235). It is noted that, during the period from T121 (see
After the completion of the flush transmission, the CPU 111 of the server apparatus S1 changes and updates the management table 151 stored in the memory 121 in such a manner that the ID “S1” of the server apparatus S1 associated with the ID “C1” of the terminal apparatus C1 is changed to the ID “S2” of the server apparatus S2 (U233). Based on the updated management table 151, the CPU 111 resumes the processing to transfer the conference data. For example, when the CPU 111 receives the conference data addressed to the terminal apparatus C1, the CPU 111 transfers the received conference data to the server apparatus S2 and does not transfer the data to the terminal apparatus C1.
When the communication system 1 includes only the server apparatuses S1 and S2 for example, the CPU 111 determines, in the processing of J001, that the communication system 1 does not include therein the server apparatus S other than the server apparatuses S1 and S2. In this case, the CPU 111 does not perform T221, T227, T231, and J003. The CPU 111 performs the flush transmission as required (T233). Thereafter, the CPU 111 updates the management table 151 stored in the memory 121 (U233). Based on the updated management table 151, the CPU 111 resumes the processing to transfer the conference data.
<Fourth Phase>
With reference to
The CPU 111 of the server apparatus S1 performs the synchronization processing as described below. The CPU 111 transmits, to the server apparatus S2, the setting information 16 and flag information stored in the memory 121. The CPU 111 receives the setting information 16 and flag information transmitted from the server apparatus S2. The CPU 111 refers to flag information associated with the received setting information 16 and to flag information associated with the setting information 16 stored in the memory 121, and executes any of the processing in (1) to (3) below.
(1) When both setting information 16 are associated with flag information “0” showing that the contents are not changed, the CPU 111 determines that the setting information 16 stored in the memory 121 can be used as it is.
(2) When one setting information 16 is associated with flag information “1” showing that the contents are changed, the CPU 111 uses the setting information 16 associated with the flag information “1” to update the setting information 16 stored in the memory 121. Specifically, when the received setting information 16 is associated with the flag information “1”, the CPU 111 updates the setting information 16 by storing the received setting information 16 in the memory 121. On the other hand, when the setting information 16 stored in the memory 121 is associated with the flag information “1”, the CPU 111 determines that this setting information 16 can be used as it is.
(3) When both flag information are associated with the flag information “1” showing that the contents are changed, the CPU 111 determines that the setting information 16 stored in the memory 121 can be used as it is.
The CPU 112 of the server apparatus S2 executes the synchronization processing as described below. The CPU 112 transmits, to the server apparatus S1, the setting information 16 and flag information stored in the memory 122. The CPU 112 receives the setting information 16 and flag information transmitted from the server apparatus S1. The CPU 112 refers to flag information associated with the received setting information 16 and to flag information associated with the setting information 16 stored in the memory 122, and executes the same processing as in (1) and (2) above or the processing in (4) below.
(4) When both flag information is associated with the flag information “1” showing that the contents are changed, the CPU 112 uses the setting information 16 received from the server apparatus S1 for conference data that are transmitted and received between the CPU 112 and the terminal apparatus C1 through the server apparatus S1. On the other hand, the CPU 112 uses the setting information 16 stored in the memory 122 for conference data transmitted and received between the CPU 112 and the terminal apparatus C1.
After the execution of the synchronization processing by Y001, the CPU 111 of the server apparatus S1 transmits, to the terminal apparatus C1, switching completion notification data notifying that the preparation to switch the handling server apparatus of the terminal apparatus C1 from the server apparatus S1 to the server apparatus S2 is completed (T301). The CPU 211 of the terminal apparatus C1 receives the switching completion notification data (T303). The CPU 211 transmits, to the server apparatus S1, switching completion response data in response to the switching completion notification data (T305). The CPU 111 of the server apparatus S1 receives the switching completion response data (T307).
After the switching completion response data is transmitted to the server apparatus S1 in T305, the CPU 211 of the terminal apparatus C1 changes the handling server ID stored in the memory 221 from the ID “S1” of the server apparatus S1 to the ID “S2” of the server apparatus S2 (U305).
The CPU 211 suspends the transmission processing during the period after the ACK is transmitted from the CPU 211 to the server apparatus S1 in T121 (see
The CPU 211 also suspends the reception processing during the period after the ACK is transmitted from the CPU 211 to the server apparatus S1 in T121 (see
The CPU 211 of the terminal apparatus C1 transmits, to the server apparatus S1, a disconnection request to disconnect the connection with the server apparatus S1. The CPU 111 of the server apparatus S1 receives the disconnection request and disconnects the connection with the terminal apparatus C1 (T313, T315).
First, the server apparatus S1 changes the handling server apparatus of the terminal apparatus C1 in the management table 152 of the server apparatus S2 from the server apparatus S1 to the server apparatus S2 (T201). Next, the server apparatus S1 changes the handling server apparatus of the terminal apparatus C1 in the management tables 153 and 154 of the server apparatuses S3 and S4 from the server apparatus S1 to the server apparatus S2 (T221). Thereafter, the server apparatus S1 changes the handling server apparatus of the terminal apparatus C1 in the management table 151 of the server apparatus S1 from the server apparatus S1 to the server apparatus S2 (U233). That is, after the update of all of the management tables 152, 153, and 154 of other server apparatuses S2, S3, and S4 is completed, the management table 151 of the server apparatus S1 is updated. As a result, during the switching of the management table 15, the communication system 1 can suppress particular data from being transmitted from a plurality of server apparatuses S to the terminal apparatus C. Thus, for example, the sequence of a plurality of particular data received in the terminal apparatus C is maintained even if a plurality of data transmitted and received from the terminal apparatuses C is not attached with information showing the sequence of data. Furthermore, even when a plurality of data transmitted and received between the terminal apparatuses C is attached with information showing the sequence of data, there is a possibility that the sequence of the transmission cannot be maintained when the data is thinned (that is, partially omitted). However, even in such a case, the server apparatus S1 in the embodiment maintains the sequence of a plurality of particular data received in the terminal apparatus C.
In the communication system 1, the server apparatuses S store the management tables 15 in the memories 12, respectively. Thus, for example, each server apparatus S need not transmit a query to the main server apparatus, or the main server need not be stopped during the update of the management table 15 such as when only a specific main server apparatus stores the management table 15 therein. Thus, the server apparatus S easily performs processing to switch the handling server apparatus of the terminal apparatus C to another server apparatus.
The server apparatus S1 switches the handling server apparatus of the terminal apparatus C1 in the management table 151 from the server apparatus S1 to the server apparatus S2 and subsequently disconnects the connection with the terminal apparatus C1 (T313, T315). In this case, the server apparatus S1 reliably switches the handling server apparatus of the terminal apparatus C1 from the server apparatus S1 to the server apparatus S2.
When the server apparatus S1 determines that the communication system 1 includes a plurality of server apparatuses S3 and S4 other than the server apparatuses S1 and S2 (J001), the server apparatus S1 transmits the second update request data to the server apparatuses S3 and S4 (T221). In response to determining that the second update completion notification data is received from all of the server apparatuses S3 and S4 (J003), the server apparatus S1 updates the management table 151 (U233). In this case, the server apparatus S1 updates the management table 151 after the management tables 153 and 154 are updated in all of the server apparatuses S3 and S4 other than the server apparatuses S1 and S2. Thus, the server apparatus S1 reliably maintains the sequence of a plurality of data received by the terminal apparatus C during the switching of the handling server apparatus.
During the period after the first update request data is transmitted from the server apparatus S1 (T201) and before the second update completion notification data is received (T231), the management tables 152 to 154 of the server apparatuses S2 to S4 are updated. Thus, there is a possibility that conference data is transmitted from the server apparatus S2 to the terminal apparatus C1 during this period. When conference data is further transmitted from the server apparatus S1 to the terminal apparatus C1, the sequence of conference data received by the terminal apparatus C1 may be changed. To prevent this, the server apparatus S1 suspends the transfer processing that is executed in parallel with the communication sequence performed in the period from T201 to T231 (V201). During this period, when the server apparatus S1 receives conference data addressed to the terminal apparatus C1, the server apparatus S1 sequentially stores the conference data in a plurality of transfer buffers provided in the memory 121. On the other hand, the server apparatus S1 does not sequentially extract the conference data stored in the plurality of transfer buffers and does not transmit the data to the terminal apparatus C1 (V201). When, after T231, a plurality of transfer buffers provided in the memory 122 stores one or more conference data addressed to the terminal apparatus C1, the CPU 111 performs flush transmission of the conference data (T233). As a result, the server apparatus S1 reliably maintains the sequence of conference data received in the terminal apparatus C1.
In the transfer processing executed by the server apparatus S, particular data specified by the setting information 16 is extracted from the conference data and is transmitted. After the management tables 151 and 152 are updated, the server apparatuses S1 and S2 execute the synchronization processing to synchronize the setting information 16 (Y001). After the setting information 16 is synchronized with the server apparatus S2, the server apparatus S1 disconnects the link connection with the terminal apparatus C1. Thus, after the particular data is transferred to the terminal apparatus C1 based on the setting information 16 common in the server apparatuses S1 and S2, the server apparatus S1 disconnects the link connection to thereby reliably change the handling server apparatus to the server apparatus S2. The setting information 16 specifies at least whether audio data is necessary. In this case, when audio data for example is unnecessary, the server apparatus S excludes the audio data from the setting information 16 to thereby streamline conference data transmitted and received among the terminal apparatuses C to suppress a situation where unnecessary conference data causes large traffic in the network N.
The server apparatus S1 transmits, to the terminal apparatus C1, preparation request data to switch the handling server apparatus of the terminal apparatus C1 (T117). After the link connection with the server apparatus S2 is established, the terminal apparatus C1 transmits the ACK to the server apparatus S1 (T121). Upon receiving the ACK transmitted from the terminal apparatus C1 (T123), the server apparatus S1 transmits the first update request data to the server apparatus S2 (T201). In this case, the server apparatus S1 appropriately determines that the link connection is established between the server apparatus S2 and the terminal apparatus C1, and transmits the first update request data to the server apparatus S2 to update the management table 152.
When the communication system 1 includes only the server apparatuses S1 and S2, the server apparatus S1 does not execute T221, T227, T231, and J003 because the communication system 1 does not include the server apparatus S other than the server apparatuses S1 and S2 (J001), and the server apparatus S1 updates the management table 151 (U233). In this case, the server apparatus S1 quickly updates its management table 151 after the management table 152 of the server apparatus S2 is updated.
During the period after the first update request data is transmitted from the server apparatus S1 (T201) and before the second update completion notification data is received (T231), the management tables 152 to 154 of the server apparatuses S2 to S4 are updated. During this period, the update state of the management table 15 is unstable. Thus, it is preferable for the terminal apparatus C1 not to transmit conference data during this period. To achieve this, during the period after the ACK is transmitted to the server apparatus S1 in T121 and before the switching completion response data is transmitted to the server apparatus S1 in T305, the terminal apparatus C1 suspends the transmission processing (V301). After T305, the terminal apparatus C1 performs flush transmission of the conference data stored in a plurality of transmission buffers to the server apparatus S2 (T309). This consequently allows the terminal apparatus C1 to suppress the transmission of the conference data during the switching of the management table 15 in the server apparatus S and to resume, after the completion of the switching of the management table 15, the transmission of conference data to the server apparatus S2 as a new handling server apparatus. In this case, the sequence of the conference data transmitted from the terminal apparatus C1 is reliably maintained when the conference data is received by other terminal apparatuses C2 to C4.
<Modifications>
While the disclosure has been described in detail with reference to the above aspects thereof, it would be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the claims.
For example, in the second phase, in response to receiving, from the master server apparatus MS, the switching instruction data to switch the handling server apparatus of the terminal apparatus C1 from the server apparatus S1 to the server apparatus S2 (T103), the CPU 111 of the server apparatus S1 transmits connection request data to the terminal apparatus C1 (T105). In contrast, the CPU 111 may transmit the connection request data to the server apparatus S2 in response to detecting an increase in its own processing load. In this case, permission/denial request data in the first phase may also be transmitted from the server apparatus S1 to the server apparatus S2. In this case, the communication system 1 may not include therein the master server apparatus MS.
After the CPU 211 of the terminal apparatus C1 changes the handling server ID stored in the memory 221 from “S1” to “S2” (U305), the CPU 211 transmits, to the server apparatus S1, a disconnection request to disconnect the connection with the server apparatus S1. The CPU 111 of the server apparatus S1 receives the disconnection request and disconnects the connection with the terminal apparatus C1 (T313, T315). In contrast, the CPU 211 of the terminal apparatus C1 itself may disconnect the connection with the server apparatus S1 after the handling server ID is updated. In this case, the CPU 211 may not transmit the disconnection request to the server apparatus S1.
When the second update request data is transmitted to all of the server apparatuses S3 and S4 other than the server apparatuses S1 and S2 (T221), the CPU 111 of the server apparatus S1 may simultaneously transmit a plurality of the second update request data by multicast communication. On the other hand, the CPU 111 may firstly transmit the second update request data to the server apparatus S3 and, after receiving the second update completion notification (T231), next transmit the second update request data to the server apparatus S4.
During the period after the first update request data is transmitted (T201) and before the second update completion notification data is received (T231), the CPU 111 of the server apparatus S1 suspends the transfer processing executed in parallel with the communication sequence (V201). Conference data addressed to the terminal apparatus C1 received during this period is sequentially stored in a plurality of transfer buffers and is not transmitted to the terminal apparatus C1 (V201). In contrast, the CPU 111 may discard the conference data addressed to the terminal apparatus C1 received during the period from T201 to T231 and transmit a NACK (Negative ACKnowledge) to the transmission source to request retransmission. After T231, when the CPU 111 receives the retransmitted conference data, the CPU 111 may transfer the data to the terminal apparatus C1.
After the update of the management tables 151 and 152, the server apparatuses S1 and S2 execute the synchronization processing in order to synchronize the setting information 16 at the start of the fourth phase (Y001). However, the timing at which the synchronization processing is executed is not limited to the start of the fourth phase. For example, the synchronization processing may be executed at any time in the first phase to the third phase. The setting information 16 may not be stored in the memory 12. The CPU 11 of the server apparatus S may execute the transfer processing for all of the received conference data. In this case, the synchronization processing may not be executed.
Data specified by the setting information 16 is not limited to that of the above embodiment. For example, the setting information may be such data that specifies only whether video data is necessary or whether audio data is necessary or such data that specifies only whether audio data is necessary. The setting information 16 also may specify various types of information for the setting of teleconference (e.g., video resolution and compression ratio, or audio compression ratio).
For example, as in the setting information 16A shown in
When the CPU 111 of the server apparatus S1 receives the ACK (T123) in response to the preparation request data (T117) transmitted to the terminal apparatus C1, the CPU 111 transmits the first update request data to the server apparatus S2 (T201). In contrast, the CPU 111 may transmit the first update request data to the server apparatus S2 in response to the reception (T115) of the connection completion notification data (T113) from the terminal apparatus C1 transmitted in response to the establishment of the link connection between the terminal apparatus C1 and the server apparatus S2.
The CPU 211 of the terminal apparatus C1 suspends the transmission processing (V301) during the period after the ACK is transmitted to the server apparatus S1 in T121 and before the switching completion notification data is transmitted to the server apparatus S1 in T305. In contrast, the CPU 211 may continue to transmit the conference data to the server apparatus S1 during the period from T121 to T305.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-052009 | Mar 2018 | JP | national |
