WO2014050125A1

WO2014050125A1 - Communication system, control apparatus, terminal, terminal control method, and program

Info

Publication number: WO2014050125A1
Application number: PCT/JP2013/005746
Authority: WO
Inventors: Shuichi Karino
Original assignee: Nec Corporation
Priority date: 2012-09-28
Filing date: 2013-09-26
Publication date: 2014-04-03
Also published as: JP2015530766A

Abstract

Provided is a control apparatus that can reduce load on a control apparatus or a network based on behavior of terminals. The communication system includes: a control apparatus comprising a first means detecting, when a first condition commonly set in a plurality of terminals is satisfied, communication executed by each of the plurality of terminals and a second means instructing, when the communication is detected, at least one of the plurality of terminals to execute the communication based on a second condition different from the first condition; and a terminal(s) comprising a third means executing, when receiving an instruction from the control apparatus, the communication based on the second condition.

Description

COMMUNICATION SYSTEM, CONTROL APPARATUS, TERMINAL, TERMINAL CONTROL METHOD, AND PROGRAM

Field

The present invention is based upon and claims the benefit of the priority of Japanese patent application No. 2012-217854, filed on September 28, 2012, the disclosure of which is incorporated herein in its entirety by reference thereto.
The present invention relates to a communication system, a control apparatus, a terminal, a terminal control method, and a program. In particular, it relates to: a communication system including a group of terminals and a control apparatus controlling these terminals in a central manner; a control apparatus; a terminal; a terminal control method; and a program.

Background

There are application programs (hereinafter referred to as "applications") that start communication at a predetermined time or under a predetermined condition, such as communication for data synchronization. For example, terminals in which applications of this type are installed start communication simultaneously at the same time or under the same condition. As a result, spiked traffic that rapidly increases and decreases within a relatively short time is observed on packet paths that lead to a server as a communication destination of these applications.

In recent years, a technique referred to as OpenFlow has been proposed (see non patent literature (NPL) 1 and 2). OpenFlow recognizes communications as end-to-end flows and performs path control, failure recovery, load balancing, and optimization on a per-flow basis. An OpenFlow switch according to NPL 2 has a secure channel for communication with an OpenFlow controller and operates according to a flow table suitably added or rewritten by the OpenFlow controller. In a flow table, a set of the following three is defined for each flow: matching conditions (Match Fields) against which a packet header is matched; flow statistical information (Counters); and Instructions that define processing contents (see section "4.1 Flow Table" in NPL 2).

For example, when receiving a packet, the OpenFlow switch searches the flow table for an entry having a matching condition (see "4.3 Match Fields" in NPL 2) that matches header information of the incoming packet. If, as a result of the search, the OpenFlow switch finds an entry matching the incoming packet, the OpenFlow switch updates the flow statistical information (Counters) and processes the incoming packet based on a processing content (packet transmission from a specified port, flooding, drop, etc.) written in the Instructions field of the entry. If, as a result of the search, the OpenFlow switch does not find an entry matching the incoming packet, the OpenFlow switch transmits an entry setting request (Packet-In message) to the OpenFlow controller via the secure channel. Namely, the OpenFlow switch requests the OpenFlow controller to transmit control information for processing the incoming packet. The OpenFlow switch receives a flow entry defining a processing content and updates the flow table. In this way, by using an entry stored in the flow table as control information, the OpenFlow switch executes packet forwarding.

Nick McKeown, and seven others, "OpenFlow: Enabling Innovation in Campus Networks," [online], [searched on July 13, 2012], Internet <URL:http://www.openflow.org/documents/openflow-wp-latest.pdf> "OpenFlow Switch Specification" Version 1.1.0 Implemented (Wire Protocol 0x02), [online], [searched on July 13, 2012], Internet <URL:http://www.openflow.org/documents/openflow-spec-v1.1.0.pdf>

Summary

The following analysis has been given by the present invention. If the above spiked traffic is generated, network congestion or packet loss could be caused. Particularly, with the recent spread of high-function terminals as typified by smartphones and various applications, such spiked traffic could be generated more frequently, and therefore, prompt measures are demanded.

It is an object of the present invention to provide: a communication system that can contribute to reduction in load on a control apparatus or a network based on behavior of terminals, such as reduction in the occurrence frequency of the above spiked traffic; a control apparatus; a terminal; a terminal control method; and a program.

According to a first aspect, there is provided a communication system. The communication system comprises: a control apparatus comprising a first means detecting, when a first condition commonly set in a plurality of terminals is satisfied, communication executed by each of the plurality of terminals, and a second means instructing, when the communication is detected, at least one of the plurality of terminals to execute the communication based on a second condition different from the first condition. The system further comprises a terminal(s) comprising a third means executing, when receiving an instruction from the control apparatus, the communication based on the second condition.

According to a second aspect, there is provided a control apparatus. The control apparatus comprises: a first means detecting, when a first condition commonly set in a plurality of terminals is satisfied, communication executed by each of the plurality of terminals; and a second means instructing, when the communication is detected, at least one of the plurality of terminals to execute the communication based on a second condition different from the first condition.

According to a third aspect, there is provided a terminal, connected to a control apparatus. The control apparatus comprises a first means detecting, when a first condition commonly set in a plurality of terminals is satisfied, communication executed by each of the plurality of terminals. The terminal comprises: a third means executing, when receiving an instruction from the control apparatus, the communication based on a second condition different from the first condition.

According to a fourth aspect, there is provided a terminal control method. The method comprises steps of: detecting, when a first condition commonly set in a plurality of terminals is satisfied, communication executed by each of the plurality of terminals; and instructing, when the communication is detected, at least one of the plurality of terminals to execute the communication based on a second condition different from the first condition. This method is associated with a certain machine, that is, with the control apparatus controlling the terminals in a central manner.

According to a fifth aspect, there is provided a program causing a computer included in a control apparatus to execute processes of: detecting, when a first condition commonly set in a plurality of terminals is satisfied, communication executed by each of the plurality of terminals; and instructing, when the communication is detected, at least one of the plurality of terminals to execute the communication based on a second condition different from the first condition. This program can be recorded in a computer-readable (non-transient) storage medium. Namely, the present invention can be embodied as a computer program product.

The present invention can contribute to reduction in load on a control apparatus or a network based on behavior of terminals, such as spiked traffic generated by behavior of the above applications.

Fig. 1 illustrates a configuration according to an exemplary embodiment of the present disclosure. Fig. 2 is a diagram for illustrating an operation according to the exemplary embodiment of the present disclosure. Fig. 3 is a diagram for illustrating an operation according to the exemplary embodiment of the present disclosure. Fig. 4 illustrates a configuration of a communication system according to a first exemplary embodiment of the present disclosure. Fig. 5 is a flowchart illustrating an operation of the communication system according to the first exemplary embodiment of the present disclosure. Fig. 6 is a flowchart illustrating a flow of traffic analysis processing executed by a control apparatus according to the first exemplary embodiment of the present disclosure. Fig. 7 illustrates the traffic analysis processing executed by the control apparatus according to the first exemplary embodiment of the present disclosure. Fig. 8 illustrates the traffic analysis processing executed by the control apparatus according to the first exemplary embodiment of the present disclosure. Fig. 9 illustrates the traffic analysis processing executed by the control apparatus according to the first exemplary embodiment of the present disclosure. Fig. 10 is a graph illustrating aggregated results in Fig. 9. Fig. 11 illustrates a control target flow selected from the aggregated results in Fig. 9. Fig. 12 illustrates a communication delay operation executed by a terminal according to the first exemplary embodiment of the present disclosure. Fig. 13 illustrates the communication delay operation executed by the terminal according to the first exemplary embodiment of the present disclosure. Fig. 14 illustrates the communication delay operation executed by the terminal according to the first exemplary embodiment of the present disclosure. Fig. 15 illustrates a communication delay operation executed by a terminal according to a second exemplary embodiment of the present disclosure. Fig. 16 illustrates a configuration according to an exemplary embodiment of the present disclosure.

First, an outline of an exemplary embodiment of the present disclosure will be described with reference to the drawings. In the following outline, various components are denoted by reference characters for the sake of convenience. Namely, the following reference characters are merely used as examples to facilitate understanding of the present disclosure, not to limit the present invention to the illustrated modes.

As illustrated in Fig. 16, an exemplary embodiment of the present disclosure can be realized by a configuration including a plurality of terminals 1 and a control apparatus 2. A common first condition is set in each of the terminals 1. For example, the first condition is that an application starts communication at a predetermined time or in response to a predetermined operation executed on a terminal. More specifically, for example, the first condition is that a plurality of terminals simultaneously execute communication at 13:00 and 20:00 every day within a very short time.

If a plurality of terminals execute communication under the first condition in this way, the above spiked traffic is generated. This spiked traffic is generated by a rapid increase in the amount of communication in the network within a short time or by many terminals simultaneously exchanging control signals with the network. In addition, as a result of such spiked traffic, network congestion or packet loss could be caused.

The control apparatus 2 has a function of detecting communication executed by each of the plurality of terminals under the first condition. For example, the control apparatus detects spiked traffic as illustrated in Fig. 2.

In addition, the control apparatus 2 has a function of instructing at least one of the plurality of terminals 1 to execute certain communication based on a second condition.

Examples of the second condition include changing the time when the terminal starts the communication and changing the communication interface used by the terminal for the communication.

The terminal executes the communication in accordance with an instruction from the control apparatus. For example, if, as the second condition, the terminal is instructed to change the start time of the communication, the terminal changes the start time of the communication. The terminal may advance or delay the start time of the communication. If, as the second condition, the terminal is instructed to change the communication interface for the communication, the terminal changes the communication interface used for the communication from a communication interface corresponding to a mobile network to a communication interface corresponding to WiFi (registered mark).

As described above, the control apparatus instructs at least one terminal to execute communication based on the second condition, and in response to such instruction from the control apparatus, the terminal executes communication based on the second condition. In this way, the above spiked traffic can be avoided. Thus, a plurality of terminals simultaneously start communication under the first condition at the same time, the amount of communication and the number of terminals executing communication can be distributed or smoothed.

As illustrated in Fig. 1, another exemplary embodiment of the present disclosure can be realized by a configuration including a plurality of terminals 10A and a control apparatus 20A. More specifically, the control apparatus 20A includes: a statistical information collection unit 21A collecting statistical information about communication from a plurality of control target terminals; a statistical information analysis unit 22A detecting a timing at which concentration of communication to a certain destination is caused by a plurality of terminals simultaneously starting communication, based on the collected statistical information; and a control instruction unit 23A instructing, when the statistical information analysis unit 22A detects a timing at which concentration of the communication to the certain destination is caused, at least one terminal selected from the plurality of terminals to execute a control operation on the corresponding communication. Each of the terminals 10A includes a communication control unit 11A controlling the corresponding communication based on an instruction from the control apparatus 20A. More specifically, the concentration of communication can be detected by using various types of statistical values which can be acquired from communication statistical information and which will be described below. Examples of the statistical values include a traffic amount, the number of simultaneously-connected terminals that are connected (Attached) to a mobile network, or the number of terminals connected to a certain destination. Herein, for example, the traffic amount signifies a data amount transmitted from a terminal to a mobile network or to a certain destination or a data amount of control signals generated until connection between a terminal and a mobile network is set.

Fig. 2 illustrates change of traffic to a certain destination in a network in which many terminals are connected, each of the terminals including an application (see 13A in Fig. 1) that starts communication to the certain destination at a certain time or under a certain condition. For example, the certain destination is a server with which the applications included in the respective terminals start communication. In Fig. 2, the traffic has spiked waveforms, each of which rapidly increases and decreases within a very short time at 13:00 and 20:00 every day. From such traffic change, the statistical information analysis unit 22A detects that there are timings at which concentration of traffic to a certain destination is caused, namely, at 13:00 and 20:00 every day. Next, the control instruction unit 23A causes at least one terminal, which is selected from these terminals that start communication at 13:00 and 20:00 every day based on a predetermined reference, to execute a control operation on the corresponding communication. Various modes can be adopted as the instruction for controlling the communication. For example, the terminal is instructed to shift (advance or delay) the start time of the communication, to temporarily discard a packet relating to the communication and to retransmit the packet after a predetermined time, to insert a dummy packet or the like between packets relating to the communication, or to change the forwarding path of the communication (for example, from via a mobile network to via a wireless LAN or WiMAX (Worldwide Interoperability for Microwave Access)).

The control apparatus 20A detects the timings at which concentration of communication is caused, if the increase

in the traffic amount at a certain observation time exceeds a predetermined threshold (a first threshold), the decrease

in the traffic amount within a predetermined time (a first time t1) exceeds a predetermined threshold (a second threshold), and such rapid increase and decrease pattern (spiked traffic) appears in a substantially regular cycle (t2 in Fig. 2) (see Fig. 2). If the number of terminals connected to a mobile network or the number of terminals connected to a certain site is used as the statistical value, as in the case with the above traffic amount, the increase and the decrease in the number of terminals can be used to detect concentration of communication. Namely, the present invention is applicable, as long as whether the traffic amount or the number of terminals simultaneously connected to a mobile network or a certain destination is rapidly increased within a short time can be detected.

For example, if a terminal is instructed by the control apparatus to delay the start time of communication, the terminals delay the start time of the communication by the time instructed by the control apparatus 20A or by the time determined by random numbers. In this way, as illustrated by a thick line in Fig. 3, the start time of the communication to a certain destination can be distributed. In this way, occurrence of network congestion or packet loss can be reduced. In addition, in a central-control-system network as in

NPL

1 and 2, generation timings of control signals (for example, a Packet-In message used when a new flow is detected and a control signal generated until connection between a terminal and a mobile network is set) to the control apparatus can be distributed, and as a result, load on the control apparatus can be reduced.

<First exemplary embodiment>
Next, a first exemplary embodiment of the present disclosure will be described in detail with reference to the drawings. Fig. 4 illustrates a configuration of a communication system according to the first exemplary embodiment of the present disclosure. Referring to Fig. 4, the configuration includes a plurality of terminals 10 and a control apparatus 20.

Each terminal 10 includes a communication control unit 11, a packet transmission unit 12, an application 13, and a flow table 14.

The communication control unit 11 rewrites a flow entry stored in the flow table 14 in accordance with an instruction from the control apparatus 20. In addition, when receiving a transmission packet from the application 13, the communication control unit 11 outputs the packet to the packet transmission unit 12. In addition, based on a request from the packet transmission unit 12, the communication control unit 11 transmits a flow entry setting request (Packet-In message) to the control apparatus 20, for example.

When receiving a transmission packet from the application 13 via the communication control unit 11, the packet transmission unit 12 searches the flow table 14 for an entry having a matching condition matching a header or the like of the transmission packet. As a result of the search, if the packet transmission unit 12 finds an entry having a matching condition matching a header or the like of the transmission packet, the packet transmission unit 12 executes processing content stored in the instruction field of the entry (packet transmission from a specified port, header rewriting, etc.). In addition, in this case, the packet transmission unit 12 updates a value in the flow statistical information (Counters) field of the entry used for packet transmission.

However, if, as a result of the search, if the packet transmission unit 12 does not find an entry having a matching condition matching a header or the like of the transmission packet, the packet transmission unit 12 requests the control apparatus 20 to set a flow entry for processing the transmission packet via the communication control unit 11.

The application 13 is an application program that starts communication to a certain destination and executes data synchronization or the like at a certain time or under a predetermined condition.

The flow table 14 is a table storing entries for processing packets matching conditions, as in a flow table of an OpenFlow switch in NPL 2.

For example, each of the above terminals 10 is an arbitrary type of information processing apparatus (a mobile terminal, a personal computer, etc.). In addition, a terminal 10 can be realized by a terminal having a function equivalent to that of an OpenFlow switch in NPL 2. In addition, a terminal 10 may be a component in an M2M (Machine to Machine) system.

The control apparatus 20 includes a traffic information collection unit 21, a traffic analysis unit 22, and a delay instruction unit 23.

At predetermined time intervals, the traffic information collection unit 21 queries the communication control unit 11 of each terminal about a value in the flow statistical information (Counters) field of each entry in the flow table 14 and collects traffic information. To collect such traffic information, a Read State message in NPL 2, which is for querying a switch (a terminal 10 including a switching function) about content of the flow table 14, can be used ("see A.3.6 Read State Message" in NPL 2).

Based on the traffic information collected from each terminal, the traffic analysis unit 22 aggregates traffic amounts per time by destination and selects a destination, for which a rapid increase and a rapid decrease in traffic amount are regularly observed, as a target for delaying the start time of the communication. The traffic analysis unit 22 determines a timing at which the traffic to the selected destination is rapidly increased next and notifies the delay instruction unit 23 of the timing.

Based on the notification content supplied from the traffic analysis unit 22, the delay instruction unit 23 instructs at least one terminal selected from the plurality of terminals 10 based on a predetermined rule to delay the start time of the communication determined by the traffic analysis unit 22. More specifically, by causing the terminal 10 to rewrite content of the instruction field of a flow entry for processing the corresponding communication, the delay instruction unit 23 delays the start time of the communication.

The traffic analysis processing executed by the traffic analysis unit 22 and the communication start time delaying method executed by the delay instruction unit 23 will be described in detail based on specific examples.

The above control apparatus 20 can be realized by adding the traffic analysis unit 22 and the delay instruction unit 23 to the OpenFlow controller in NPL 2.

Each unit (processing means) of the control apparatus 20 (20A) in Fig. 4 (1) can be realized by a computer program causing a computer constituting the control apparatus 20 to use its hardware and to execute each processing described above.

Next, an operation according to the present exemplary embodiment will be described in detail with reference to the drawings. Fig. 5 is a flowchart illustrating an operation of the communication system according to the first exemplary embodiment of the present disclosure. Referring to Fig. 5, first, the control apparatus 20 collects traffic information from the plurality of control target terminals 10 at predetermined timings (for example, at intervals of n minutes) (steps S001 and S101).

Next, based on the collected traffic information, the control apparatus 20 determines a communication destination with which terminals of a predetermined number or more simultaneously start communication and the timings (step S002; analyze traffic).

As a result of the traffic analysis, if the control apparatus 20 determines a communication destination with which terminals of a predetermined number or more simultaneously start communication and the timings (Yes in step S003; detection of control target traffic), the control apparatus 20 selects at least one control target terminal based on a predetermined rule and transmits a delay instruction to the selected terminals (step S004).

After receiving the instruction and executing predetermined delay processing (for example, storage in a packet queue or a transmission buffer, transmission wait processing, etc.) (step S102), the terminal 10 transmits the packet (step S103).

An example of the traffic analysis processing executed by the control apparatus 20 in the above step S002 will be described in detail with reference to the drawings.

Fig. 6 is a flowchart illustrating a flow of the traffic analysis processing executed by the control apparatus according to the first exemplary embodiment of the present disclosure. Referring to Fig. 6, first, the control apparatus 20 aggregates traffic information received from each terminal 10 and creates a list of control target flow candidates (step S201). This list of control target flow candidates is stored for a predetermined time.

Fig. 7 is an example of such list of control target candidates created in step S201 in Fig. 6. Referring to Fig. 7, the list of control target candidates is created by aggregating a traffic amount by destination in a predetermined time slot (one minute in Figs. 7 to 9), based on the traffic information collected from each terminal 10. Information of arbitrary granularity such as the number of packets, the number of bytes, etc. can be used as the traffic amount. In addition, in Fig. 7, a list of control target candidates for m time slots is stored.

Next, the control apparatus 20 removes any entry having a traffic amount less than a predetermined threshold from the entries in the list of control target candidates (step S202).

Fig. 8 illustrates an entry to be removed from the list of control target candidates in Fig. 7. This entry has a destination for which the traffic amount is less than a predetermined threshold. In addition, in Fig. 8, while a value 1000 is set as the predetermined threshold, an arbitrary threshold may be set depending on a feature of the control target traffic or a feature of another communication traffic that may cause an erroneous determination.

Next, the control apparatus 20 refers to the list of control target flow candidates in a plurality of past time slots and determines a destination generating spiked increase and decrease patterns periodically and a timing at which the next spiked increase and decrease pattern may be generated (step S203).

Fig. 9 illustrates a list of control target candidates that is obtained by removing entries having traffic amounts less than the predetermined threshold from the entries in the list of control target candidates (m time slots).

Fig. 10 is a graph in which the traffic amounts in the list of control target candidates in Fig. 9 are represented by destination. For example, in Fig. 10, communication to a destination 192.168.10.5 generates spiked traffic in time slots 14:00-14:01, 15:00-15:01, and 16:00-16:01. As in the communication to the destination 192.168.10.5, if the number of connected terminals communicating with a destination is a threshold or more in a certain time slot and if periodicity or a feature is seen in change of the number of the connected terminals, this communication is determined to be a control target. For example, periodicity of change in the number of the connected terminals can be detected by the following method. First, communication as a control target is narrowed down from the table in Fig. 9 (Fig. 11) or the graph in Fig. 10 for a first predetermined time (for example, one day or several hours). Next, regarding the communication as a control target, the past record about the number of connected terminals is examined for a second predetermined time (several days or several hours). If occurrence time of the communication as the control target during the second predetermined time is the same as the occurrence time during the first predetermined time, the communication as a control target is determined to have periodicity.

In contrast, unlike in the communication to the destination 192.168.10.5, it is seen that, in communication to a destination 192.168.0.1 and in communication to a destination 192.168.5.10, the number of connected terminals is not concentrated only within a certain time slot. In addition, unlike in the communication to the destination 192.168.10.5, no periodicity is seen in change of the traffic amount. Thus, the communication to the destination 192.168.0.1 and the communication to the destination 192.168.5.10 can be removed from the control target list. As described above, from the traffic feature as illustrated in Fig. 10, the control apparatus 20 determines that packets to the destination 192.168.10.5 belong to the control target communication, as illustrated in Fig. 11. In addition, the control apparatus 20 determines that the next spiked traffic is generated every hour such as at 17:00-17:01 and 18:00-18:01 or at 14:00-14:01, 15:00-15:01, and 16:00-16:01 next day.

After determining the control target communication and the timings, the control apparatus 20 instructs the terminals 10, which are selected by using a predetermined rule so that the traffic can be distributed, to delay the start time of the control target communication.

For example, as illustrated in Fig. 12, the control apparatus 20 instructs a target terminal to rewrite a value in the instruction field of a control target flow entry from "output from a specified port (Output port#R)" to "storage in a queue (ENQUEUE)."

By rewriting a value in the instruction field in this way, if a packet transferred from the application 13 is a packet belonging to the control target communication, the corresponding terminal 10 stores the packet in a queue and transmits the packet after a predetermined time elapses, as illustrated in Fig. 13.

The control apparatus 20 may instruct each terminal 10 about the period of storage in the queue so that the traffic distribution effect can be achieved. Alternatively, each terminal may determine the period of storage in the queue by using random numbers or the like.

For example, by using uniform random numbers as the random numbers, as illustrated in Fig. 14, spiked traffic is changed to rectangular traffic in which the flow amount per time falls within a predetermined range. In this way, generation of network congestion or packet loss is reduced. In addition, generation timings of control signals (for example, a Packet-In message from an OpenFlow switch on a path and a control signal generated until connection between a terminal and a mobile network is set) to the control apparatus 20 can be distributed, and as a result, load on the control apparatus 20 can be reduced.

While an exemplary embodiment of the present disclosure has thus been described, the present invention is not limited thereto. Further variations, substitutions, or adjustments can be made without departing from the basic technical concept of the present disclosure. For example, network configurations and component configurations illustrated in the drawings are examples to facilitate understanding of the present disclosure. Namely, the present invention is not limited to the configurations illustrated in these drawings.

<Second exemplary embodiment>
In the above exemplary embodiment, spiked traffic is smoothed by storing transmission packets in a queue. However, other methods may be used. For example, as illustrated in Fig. 15, concentration of the traffic (communication) to the certain destination can be smoothed by causing each terminal 10 to transmit a dummy packet having a different destination between packets relating to the communication.

Fig. 15 illustrates an example where n control target packets are transmitted. In Fig. 15, the packet transmission unit transmits a single dummy packet every time the packet transmission unit transmits a single control target packet. In this way, by causing the packet transmission unit to transmit a single dummy packet every time the packet transmission unit transmits a single control target packet, the time required for transmitting the n control target packets can be extended (delayed). In this case, since the dummy packets are eventually discarded, an arbitrary destination may be set for the dummy packets. For example, the dummy packets may be transmitted to the communication control unit 11 or the packet transmission unit 12 in a terminal and the dummy packet may be discarded subsequently. Alternatively, a destination only for the dummy packets may be prepared, and all the dummy packets received by the destination may be discarded.

More desirably, a different transmission priority may be set in the control target packets from that of the dummy packets. For example, by setting a higher transmission priority in the dummy packets than that of the control target packets, transmission of the control target packets can be delayed. Thus, by distributing timings at which each terminal transmits the control target packets, concentration of the traffic (communication) to the certain destination can be smoothed.

In another method for delaying transmission of the control target packets, the control target packets are temporarily discarded first and are retransmitted next. More specifically, first, a control target packet is discarded by the communication control unit 11, the packet transmission unit 12, etc. in a terminal. Next, after a certain time (packet discard processing execution time) elapses, the discarded control target packet is retransmitted from the communication control unit 11 or the packet transmission unit 12 in the terminal. Transmission of control target packet can be delayed in this way, too. In addition, in such case, by setting different values as the packet discard processing execution time that the respective terminals are instructed to set, the timings at which the respective terminals transmit the control target packets can be distributed. Thus, concentration of the traffic (communication) to the certain destination can be smoothed.

A terminal 10 may include a virtual control apparatus having a function equivalent to that of the control apparatus 20. In such case, the following operation can be executed. If a terminal 10 includes such virtual control apparatus, the virtual control apparatus in the terminal relays a control signal to the control apparatus 20. Since the virtual control apparatus in the terminal discards a flow entry setting request message (Packet-In message) for a control target flow for a predetermined time or a predetermined number of times, concentration of the traffic (communication) to the certain destination can be smoothed, as in the above packet discarding. In addition, the virtual control apparatus in the terminal can be operated in the same way as the queue described in the first exemplary embodiment. More specifically, the virtual control apparatus may be configured so that, when receiving a flow entry setting request message for a control target flow, the virtual control apparatus stores the request message for a predetermined time.

In addition, in the above exemplary embodiment, concentration of the traffic (communication) to the certain destination is smoothed by delaying the control target packet transmission time. However, by advancing the control target packet transmission time, the same advantageous effect can be obtained. For example, the control apparatus 20 may advance the time in a terminal 10. In this way, the transmission time of packets from an application or the like in the terminal 10 can be advanced. In addition, for example, a timer in an application included in a terminal 10 may be advanced. In this case, the application having a timer to be advanced needs to be determined. For example, by causing the control apparatus 20 to determine the port number of the application executing the control target communication, the target application can be determined.

Conventionally, a developer of the application 13 adjusts communication timings of the application or communication timings by using random numbers or the like before shipping (when the application 13 can be transmitted) as needed. However, in the above way, concentration of communication of transmission timings can be smoothed on the network side, without inclusion of such adjustment. In addition, a user does not need to execute an operation of changing application settings, such as adjustment of communication timings.

In addition, in the above exemplary embodiment, concentration of the traffic (communication) to the certain destination is smoothed by delaying the control target packet transmission time. However, a control operation of changing a packet transmission path can also be executed. If control target communication is generated, by changing connection from via a mobile network to via another mobile network or a wireless LAN access point, load on the mobile network can be reduced. More specifically, for example, the control apparatus 20 is configured to previously grasp communication interfaces of each terminal 10 and to instruct the packet transmission unit to change the interface as a transmission destination of the corresponding packets. In addition, in a mobile network, each time a terminal connects the mobile network to start communication, a resource needs to be ensured and information needs to be managed per terminal. However, according to the present invention, problems such as an increase in the number of control signal on the mobile network side and an increase in server load can be solved.

In addition, in the above exemplary embodiment, a flow generating spiked traffic in a predetermined cycle is determined to be a control target flow. However, for example, the present invention is also applicable when generation of spiked traffic is anticipated based on some rule. For example, the present invention is applicable at the time of a natural phenomenon such as sunrise or sunset, on the arrival of a public holiday, at the start of a certain television program, at the start of a time-limited sale, and on the occurrence of an event such as an update of a microblog by a prominent person, for example.

In addition, a data amount transmitted from a terminal to a mobile network or a certain destination or a data amount of control signals generated until connection between a terminal and a mobile network is set can be used as a traffic amount, for example. In addition, as an alternative to the traffic amount, the number of terminals connected to a mobile network or the number of terminals connected to a certain site can be used. In such case, as in the traffic amount, concentration of communication can be detected by using the increase and decrease in the number of terminals. Namely, the present invention is applicable as long as whether the traffic amount or the number of terminals simultaneously connected to a mobile network or a certain destination is rapidly increased within a short time can be detected.

Finally, preferable modes of the present disclosure will be summarized.
<First mode>
(See the communication system according to the above first aspect)
<Second mode>
In the communication system in the first mode, the second condition is delaying the start time of the communication.
<Third mode>
In the communication system in the first or second mode, the terminal(s) comprises a queue storing a transmission target packet for a predetermined time, and the third means delays the start of the communication by storing a packet specified by the control apparatus in the queue and transmitting the packet subsequently.
<Fourth mode>
In the communication system in the third mode, a period of time between when the transmission target packet is stored in the queue and when the packet is transmitted is determined by uniform random numbers.
<Fifth mode>
In the communication system in the first or second mode, the second condition is advancing start time of the communication.
<Sixth mode>
In the communication system in the first or second mode, the second condition is changing a communication interface used for the communication.
<Seventh mode>
In the communication system in the first or second mode, the second condition is discarding a packet relating to the communication for a predetermined time and retransmitting the packet subsequently.
<Eighth mode>
In the communication system in the first or second mode, the second condition is transmitting a dummy packet between packets relating to the communication.
<Ninth mode>
In the communication system in any one of the first to eighth modes, the first condition is that the plurality of terminals execute communication within a predetermined time.
<Tenth mode>
In the communication system in any one of the first to ninth modes, the first means detects the communication when a statistical value relating to the communication by the plurality of terminals exceeds a threshold within a predetermined time.
<Eleventh mode>
In the communication system in the tenth mode, the statistical value is a traffic amount from the plurality of terminals to a certain destination.
<Twelfth mode>
In the communication system in the tenth mode, the statistical value is the number of terminals connected to a certain destination among the plurality of terminals.
<Thirteenth mode>
In the communication system in the first mode, the first means detects a timing at which concentration of the communication is caused based on statistical information about the communication, the second means instructs, when the first means detects a timing at which concentration of communication to a certain destination is caused, at least one of the terminals executing the communication to the certain destination to delay the start time of the corresponding communication, and the third means delays the start of the corresponding communication in accordance with an instruction from the control apparatus.
<Fourteenth mode>
In the communication system in the thirteenth mode, the control apparatus aggregates a statistical value per time by destination based on the statistical information collected from the plurality of control target terminals, and communication to a destination in which a rapid increase and a rapid decrease of the statistical value regularly occurs within a predetermined time is selected as a target for delaying the communication start time.
<Fifteenth mode>
In the communication system in the fourteenth mode, the control apparatus stores a list of control target candidates in which the aggregated statistical values and destinations, each of which represents that the aggregated statistical value per time by destination exceeds a predetermined threshold, are recorded for a past predetermined time. In addition, the control apparatus refers to the list of control target candidates for the past predetermined time to select a target for delaying the communication start time.
<Sixteenth mode>
In the communication system in any one of the first mode and the thirteenth to fifteenth modes, the terminal(s) comprises a queue as the third means storing a transmission target packet for a predetermined time, and the terminal(s) delays the start of the corresponding communication by storing a packet specified by the control apparatus in the queue and transmitting the packet subsequently.
<Seventeenth mode>
In the communication system in the sixteenth mode, the time between when the transmission target packet is stored in the queue and when the packet is transmitted is determined by uniform random numbers.
<Eighteenth mode>
In the communication system in any one of the first and the thirteenth to sixteenth modes, as an instruction for controlling the communication by the second means, concentration of communication to the certain destination is smoothed by advancing the transmission time of a packet relating to the corresponding communication.
<Nineteenth mode>
In the communication system in any one of the first and the thirteenth to sixteenth modes, as an instruction for controlling the communication by the second means, concentration of communication to the certain destination is smoothed by changing a forwarding path of a packet relating to the corresponding communication.
<Twentieth mode>
In the communication system in any one of the first and the thirteenth to sixteenth modes, as an instruction for controlling the communication by the second means, concentration of communication to the certain destination is smoothed by causing the terminal(s) to discard a packet relating to the corresponding communication for a predetermined time and to retransmit the packet subsequently.
<Twenty-first mode>
In the communication system in any one of the first and the thirteenth to sixteenth modes, as an instruction for controlling the communication by the second means, concentration of communication to the certain destination is smoothed by causing the terminal(s) to transmit a dummy packet between packets relating to the corresponding communication.
<Twenty-second mode>
In the communication system in any one of the first and the thirteenth to twenty-first modes, the statistical value is a traffic amount to the certain destination.
<Twenty-third mode>
In the communication system in any one of the first and the thirteenth to twenty-second modes, the statistical value is the number of terminals connected to the certain destination among the plurality of terminals.
<Twenty-fourth mode>
(See the control apparatus according to the above second aspect)
<Twenty-fifth mode>
(See the terminal according to the above third aspect)
<Twenty-sixth mode>
(See the terminal control method according to the above fourth aspect)
<Twenty-seventh mode>
(See the program according to the above fifth aspect)
The above twenty-fourth to twenty-seventh modes can be extended to the second to twenty-third modes, as in the first mode.

The entire disclosure of the above NPL is incorporated herein by reference thereto. Modifications and adjustments of the exemplary embodiments and examples are possible within the scope of the overall disclosure (including the claims) of the present invention and based on the basic technical concept of the present invention. Various combinations and selections of various disclosed elements (including the elements in each of the claims, exemplary embodiments, examples, drawings, etc.) are possible within the scope of the claims of the present invention. That is, the present invention of course includes various variations and modifications that could be made by those skilled in the art according to the overall disclosure including the claims and the technical concept. The description discloses numerical value ranges. However, even if the description does not particularly disclose arbitrary numerical values or small ranges included in the ranges, these values and ranges should be deemed to have been specifically disclosed. Note that singular form of the term will represent also the plural form as the case is relevant or necessary.

1, 10, 10A terminal
2, 20, 20A control apparatus
21 traffic information collection unit
21A statistical information collection unit
22 traffic analysis unit
22A statistical information analysis unit
23 delay instruction unit
23A control instruction unit
11, 11A communication control unit
12, 12A packet transmission unit
13, 13A application
14 flow table

Claims

A communication system, comprising:
a control apparatus comprising a first means detecting, when a first condition commonly set in a plurality of terminals is satisfied, communication executed by each of the plurality of terminals and a second means instructing, when the communication is detected, at least one of the plurality of terminals to execute the communication based on a second condition different from the first condition; and
a terminal(s) comprising a third means executing, when receiving an instruction from the control apparatus, the communication based on the second condition.
The communication system according to claim 1;
wherein the second condition is delaying start time of the communication.
The communication system according to claim 1 or 2;
wherein the terminal(s) comprises a queue storing a transmission target packet for a predetermined time;
wherein the third means delays the start of the communication by storing a packet specified by the control apparatus in the queue and transmitting the packet subsequently.
The communication system according to claim 3;
wherein a period of time between when the transmission target packet is stored in the queue and when the packet is transmitted is determined by uniform random numbers.
The communication system according to claim 1 or 2;
wherein the second condition is advancing start time of the communication.
The communication system according to claim 1 or 2;
wherein the second condition is changing a communication interface used for the communication.
The communication system according to claim 1 or 2;
wherein the second condition is discarding a packet relating to the communication for a predetermined time and retransmitting the packet subsequently.
The communication system according to claim 1 or 2;
wherein the second condition is transmitting a dummy packet between packets relating to the communication.
The communication system according to any one of claims 1 to 8;
wherein the first condition is that the plurality of terminals execute communication within a predetermined time.
The communication system according to any one of claims 1 to 9;
wherein the first means detects the communication when a statistical value relating to the communication by the plurality of terminals exceeds a threshold within a predetermined time.
The communication system according to claim 10;
wherein the statistical value is a traffic amount from the plurality of terminals to a certain destination.
The communication system according to claim 10;
wherein the statistical value is the number of terminals connected to a certain destination among the plurality of terminals.
A control apparatus, comprising:
a first means detecting, when a first condition commonly set in a plurality of terminals is satisfied, communication executed by each of the plurality of terminals; and
a second means instructing, when the communication is detected, at least one of the plurality of terminals to execute the communication based on a second condition different from the first condition.
The control apparatus according to claim 13;
wherein the second condition is delaying start time of the communication.
The control apparatus according to claim 13 or 14;
wherein the second means delays start of the communication by storing a packet specified by the control apparatus in a queue that is included in the terminal(s) for storing a transmission target packet for a predetermined time and transmitting the packet subsequently.
The control apparatus according to claim 15;
wherein a period of time between when the transmission target packet is stored in the queue and when the packet is transmitted is determined by uniform random numbers.
The control apparatus according to claim 13 or 14;
wherein the second condition is advancing start time of the communication.
The control apparatus according to claim 13 or 14;
wherein the second condition is changing a communication interface used for the communication.
The control apparatus according to claim 13 or 14;
wherein the second condition is discarding a packet relating to the communication for a predetermined time and retransmitting the packet subsequently.
The control apparatus according to claim 13 or 14;
wherein the second condition is transmitting a dummy packet between packets relating to the communication.
The control apparatus according to any one of claims 13 to 20;
wherein the first condition is that the plurality of terminals execute communication within a predetermined time.
The control apparatus according to any one of claims 13 to 21;
wherein the first means detects the communication when a statistical value relating to the communication by the plurality of terminals exceeds a threshold within a predetermined time.
The control apparatus according to claim 22;
wherein the statistical value is a traffic amount from the plurality of terminals to a certain destination.
The control apparatus according to claim 22;
wherein the statistical value is the number of terminals connected to a certain destination among the pluraltiy of terminals.
A terminal, connected to a control apparatus comprising a first means detecting, when a first condition commonly set in a plurality of terminals is satisfied, communication executed by each of the plurality of terminals, the terminal comprising:
a third means executing, when receiving an instruction from the control apparatus, the communication based on a second condition different from the first condition.
A terminal control method, comprising steps of:
detecting, when a first condition commonly set in a plurality of terminals is satisfied, communication executed by each of the plurality of terminals; and
instructing, when the communication is detected, at least one of the plurality of terminals to execute the communication based on a second condition different from the first condition.
A program, causing a computer included in a control apparatus to execute processes of:
detecting, when a first condition commonly set in a plurality of terminals is satisfied, communication executed by each of the plurality of terminals; and
instructing, when the communication is detected, at least one of the plurality of terminals to execute the communication based on a second condition different from the first condition.