US-12627405-B2 - Redundancy control device, redundancy control method, and redundancy control program

US12627405B2US 12627405 B2US12627405 B2US 12627405B2US-12627405-B2

Abstract

A redundancy of communication in a communication system can be appropriately set. A configuration is provided in which in a server for setting a redundancy for a communication system allowing communication via a network according to a set redundancy, a processor is provided, and the processor is configured to receive, from an application, a use-predicted communication bandwidth which is a communication bandwidth predicted to be used in the network, determine a redundancy limit which is an upper limit of a redundancy in communication by the application based on a communication bandwidth usable in the network and the use-predicted communication bandwidth, and set, in the communication system, a redundancy equal to or less than the determined redundancy limit as the redundancy in the communication by the application.

Inventors

Katsuto SATO
Takafumi Kikuchi
Takeru Chiba

Assignees

HITACHI, LTD.

Dates

Publication Date: 20260512
Application Date: 20240315
Priority Date: 20231124

Claims (6)

1 . A redundancy control device for setting a redundancy for a communication system allowing communication via a network according to a set redundancy, the redundancy control device comprising: a storage unit, wherein the storage unit is configured to store a correspondence relation between a communication quality indicator and redundancy specifying information for specifying a redundancy to be set, and a processor, wherein the processor is configured to: receive, from an application, a use-predicted communication bandwidth which is a communication bandwidth predicted to be used in the network, determine a redundancy limit, which is an upper limit of a redundancy of communication by the application, based on a communication bandwidth usable in the network and the use-predicted communication bandwidth, set, in the communication system, a redundancy equal to or less than the determined redundancy limit as the redundancy of the communication by the application, acquire a communication quality indicator in the network, determine, based on the communication quality indicator, a recommended redundancy for the communication by the application, and determine a smaller value of the redundancy limit and the recommended redundancy as the redundancy of the communication by the application, wherein the processor is further configured to: specify, based on the correspondence relation, redundancy specifying information corresponding to the communication quality indicator, and determine the recommended redundancy based on the redundancy specifying information.
2 . The redundancy control device according to claim 1 , wherein: the application is an application for receiving an input and output request with respect to a predetermined storage connected via the network and executing input and output of data to or from the storage, and the processor is further configured to execute the application and calculate the use-predicted communication bandwidth based on the input and output request.
3 . The redundancy control device according to claim 1 , wherein: a communication priority that is a priority of communication for each of a plurality of applications is stored, and the processor is further configured to determine the redundancy limit based on the communication priority.
4 . The redundancy control device according to claim 1 , wherein: a minimum redundancy, which is a minimum value of the redundancy of the communication for the application, is stored, and the processor is further configured to set the redundancy of the communication by the application to be equal to or larger than the minimum redundancy.
5 . The redundancy control device according to claim 1 , wherein the communication quality indicator is a packet loss rate in the network.
6 . A redundancy control method, executed by a redundancy control device, for setting a redundancy for a communication system allowing communication via a network according to a set redundancy, the method comprising: storing a correspondence relation between a communication quality indicator and redundancy specifying information for specifying a redundancy to be set, receiving, from an application, a use-predicted communication bandwidth which is a communication bandwidth predicted to be used in the network, determining a redundancy limit, which is an upper limit of a redundancy in communication by the application, based on a communication bandwidth usable in the network and the use-predicted communication bandwidth, setting a redundancy equal to or less than the determined redundancy limit in the communication system, acquiring a communication quality indicator in the network, determining, based on the communication quality indicator, a recommended redundancy for the communication by the application, determining a smaller value of the redundancy limit and the recommended redundancy as the redundancy of the communication by the application, wherein determining, based on the communication quality indicator, a recommended redundancy comprises: specifying, based on the correspondence relation, redundancy specifying information corresponding to the acquired communication quality indicator, and determining the recommended redundancy based on the redundancy specifying information.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a redundancy control device and the like for setting a redundancy for a communication system allowing communication via a network according to a set redundancy. 2. Description of Related Art In a public cloud, since resources of a data center are divided and allocated for various users, the resources are shared and used. A CPU, a memory, and the like mounted on a server can separate an influence among the users by using a virtualization function of hardware or the like. On the other hand, the network is difficult to realize complete separation because a fixed separation causes a decrease in use efficiency. Therefore, although a plurality of network switches are connected by a redundant path to provide a sufficient bandwidth, packet loss may occur in a case where communication is concentrated on a specific path. In addition, a platform operator operating a data center may perform maintenance of a network without notifying a user, and packet loss may occur when a failed or aged network switch is replaced at any timing. As a countermeasure against such an abnormal event on such a shared network, it is effective to set a multipath such that communication can be executed through a plurality of paths, and to duplicate and redundantly transmit communication data. In a case where an abnormal event occurs, the communication can be continued without waiting for automatic recovery from the abnormal event by receiving data that has passed through a path that is not affected. In recent years, as shown in NPL 1, standards have been developed for multipath communication, and a multipath TCP communication function has been introduced as a standard function of an operating system. However, when this function is simply used, a trade-off occurs between availability and a usable maximum bandwidth. As a technique for redundancy in communication, for example, PTL 1 discloses redundancy in a time direction in which the number of times of transmission is increased in accordance with a communication state. In addition, PTL 2 discloses that a redundancy is determined based on a communication speed such that a time until transmission is completed is within a certain delay time in accordance with a communication state, and redundant data is added and transmitted using a method such as a forward correction code according to the redundancy. Further, PTL 3 discloses a method of maintaining an order of data in a case where time series data is redundantly transmitted while changing a communication path among a plurality of paths. CITATION LIST Patent Literature PTL 1: JP2023-039257A PTL 2: JP2023-006210A PTL 3: JP2015-122697A Non Patent Literature NPL 1: RFC8684 “TCP Extensions for Multipath Operation with Multiple Addresses” SUMMARY OF THE INVENTION A method of avoiding an abnormal event of a shared network by establishing a multipath and redundantly transferring duplicated data is a trade-off with a usable maximum bandwidth. It is assumed that an occurrence probability of the abnormal event is P (0<P<1) and each abnormal event independently occurs. When a redundancy of communication is N, that is, when data is duplicated to N times thereof and is redundantly transmitted to different paths, it is expected that a probability that an abnormal event affects the communication is reduced to PN. However, since a bandwidth to be used also increases to N times thereof, a usable maximum bandwidth decreases to 1/N. Thus, when the redundancy is fixedly determined, the maximum bandwidth is also fixedly limited. Therefore, it is important how the redundancy of the communication is set. The present invention has been made in view of the above circumstances, and an object thereof is to provide a technique capable of appropriately setting a redundancy of communication in a communication system. In order to achieve the above-mentioned object, a redundancy control device according to one aspect is a redundancy control device for setting a redundancy for a communication system allowing communication via a network according to a set redundancy, and the redundancy control device includes a processor. In the redundancy control device, the processor receives, from an application, a use-predicted communication bandwidth which is a communication bandwidth predicted to be used in the network, determines a redundancy limit which is an upper limit of a redundancy in communication by the based on application a communication bandwidth usable in the network and the use-predicted communication bandwidth, and sets, in the communication system, a redundancy equal to or less than the determined redundancy limit as the redundancy of the communication by the application. According to the present invention, it is possible to appropriately set the redundancy of the communication in the communication system. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a hardware configuration diagram of a com