CMSNS: a communication middleware for social networking and networked multimedia systems

2020

IEEE Access

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In this paper, we propose an efficient direct and indirect file transfer protocol (C2CFTP) that transfers files between clients in a client-server system. Existing file transfer methods use an indirect transfer method through a server to transfer files between sending and receiving clients or a direct transfer method that connects a direct data channel between clients. However, in the case of indirect transmission, unnecessary file input/output (I/O) is required by the server, and in the case of direct transmission, a problem arises in that the file transmission delay time is increased due to channel management cost. The proposed C2CFTP can omit unnecessary file I/O overhead by relaying the file to the receiving client instead of storing the file at the server for indirect transmission. For direct transmission, instead of connecting a data channel every time a file is transmitted, the channel connection overhead is reduced while minimizing the waste of the number of direct channels between clients by maintaining the first connected channel while the file transfer is required within a predetermined time. File transfer experiments show that the proposed file transfer protocol has a reduced file transfer delay time than the existing methods. In addition, it was confirmed that the direct transfer method is suitable for transferring large files, and the indirect transfer method is suitable for transferring multiple small-sized files in a bundle.

Section: Communication Framework (Cm)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

C2CFTP: Direct and Indirect File Transfer Protocols Between Clients in Client-Server Architecture

2020

IEEE Access

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“…CM [1] is a communication framework for developing distributed applications. Using the API and configuration files provided by CM, an application developer can easily implement various communication functions that enable the application to interact with other CM nodes (applications that use CM communication services).…”

Section: Communication Framework (Cm)mentioning

confidence: 99%

“…Many of today’s multiuser-based distributed applications such as online games, social networking systems (SNS), and file sharing systems provide various communication functions for efficient interaction among users. We developed a communication framework called CMSNS [1] especially designed for SNS environments. Using CMSNS, a developer can easily build an SNS because CMSNS provides high-level communication functionalities such as user management and content management.…”

Section: Introductionmentioning

confidence: 99%

An Enhanced File Transfer Mechanism Using an Additional Blocking Communication Channel and Thread for IoT Environments

Moon

2019

Sensors

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In this paper, we propose an enhanced file transfer mechanism for a communication framework (CM) for Internet of Things (IoT) applications. Our previous file transfer method uses a basic non-blocking communication channel and thread for the CM (non-blocking method), but this method has a cost of adding additional bytes to each original file block. Therefore, it is not suitable for the transfer of large-sized files. Other existing file transfer methods use a separate channel to transfer large-sized files. However, the creation of a separate channel increases the total transmission delay as the transfer frequency increases. The proposed method uses a dedicated blocking communication channel in a separate thread (blocking method). The blocking method uses a separate channel and thread which are dedicated to transferring file blocks. As it creates the separate channel in advance before the file transfer task, the proposed method does not have an additional channel creation cost at the moment of the file transfer. Through file transfer experiments, the blocking method showed a shorter file transfer time than the non-blocking method, and the transmission delay was increased as the file size grew. By supporting both non-blocking and blocking methods, an application can flexibly select the desirable method according to its requirement. If the application requires the transfer of small-sized files infrequently, it can use the non-blocking method. If the application needs to transfer small-sized or large-sized files frequently, a good alternative is to use the blocking method.

“…CM [2], [3] is a communication framework for developing distributed applications. Application developers can use the Application Programming Interfaces (APIs) and configuration files provided by CM to easily implement various communication functionalities with which CM nodes (applications that use CM's communication services) can interact with each other.…”

Section: Communication Framework (Cm)mentioning

confidence: 99%

Directly and Indirectly Synchronous Communication Mechanisms for Client-Server Systems Using Event-Based Asynchronous Communication Framework

2019

IEEE Access

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In this paper, we propose a synchronous communication mechanism that can be used with asynchronous communication in an event-based communication framework (CM). The proposed synchronous communication mechanism supports directly synchronous communication between client and server, indirectly synchronous communication between two clients through server mediation, and indirectly one-to-many synchronous communication with multiple clients. In order to support synchronous communication, the CM uses the synchronization mechanism between the main thread and the processing thread while maintaining the multi-thread structure. The application can utilize both the asynchronous and the synchronous communication service of the CM together according to its requirements. For performance analysis, we compared the CM synchronous and asynchronous communication methods with qualitative and quantitative experiments, respectively. Through qualitative analysis, developing applications using synchronous services can more intuitively design application logic than asynchronous services. From the quantitative experiment, we also verified that the response delay time in the synchronous method is shorter than that in the asynchronous method although the difference in the response delay is not large.INDEX TERMS Asynchronous communication, client-server system, event-based communication framework, synchronous communication, thread synchronization. methods [7]-[9]. Even though there are researches supporting both the synchronous and asynchronous methods, they can be used only in limited situations [10]-[12], or it is not clearly described [13]- [16]. The communication method used by the communication middleware is determined not by the application requirements but by the communication channel management method or the type of the service in the middleware. Therefore, when the application selects middleware service, its communication method is also fixed. For example, as the communication middleware (CM) [2], [3] that is our previous work was developed as an event-based asynchronous communication framework, all communication services are supported asynchronously. However, because all kinds of services can be performed synchronously and asynchronously, they could become more flexible services if applications can choose one according to their requirements.In this paper, we propose a significantly extended version of CM that supports both synchronous and asynchronous communication methods [17]. We introduce the communication service provided by CM to application and eventbased asynchronous communication structure using multiple threads. In particular, we discuss not only the asynchronous communication method that was previously supported in CM, but also the one-to-one directly synchronous communication with the server, the one-to-one indirectly synchronous communication with the client, and the one-to-many indirectly synchronous communication method with multiple clients. To support the asynchronous communication, CM separates the main thread that ...