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In cloud environment, client user credential protection is a critical security capability that is target of adversarial attacks, especially, in cloud file synchronization applications. Among the various adversarial attacks, MITC (Man in the Cloud) attack on commercial cloud storage applications has emerged as a critical threat because it is easy to launch and hard to detect. In this paper, we propose...
A geographically isolated disaster-tolerant system for Distributed File System (DFS) is essential for its enhancement in data security. However, the plain disaster tolerant model performs poor quality while a switch happens in hot-backup. In this study, we proposed a Direct Data Fetch (DDF) technology for the hybrid model. The DDF can fetch data directly from the data chunk server while the main server...
TCP incast problem has become a severe problem in datacenters due to the catastrophic collapse of goodput at the receiver side. Many solutions have been proposed, however, none of them solved it fundamentally. In this paper, we take a deep dive into the causes of incast problem, and find out that the root cause of TCP incast is the droptails induced by TCP congestion control algorithm based on packet...
The use of real-time operating systems for small micro controllers creates two major problems. The former refers to the way interruptions must be handled so that deadlines can be complied with. The latter regards the fact that there may be tasks that will not synchronize with events generated by multiple objects such as semaphores, mutexes, messages or interrupts. The present article discusses several...
Data center networks widely uses TCP for communication between the servers as it provides reliability and congestion control. However, TCP does not work well for certain type of communication patterns. One such a pattern is barrier synchronized many to one communication. During this type of data transmissions, multiple servers simultaneously transmits data to a single client and also the client cannot...
Computation is increasingly moving to the data enter. Thus, the energy used by CPUs in the data centeris gaining importance. The centralization of computation in the data center has also led to much commonality between the applications running there. For example, there are many instances of similar or identical versions of the Apache web server running in a large data center. Many of these applications,...
In high bandwidth and low latency data center networks, when multiple data senders simultaneously communicate with a single receiver, namely in many-to-one communication pattern, it is frequently occurred that the burst data overload the receiver's switch buffers, which leads to TCP throughput collapse. This phenomenon is termed to TCP Incast problem, which has become a new hot research topic in recent...
TCP incast problem has become a severe problem in datacenters due to the catastrophic collapse of goodput at the receiver side. Many solutions have been proposed, however, none of them solved it fundamentally. In this paper, we take a deep dive into the causes of incast problem, and find out that the root cause of TCP incast is the droptails induced by TCP congestion control algorithm based on packet...
As application requirements increase in quantity and popularity, big data storage is becoming an important technology which data centers and Internet companies depend on. The cluster file system with centralized metadata management often encounters planned or unplanned downtime which requires higher reliability for metadata service. Current paradigms use the backup server to take over as the primary...
Time synchronization is a key requirement in many automation systems. There are currently two predominant technologies for time synchronization in automation systems: SNTP (Simple Network Time Protocol) and PTP (Precision Time Protocol). PTP is the preferred technology and has several advantages over SNTP including far better accuracy in most if not all situations. However, legacy systems in many...
With the emergence of multimode terminals and the deployment of multiple access networks, users are expecting ubiquitous and seamless connectivity across heterogeneous networks when using IP-based applications. For bandwidth intensive IP-based application such as Internet Protocol Television (IPTV), the multimedia contents are usually transmitted via multicast delivery for reason of efficiency. However,...
In IPTV networks, channel change latency is a major concern for achieving the desired quality of experience at the subscribers. Since IPTV connections are established over limited capacity links, the number of channels available to each subscriber's use, at any given point in time, is strictly limited. As a direct consequence of this limitation, channel change requests need to go through the IP infrastructure,...
TCP Incast, also known as TCP throughput collapse, is a term used to describe a link capacity under-utilization phenomenon in certain many-to-one communication patterns, typically in many datacenter applications. The main root cause of TCP Incast analyzed by prior works is attributed to packet drops at the congestion switch that result in TCP timeout. Congestion control algorithms have been developed...
This paper describes a method of digital audio public address (PA) system based on Ethernet. The main framework of the system is proposed and the core techniques are analyzed. The hardware design of network audio devices and software design are described in details in this paper. CYCLONE II EP2C5FA484 programmable FPGA chip and audio codec VS1003 are proposed in the network audio terminal design,...
This paper analyzes the performance of Ethernet layer congestion control mechanism Quantized Congestion Notification (QCN) during data access from clustered servers in data centers. We analyze the reasons why QCN does not perform adequately in these situations and propose several modifications to the protocol to improve its performance in these scenarios. We trace the causes of QCN performance degradation...
The current status and the disaster risks the information systems faced are analysed in this paper. Combined with domestic and international status of technological developments in the field of information systems disaster recovery, disaster recovery needs and disaster recovery objectives, the primary and disaster recovery system construction framework based on the database replication techniques...
This paper proposes a media synchronization method for real-time group communication within a multiple device environment. The method controls the output time of each media unit received at multiple devices and synchronizes them, even if the arrival time of the media unit temporarily fluctuates. This fluctuation is caused by variation in bandwidth and the network delay between different access networks...
This paper presents architecture for accelerating message switch and synchronization performed in a message passing library developed on Maestro3 cluster network. Maestro3 is a high-performance cluster network that has the optimized data link layer and the capability of dynamic offload. We propose the dedicated hardware for further improvement of communication performance. In this paper, detailed...
Key technologies of disaster tolerant intelligent network are briefly introduced at first. After the hot-standby disaster tolerant IN architecture is analyzed, a load-sharing mode is proposed which has no downtime during switchover. By constructing the availability models of local clustered subsystem and the load-sharing disaster tolerant IN system based on birth-death process, it is proved that the...
In distributed file systems, a need may arise for relocation of the file system to a different server. This is one of the fundamental mechanisms for ensuring file service availability for the geographically distributed clients. However, migration or replication in many such systems requires that the client or client side daemons take active measures for accessing the alternate servers, thus compromising...
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