Proposed L-Shape Pattern on UFS ACM For Risk Analysis

Server is a computer system that provides the kind of service in a computer network. One of the functions of the server is as data storage. Computers servers with high availability values are generally referred to as High Availability (HA) Server. HA enables a server can be operational in a sustainable manner for long periods of time. Now, HA has been combined with a cluster technique known as High Availability Clusters or failover cluster. In this research the author intends to apply, analyze, and implement a network file server that has a high availability of service. Researchers used a pacemaker as cluster resource management, Corosync as cluster messaging service and DRBD for the synchronization of data if a failover occurs and measured network performer cluster file system that does have a high availability service. The result is a network file system or the availability of the cluster has a value of 99.998% availability, which means it has a High Availability. The server network file system failover cluster meets the conditions, which, if the primary server (master) dies it will be replaced by a slave server.

LofoSwitch: An online policy for concerted server and disk power control in content distribution networks

The performance of signaling protocols in circuit and packet switching networks is a significant parameter to evaluate the performance of any telecom operator. Today, users demand continuous high data rate, service availability, network reliability, mobility, QoS and minimum service initialization time. IP Multimedia Subsystem (IMS) standardized Session Initiation Protocol (SIP), which categorize as a signaling protocol for management and maintenance of new multimedia IP-based services. Session setup time for the interactive and real-time application has become major QoS parameter to assess the performance of these applications. In the context of this communication application, in this paper, we analyze the performance of session setup time of SIP protocol over IMS network with different access networks (GSM, WLAN and PSTN). We measure and compare mean delay of each SIP message during session setup over these access networks. We also measure the mean delay with respect to distance of nodes in the network. Our results show that SIP message size, processing, transmission, queuing delay, transition from packet to switched network, node mobility and wireless channel have a consequence on the reliability, performance and efficiency of the protocol.

Though security measurement in cloud has become more mature and self-determining in last few years, rather than being solely dependent on vendors for trusting the cloud service, trust management is still a challenging issue for cloud researchers. Instead of having some amazing qualities like virtualization potential, high storage capacity, multi tenancy , high service availability - the only obstacle to adapt the cloud technology in a huge scale, is till now its security and trust issue. Trust being a qualitative factor can be established and determined independently and several algorithms are there to establish trust in a cloud system. This paper focuses on measuring the strength of cloud security by establishing trust, using some measurement index and with the help of some known parameters.

Cloud computing has already been adopted in a broad range of application domains and has become an established building block in IT landscapes. During the process of cloud middleware development, the companies have focused mainly on the high availability of data and end-user services, but unfortunately neglected the availability of middleware components. Therefore failures of the middleware components itself usually leads to a partial or even total blackout of the cloud. In this paper, we present the design and implementation of a novel scalable and highly available multi-master pattern for cloud middlewares. In contrast to existing Infrastructure-as-a-Service cloud management frameworks, which are usually designed in a centralized tree topology composed in a three-tiered master worker architecture, we introduce a concept for a multi tree with all tree roots connected in a fully connected mesh topology. In this architecture user requests are load balanced over multiple failover servers. Furthermore, our concept includes an automatic self-healing mechanism for worker nodes of each tree.

The goal of Linux Virtual Server (LVS) is to provide a basic framework to build highly available and scalable network services such as Radius authentication and accounting in our implementation. Scalability is achieved by transparently inserting or removing a node in the cluster, and high availability is supported by detecting node or daemon failures and reconfiguring the system appropriately. This article, rather than proposing a new cluster technique, illustrates the basic concept of LVS, an implementation of LVS-based highly-available Radius server, and the performance testing and analysis of the whole system by a testing software named testrad developed by us. Through the benchmarks, we can conclude that the performance of the system can linearly increase along with the increasing number of the real servers before the director gets fully-loaded. Thus, it can provide high availability and scalability for network services. (4 pages)

Grids are becoming a mission-critical component in research and industry. The services they provide are thus required to be highly available, contributing to the vision of the grid as a dependable virtual computer of infinite power. However, building highly available services in grid is particularly difficult due to the unique characteristics of the grid environment. We believe that high availability functionality should itself be provided as a service, which can be used by transparently decorating, but not changing, the original services, thus making them highly available. In this work we highlight the major challenges and describe our initial experience in building such a generic high availability service in the context of the Condor system

Satellite communications are expected to collaborate with 5G techniques in the future. In this paper, a detector based on the minimum mean square error (MMSE) criterion is designed at the receiver of a LEO satellite system to cancel co-channel interference (CCI) in a predetermined order successively, which is called ordered successive interference cancellation (OSIC). In order to make the detector have stronger ability to mitigate interference, low density parity check (LDPC) coding and soft demodulation schemes are applied with the OSIC jointly to improve our proposed MMSE-OSIC detector's performance. In the simulation analysis, we present the bit error rate (BER) performance of our proposed detector in an AWGN channel. Numerical results show that compared to the results of the conventional detection in existing literatures, the MMSE-OSIC detector can reduce the BERs for fixed signal-to-noise ratio (SNR) values. It means our proposed detector can be employed at the receiver with high service availability and reliability guaranteed.

Mobile Network Operator (MNO)s avail the benefit of providing an isolated service with the network slice in a variety of forms like enhanced Mobile Broadband (eMBB), ultra Reliable Low Latency Communications (uRLLC), and massive Machine Type Communications (mMTC). However, they face challenges in handling situations of overload, congestion, and scaling with the arrival of unexpected control plane User Service Requests (USRs) leading to the dropping of USRs, and hence disturbing the slice’s High Availability (HA). This paper presents a novel High Availability supportive self Reliant NEtwork Slicing System (HARNESS) for 5G Core, powered by intelligent and autonomous Self Organizing Network (SON) paradigm. In HARNESS, we propose algorithms to intelligently schedule and serve the significant portion of control plane USRs for both delay tolerant and delay sensitive slices, to ensure their uninterrupted HA service provision. Along with efficient resource utilization, the HARNESS shows improvements over the traditional HA provisioning methods, in preventing the occluding of crucial control plane USRs by 60% and reducing the average response time for these USRs by 50%. We developed the HARNESS framework in a 5G test-bed system using eXpress Data Path (XDP) and extended Berkeley Packet Filter (eBPF) mechanism for coherent and optimized end-to-end working of it. With this additional gear, HARNESS productively contributes to achieving 3.2% better slice service HA in the minimal two nodes active/active cluster configuration.

A very high service availability is important for the operator and for the user of road tunnels, too. The service availability of a structure is directly related to its quality. The earlier quality assurance measures are being considered during the life cycle, the better a structure of high quality can be guaranteed. Problems which occur during the operation period of a structure often result from design errors or from inadequate realisation during the construction phase. They may also occur as a result of wrongly planned maintenance and refurbishment works. Thus, the transfer of specific data, information and experiences through the whole life cycle is very important. In this context methods of facility management can provide efficient assistance when they have already been used throughout all three classic phases of a structure‘s life cycle - planning, construction and operation. Finally the tunnel drainage system of German road tunnels is considered as an example as practical application possibility.

Calculations of service availability of a high-availability (HA) cluster are usually based on the assumption of load- independent machine availabilities. In this paper, we study the issues and show how the service availabilities can be calculated under the assumption that machine availabilities are load dependent. We present a Markov chain analysis to derive the steady-state service availabilities of a load-dependent machine availability HA cluster. We show that with a load-dependent machine availability, the attained service availability is now policy dependent. After formulating the problem as a Markov decision process, we proceed to determine the optimal policy to achieve the maximum service availabilities by using the method of policy iteration. Two greedy assignment algorithms are studied: least load and first derivative length (FDL) based, where least load corresponds to some load balancing algorithms. We carry out the analysis and simulations on two cases of load profiles: In the first profile, a single machine has the capacity to host all services in the HA cluster; in the second profile, a single machine does not have enough capacity to host all services. We show that the service availabilities achieved under the first load profile are the same, whereas the service availabilities achieved under the second load profile are different. Since the service availabilities achieved are different in the second load profile, we proceed to investigate how the distribution of service availabilities across the services can be controlled by adjusting the rewards vector.

Meso-level Comparison of Mental Health Service Availability and Use in Chile and Spain

The operating system’s role is often neglected in the availability analysis of modern, service-oriented applications. The usual argumentation is that the underlying OS seems to be irrelevant in the world of today’s web-centric applications. We propose a framework for construction of “service-oriented operating system” and examine the role it plays in physical and user-perceived service availability by investigating potential abstractions and integration points between service-oriented applications and OS architecture, such as treating OS as a set of collaborating services, introducing standard middleware services as parts of an OS and including support for server consolidation through virtualization. We demonstrate how to address the following dependability attributes at the OS level: service availability (readiness for correct service), service reliability (continuity of correct service), integrity (absence of improper system alterations) and maintainability (ability to undergo modifications and repair). We further argue that availability at the OS level plays the key role in the availability of service-oriented applications and propose an orthogonal OS design methodology suited for that purpose.KeywordsService Level AgreementService AvailabilityVirtual ChannelCorrect ServiceServer ConsolidationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

High enterprise IT service availability is a key success factor throughout many industries. While understanding of the economic importance of availability management is becoming more widespread, the implications for management of Service Level Agreements (SLAs) and thinking about availability risk management are just beginning to unfold. This paper offers a framework within which to think about availability management, highlighting the importance of variance of outage costs. The importance of variance is demonstrated using simulations on existing data sets of revenue data. An important implication is that when outage costs are proportional to outage duration, more but shorter outages should be preferred to fewer but longer, in order to minimize variance. Furthermore, two archetypal cases where the cost of an outage depends non-linearly on its duration are considered. An optimal outage length is derived, and some guidance is also given for its application when the variance of hourly downtime costs is considered. The paper is concluded with a discussion about the feasibility of the method, its practitioner relevance and its implications for SLA management.

For many, the advantages of always-on (AO) are still not clear and the concept can be difficult to understand and distinguish from traditional network connections. How important is the ability to be AO compared to other network characteristics? What will be the quality of the service (speed, availability and reliability) and which services will take full advantage of AO? Is it important to be able to control the information flow? What will be the business model for AO services — would it be cheaper or more expensive than other networks? What are the security and privacy concerns, and are there any social consequences such as less face-to-face contact and user isolation?The paper starts by describing the work done to capture the users' attitudes and expected behaviour towards AO. This includes a review of the initial testing of the AO concept through a number of focus groups and the development of usage scenarios to illustrate the possibilities for AO services. The results from a number of AO user trials are also presented. These user trials were carried out in five different European countries and provide a snapshot of different AO services across Europe. The trials identified a number of technical and operational issues for AO services and the paper makes recommendations for the operation of AO services, and the implications for AO terminals, devices and services. The user trials identified a significant difference between being ‘always-on to a network' and being ‘always-on to a service' — which seems to be a much more compelling proposition for users. This is further explored in this paper with a description of some ongoing research work investigating this issue through the development of a device-unifying service (DUS) which provides users with a single virtual terminal for all of their devices and access to persistent network-based services, which are ‘always-on'.This work was undertaken within EURESCOM, the European Institute for Research and Strategic Studies in Telecommunications, a leading institute for collaborative R&D in telecommunications. It was completed as two separate projects (P1003 ‘Exploiting the always-on concept’, and P1101 ‘The device-unifying service') with different collaborative partners in each.