In classical monolithic router architecture, the Border Gateway Protocol (BGP) engine is implemented as a multiprocess centralized function within the controller entity. This architecture does not scale well and its p...
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ISBN:
(纸本)9781424444885
In classical monolithic router architecture, the Border Gateway Protocol (BGP) engine is implemented as a multiprocess centralized function within the controller entity. This architecture does not scale well and its performance decreases when the load increases, forcing multiple processes to compete for the same controller processor. In addition only a limited number of peer connections can be handled. In this paper, we propose a novel scalable distributed architecture for the BGP engine without modifying the core of the BGP protocol as defined in RFC 4271. The proposed architecture is designed according to the "Master-Slave" task separation along with the replication of the Routing Information Base (RIB) on multiple controller cards. In addition, we design a new consistency algorithm for the RIB replication. Simulations show an acceptable trade-off between the scalability to a large number of peer sessions and the overhead caused by the communication latency. Furthermore, simulations show that the proposed architecture handily outperforms the actual BGP processing capacity. Accordingly, we conclude that our approach increases considerably both scalability and reliability thanks to the replication of the RIB.
In this paper, we propose, present and analyze the behavior and the performance of a reconfigurable algorithm for shared objects consistency management in distributed systems. Object sharing allows nodes to concurrent...
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ISBN:
(纸本)0769524869
In this paper, we propose, present and analyze the behavior and the performance of a reconfigurable algorithm for shared objects consistency management in distributed systems. Object sharing allows nodes to concurrently/parallel access a same set of replicated objects. However, it is necessary that the nodes know when and how to do these accesses, avoiding inconsistencies in the objects state. The RCA (Reconfigurable consistency algorithm) is a reconfigurable algorithm that guarantees the objects consistency. This algorithm modifies its behavior and structure according to the changes in the workload and distributed systems parameters. The paper shows that: the use of RCA generates flexibility and improves the performance in 30%, on average.
With the development whereby mobile content distribution systems can manage dynamically changing files, an important issue to be resolved is consistency management, which means the cached replicas on different mobile ...
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ISBN:
(纸本)9781424423736
With the development whereby mobile content distribution systems can manage dynamically changing files, an important issue to be resolved is consistency management, which means the cached replicas on different mobile sites must be updated if the originals change. This paper is to design an integrated consistency-control algorithm for mobile contents delivery network (M-CDN) to enhance the efficient utilization of network resource and support the client mobility. Firstly, by carrying out an analysis of mobile surrogates' characteristics, for a given content which has been changed on its original node, only a limited number of its replicas instead of all replicas are updated. Secondly, if a replica has been selected for update, the latest version will be sent from an algorithm-decided site instead of from its original server. Simulation results show that the proposal outperforms other conventional methods.
Dechter et al. [5] proposed solving the Temporal Constraint Satisfaction Problem (TCSP) by modeling it as a meta-CSP, which is a finite CSP with a unique global constraint. The size of this global constraint is expone...
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Dechter et al. [5] proposed solving the Temporal Constraint Satisfaction Problem (TCSP) by modeling it as a meta-CSP, which is a finite CSP with a unique global constraint. The size of this global constraint is exponential in the number of time points in the original TCSP, and generalized-arc consistency is equivalent to finding the minimal network of the TCSP, which is NP-hard. We introduce AC, an efficient consistency algorithm for filtering the meta-CSP. This algorithm significantly reduces the domains of the variables of the meta-CSP without guaranteeing arc-consistency. We use AC as a preprocessing step to solving the meta-CSP. We show experimentally that it dramatically reduces the size of a meta-CSP and significantly enhances the performance of search for finding the minimal network of the corresponding TCSP.
This paper discusses rule-based reasoning parameter consistency management system based on knowledge in concurrent and corroborative product design using a combination of both mathematical methods and knowledge-based ...
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This paper discusses rule-based reasoning parameter consistency management system based on knowledge in concurrent and corroborative product design using a combination of both mathematical methods and knowledge-based Engineering (KBE) techniques. First, the framework of the parameter consistency management system is developed. Second, a data-mining algorithm known as the fuzzy-rough algorithm is presented for modelling of knowledge-level constraints from numerical simulation. Then, the method of integrated case-based reasoning (CBR) and rule-based reasoning (RBR) with an interval consistency algorithm is adopted to predict the potential conflicts and specify the interval of design parameters. Finally, ontology is used as a communication language between cooperating engineering design teams. The system is demonstrated by the design of a crank connecting link in a V6 engine.
Content delivery network improves end-user performance by replicating Web contents on a group of geographically distributed sites interconnected over the Internet. However, with the development whereby content distrib...
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Content delivery network improves end-user performance by replicating Web contents on a group of geographically distributed sites interconnected over the Internet. However, with the development whereby content distribution systems can manage dynamically changing files, an important issue to be resolved is consistency management, which means the cached replicas on different sites must be updated if the originals change. In this paper, based on the analytical formulation of object freshness, web access distribution and network topology, we derive a novel algorithm as follows: (1) For a given content which has been changed on its original server, only a limited number of its replicas instead of all replicas are updated. (2) After a replica has been selected for update, the latest version will be sent from an algorithm-decided site instead of from its original server. Simulation results verify that the proposed algorithm provides better consistency management than conventional methods with the reduced the old hit ratio and network traffic.
Content Delivery Overlays improves end-user performance by replicating Web contents on a group of geographically distributed sites interconnected over the Internet. However, with the development whereby overlay system...
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ISBN:
(纸本)9781424403523
Content Delivery Overlays improves end-user performance by replicating Web contents on a group of geographically distributed sites interconnected over the Internet. However, with the development whereby overlay systems can manage dynamically changing files, an important issue to be resolved is consistency management, which means the cached replicas on different sites must be updated if the originals change. In this paper, based on the analytical formulation of object freshness, web access distribution and network topology, we derive a novel algorithm as follows: (1) For a given content which has been changed on its original server, only a limited number of its replicas instead of all replicas are updated. (2) After a replica has been selected for update, the latest version will be sent from an algorithm-decided site instead of from its original server. Simulation results verify that the proposed algorithm provides much better consistency management than conventional methods with the reduced the old hit ratio and network traffic.
This paper describes a robust design method using constraint networks. As opposed to the traditional statistical robust methodology, the proposed method gives a valid model to analyze parameter uncertainties so as to ...
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This paper describes a robust design method using constraint networks. As opposed to the traditional statistical robust methodology, the proposed method gives a valid model to analyze parameter uncertainties so as to predict conflicts in concurrent design. The mathematical model, which reflects the requirements of robust design, is given in the paper. A general consistency algorithm is designed using interval arithmetic to refine the intervals. This paper also proves that the consistency algorithm is. arc consistent if the constraint network is integrated. The constraint network uses the consistency algorithm to verify the design process early in the process and to assist the designers in determining design variables to reduce the multidisciplinary iterations in concurrent design. The quantitative effect of downstream constraints can be analyzed before determining design parameters and potential conflicts can be predicted. A layout design example shows the validity of the method.
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