scholarly journals Upper Bound on Blocking Probability for Vertically Stacked Optical Banyan Networks with Link Failures and Given Crosstalk Constraint

2009 ◽  
Vol 1 (3) ◽  
pp. 484-494
Author(s):  
M. R. Khandker ◽  
B. Sultana
Keyword(s):  
Upper Bound ◽  
Optical Switching ◽  
Network Performance ◽  
Blocking Probability ◽  
Hardware Cost ◽  
Link Failures ◽  
Banyan Network ◽  
Multiple Copies ◽  
Simulation Results ◽  
Banyan Networks

Vertical stacking of multiple copies of an optical banyan network is a novel scheme for building nonblocking optical switching networks. The resulting network, namely vertically stacked optical banyan (VSOB) network, preserves all the properties of the banyan network, but increases the hardware cost significantly under first order crosstalk-free constraint. However, stringent crosstalk constraint may not always be necessary. Considering the fact that some designer may want to compromise the blocking probability and crosstalk constraint to a certain degree with the hardware cost, blocking behaviour of such VSOB networks have been analyzed to studying network performance and finding a graceful compromise between hardware costs and blocking probability under or without crosstalk constraint. In this paper, we present the simulation results for upper bound on blocking probability of VSOB networks with link failures and given degree of crosstalk constraint. We show how crosstalk adds a new dimension to the performance analysis on a VSOB networks. The simulation results presented in this paper can guide network designer in finding the trade-off among the blocking probability, the degree of crosstalk and the hardware cost in terms of vertical copies of banyan network in the presence of link failures.Keywords: Banyan networks; Blocking probability; Vertical stacking; Link-failures; Crosstalk.© 2009 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.DOI: 10.3329/jsr.v1i3.1191       J. Sci. Res. 1 (3), 484-494 (2009)

On Number of Planes of Rearrangeably Nonblocking Optical Banyan Networks with Link Failures

2008 ◽  
Vol 1 (1) ◽  
pp. 43-54
Author(s):  
Basra Sultana ◽  
Mamun-ur-Rashid Khandker
Keyword(s):  
Optical Switching ◽  
Blocking Probability ◽  
Link Failure ◽  
Link Failures ◽  
Small Depth ◽  
Internal Link ◽  
Banyan Network ◽  
Minimum Number ◽  
Switch Design ◽  
Banyan Networks

Vertically stacked optical banyan (VSOB) networks are attractive for serving as optical switching systems due to the desirable properties (such as the small depth and self-routing capability) of banyan network structures. Although banyan-type networks result in severe blocking and crosstalk, both these problems can be minimized by using sufficient number of banyan planes in the VSOB network structure. The number of banyan planes is minimum for rearrangeably nonblocking and maximum for strictly nonblocking structure. Both results are available for VSOB networks when there exist no internal link-failures. Since the issue of link-failure is unavoidable, we intend to find the minimum number of planes required to make a VSOB network nonblocking when some links are broken or failed in the structure. This paper presents the approximate number of planes required to make a VSOB networks rearrangeably nonblocking allowing link-failures. We also show an interesting behavior of the  blocking  probability of a faulty VSOB networks that the blocking probability may not  always  increase monotonously with  the  increase  of  link-failures; blocking probability  decreases  for  certain range of  link-failures, and then increases again. We believe that such fluctuating behavior of blocking probability with the increase of link failure probability deserves special attention in switch design.  Keywords: Banyan networks; Blocking probability; Switching networks; Vertical stacking; Link-failures. © 2009 JSR Publications. ISSN: 2070-0237(Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v1i1.1070

scholarly journals MedShard: Electronic Health Record Sharing Using Blockchain Sharding

2021 ◽  
Vol 13 (11) ◽  
pp. 5889
Author(s):  
Faiza Hashim ◽  
Khaled Shuaib ◽  
Farag Sallabi
Keyword(s):  
Healthcare System ◽  
Small Groups ◽  
Network Performance ◽  
Communication Overhead ◽  
Privacy And Security ◽  
Health Records ◽  
Medical Practitioners ◽  
Blockchain Technology ◽  
Simulation Results ◽  
Electronic Health

Electronic health records (EHRs) are important assets of the healthcare system and should be shared among medical practitioners to improve the accuracy and efficiency of diagnosis. Blockchain technology has been investigated and adopted in healthcare as a solution for EHR sharing while preserving privacy and security. Blockchain can revolutionize the healthcare system by providing a decentralized, distributed, immutable, and secure architecture. However, scalability has always been a bottleneck in blockchain networks due to the consensus mechanism and ledger replication to all network participants. Sharding helps address this issue by artificially partitioning the network into small groups termed shards and processing transactions parallelly while running consensus within each shard with a subset of blockchain nodes. Although this technique helps resolve issues related to scalability, cross-shard communication overhead can degrade network performance. This study proposes a transaction-based sharding technique wherein shards are formed on the basis of a patient’s previously visited health entities. Simulation results show that the proposed technique outperforms standard-based healthcare blockchain techniques in terms of the number of appointments processed, consensus latency, and throughput. The proposed technique eliminates cross-shard communication by forming complete shards based on “the need to participate” nodes per patient.

Limitation of Erlang B Traffic Model in Elastic Optical Network for Blocking Probability Estimation

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Ujjwal ◽  
Jaisingh Thangaraj
Keyword(s):  
Blocking Probability ◽  
Optical Network ◽  
Constant Load ◽  
Traffic Model ◽  
Service Rate ◽  
Service Provisioning ◽  
Connection Request ◽  
Elastic Optical Network ◽  
Simulation Results ◽  
Single Path

Abstract In this paper, an algorithm for multipath connection provisioning in elastic optical network (EON) has been proposed. Initially, the algorithm prefers the single-path routing for service provisioning. But when single-path routing is not adequate to serve a dynamic connection, the algorithm switches to the connection request fragmentation. Its computation is based on the parameters such as capacity_constant and capacity_allowed to fragment the connection request on disjoint paths. Simulation results clearly state that the proposed algorithm performs well in service provisioning as compared to the traditional single-path routing algorithms and improves the average network throughput. Thereafter, we have investigated the limitation of Erlang B traffic model in EON for calculation of link blocking probability using routing and spectrum assignment (RSA) algorithm. It is verified by the following two ways: (i) effect on the blocking probability in case of constant load and (ii) effect of slot width on the blocking probability. Our simulation results indicate that in EON due to dynamic RSA, blocking probability is not constant in case of proportionate varying of call arrival and service rate giving constant load and blocking probability depends on the number of slots per link, but in Erlang B traffic model blocking probability is always constant in case of constant load and it considers wavelength per link instead of slots per link. This is attributed to the fact that Erlang B traffic model fails to calculate blocking probability accurately in EON. We have computed the carried traffic on 14 nodes, 21-link National Science Foundation Network (NSFNET) topology.

scholarly journals Relationship-Oriented Software Defined AS-Level Fast Rerouting for Multiple Link Failures

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Chunxiu Li ◽  
Xin Li ◽  
Ke Li ◽  
Jiafu Huang ◽  
Zhansheng Feng ◽  
...  
Keyword(s):  
Distributed Control ◽  
Large Scale ◽  
Network Performance ◽  
Failure Recovery ◽  
Internet Routing ◽  
Link Failures ◽  
Significant Control ◽  
Control Overhead ◽  
Fast Reroute ◽  
Multiple Link Failures

Large-scale deployments of mission-critical services have led to stringent demands on Internet routing, but frequently occurring network failures can dramatically degrade the network performance. However, Border Gateway Protocol (BGP) can not react quickly to recover from them. Although extensive research has been conducted to deal with the problem, the multiple failure scenarios have never been properly addressed due to the limit of distributed control plane. In this paper, we propose a local fast reroute approach to effectively recover from multiple link failures in one administrative domain. The principle of Software Defined Networking (SDN) is used to achieve the software defined AS-level fast rerouting. Considering AS relationships, efficient algorithms are proposed to automatically and dynamically find protection paths for multiple link failures; then OpenFlow forwarding rules are installed on routers to provide data forwarding continuity. Our approach is able to ensure applicability to ASes with flexibility and adaptability to multiple link failures, contributing toward improving the network performance. Through experimental results, we show that our proposal provides effective failure recovery and does not introduce significant control overhead to the network.

Research on Route Protocol and Architecture for WSN Based on IPv6

2012 ◽  
Vol 616-618 ◽  
pp. 2233-2238 ◽  
Author(s):  
Rui Ting Lu ◽  
Xiang Zhen Li ◽  
Jia Hui Wang ◽  
Feng Jie Sun
Keyword(s):  
Load Balancing ◽  
Routing Protocol ◽  
Network Performance ◽  
Experimental Result ◽  
Routing Overhead ◽  
On Demand ◽  
End To End Delay ◽  
Simulation Results ◽  
Demand Routing ◽  
Route Protocol

WSN based on IPv6 is a new network integrated IPv6 and WSN. The related technologies of WSN based on IPv6 was researched, and an architecture of WSN based on IPv6 was proposed according to 6LoWPAN protocol in this article. Efficient and stable route protocol is a main focus to ensure network performance. Refer to on-demand routing protocol DSR, a Load-Balancing route protocol for WSN based on IPv6 was designed. An implementation of this protocol was programmed in NS2, and its simulation results were analyzed. The experimental result shows that this protocol could effectively reduce end-to-end delay and routing overhead, improving the network performance.

Analyzing the Effect of Node Density on the Performance of the LAR-1P Algorithm

2012 ◽  
Vol 7 (2) ◽  
pp. 16-29
Author(s):  
Hussein Al-Bahadili ◽  
Ali Maqousi ◽  
Reyadh S. Naoum
Keyword(s):  
Network Performance ◽  
Ad Hoc ◽  
High Density ◽  
Low Density ◽  
Probabilistic Algorithms ◽  
Excellent Performance ◽  
Node Density ◽  
Simulation Results ◽  
Mobile Ad Hoc ◽  
Hoc Networks

The location-aided routing scheme 1 (LAR-1) and probabilistic algorithms are combined together into a new algorithm for route discovery in mobile ad hoc networks (MANETs) called LAR-1P. Simulation results demonstrated that the LAR-1P algorithm reduces the number of retransmissions as compared to LAR-1 without sacrificing network reachability. Furthermore, on a sub-network (zone) scale, the algorithm provides an excellent performance in high-density zones, while in low-density zones; it preserves the performance of LAR-1. This paper provides a detailed analysis of the performance of the LAR-1P algorithm through various simulations, where the actual numerical values for the number of retransmissions and reachability in high- and low-density zones were computed to demonstrate the effectiveness and significance of the algorithm and how it provides better performance than LAR-1 in high-density zones. In addition, the effect of the total number of nodes on the average network performance is also investigated.

scholarly journals Spontaneous Ad Hoc Mobile Cloud Computing Network

2014 ◽  
Vol 2014 ◽  
pp. 1-19 ◽  
Author(s):  
Raquel Lacuesta ◽  
Jaime Lloret ◽  
Sandra Sendra ◽  
Lourdes Peñalver
Keyword(s):  
Cloud Computing ◽  
Information Processing ◽  
Network Performance ◽  
Mobile Cloud Computing ◽  
Ad Hoc ◽  
Smart Devices ◽  
Mobile Cloud ◽  
Good Efficiency ◽  
Simulation Results ◽  
Personal Devices

Cloud computing helps users and companies to share computing resources instead of having local servers or personal devices to handle the applications. Smart devices are becoming one of the main information processing devices. Their computing features are reaching levels that let them create a mobile cloud computing network. But sometimes they are not able to create it and collaborate actively in the cloud because it is difficult for them to build easily a spontaneous network and configure its parameters. For this reason, in this paper, we are going to present the design and deployment of a spontaneous ad hoc mobile cloud computing network. In order to perform it, we have developed a trusted algorithm that is able to manage the activity of the nodes when they join and leave the network. The paper shows the network procedures and classes that have been designed. Our simulation results using Castalia show that our proposal presents a good efficiency and network performance even by using high number of nodes.

scholarly journals CELLULAR LEARNING AUTOMATA BASED DYNAMIC CHANNEL ASSIGNMENT ALGORITHMS

2009 ◽  
Vol 08 (03) ◽  
pp. 287-314 ◽  
Author(s):  
HAMID BEIGY ◽  
M. R. MEYBODI
Keyword(s):  
Channel Assignment ◽  
Blocking Probability ◽  
Learning Automata ◽  
Dynamic Channel Assignment ◽  
Additional Information ◽  
The Third ◽  
The Status ◽  
Dynamic Channel ◽  
Simulation Results ◽  
Cellular Learning Automata

A solution to channel assignment problem in cellular networks is self-organizing channel assignment algorithm with distributed control. In this paper, we propose three cellular learning automata based dynamic channel assignment algorithms. In the first two algorithms, no information about the status of channels in the whole network will be used by cells for channel assignment whereas in the third algorithm, the additional information regarding status of channels may be gathered and then used by cells in order to allocate channels. The simulation results show that by using the proposed channel assignment algorithms the micro-cellular network can self-organize itself. The simulation results also show that the additional information used by the third algorithm help the cellular learning automata to find an assignment which results in lower blocking probability of calls for the network.

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