Fast Recovery Scheme Research Articles

Software and hardware realizations for different designs of chaos-based secret image sharing systems

Secret image sharing (SIS) conveys a secret image to mutually suspicious receivers by sending meaningless shares to the participants, and all shares must be present to recover the secret. This paper proposes and compares three systems for secret sharing, where a visual cryptography system is designed with a fast recovery scheme as the backbone for all systems. Then, an SIS system is introduced for sharing any type of image, where it improves security using the Lorenz chaotic system as the source of randomness and the generalized Arnold transform as a permutation module. The second SIS system further enhances security and robustness by utilizing SHA-256 and RSA cryptosystem. The presented architectures are implemented on a field programmable gate array (FPGA) to enhance computational efficiency and facilitate real-time processing. Detailed experimental results and comparisons between the software and hardware realizations are presented. Security analysis and comparisons with related literature are also introduced with good results, including statistical tests, differential attack measures, robustness tests against noise and crop attacks, key sensitivity tests, and performance analysis.

Link Recovery Scheme for Multi-Point mmWave Communications

Directional transmission in millimeter wave (mmWave) communications results in prolonged access times. This is attributed to the increased number of conducted measurements to determine optimum beam directions at the mobile station (MS) and base station (BS) that return the highest received signal levels. Additionally, once these beams are determined and links are established for data-planes, then blockage effects and outages make these links more vulnerable to link failures, resulting in communications drops. Hence, dynamic and fast recovery schemes are required to maintain communications sessions following the beam access stage. In this paper, a novel recovery access scheme is proposed for multi-point mmWave communications based on fog access points (AP). Namely, the scheme leverages diversity and network coding techniques to achieve near-instantaneous recovery times, without the need for beam scanning. The scheme features near-instantaneous data recovery times and efficient power consumption as compared to traditional recovery methods.

On reliability improvement of Software-Defined Networks

In Software-Defined Networks (SDNs) the role of the centralized controller is crucial, and thus it becomes a single point of failure. In this work, a distributed controller architecture is explored as a possible solution to improve fault tolerance. A network partitioning strategy, with small subnetworks, each with its own Master controller, is combined with the use of Slave controllers for recovery aims. A novel formula is proposed to calculate the reliability rate of each subnetwork, based on the load and considering the number and degree of the nodes as well as the loss rate of the links. The reliability rates are shared among the controllers through a newly-designed East/West bound interface, to select the coordinator for the whole network. This proposed method is called “Reliable Distributed SDN (RDSDN).” In RDSDN, the failure of controllers is detected by the coordinator that may undertake a fast recovery scheme to replace them. The numerical results prove performance improvement achievable with the adoption of the RDSDN and show that this approach performs better regarding failure recovery compared to methods used in related research.

Exploiting Compression-Induced Internal Fragmentation for Power-Off Recovery in SSD

Recovery from sudden power-off (SPO) is one of the primary concerns among practitioners which bars the quick and wide deployment of flash storage devices. In this work, we propose Metadata Embedded Write (MEW), a novel scheme for handling the sudden power-off recovery in modern flash storage devices. Given that a large fraction of commercial SSDs employ compression technology, MEW exploits the compression-induced internal fragmentation in the data area to store rich metadata for fast and complete recovery. MEW consists of (i) a metadata embedding scheme to harbor SSD metadata in a physical page together with multiple compressed logical pages, (ii) an allocation chain based fast recovery scheme, and (iii) a light-weight metadata logging scheme which enables MEW to maintain the metadata for incompressible data, too. We performed extensive experiments to examine the performance of MEW. The performance overhead of MEW is 3 percent in the worst case, in terms of the write amplification factor, compared to the pure compression-based FTL that does not have any recovery scheme.

Maintaining Data Consistency in Structured P2P Systems

A fundamental challenge of supporting mutable data replication in a Peer-to-Peer (P2P) system is to efficiently maintain consistency. This paper presents a framework for Balanced Consistency Maintenance (BCoM) in structured P2P systems with heterogeneous node capabilities and various workload patterns. Replica nodes of each object are organized into a tree structure for disseminating updates, and a sliding window update protocol is developed for consistency maintenance. We present an analytical model to optimize the window size according to the dynamic network conditions, workload patterns and resource limits. In this way, BCoM balances the consistency strictness, object availability for updates, and update propagation performance for various application requirements. On top of the dissemination tree, two enhancements are proposed: (1) a fast recovery scheme to strengthen the robustness against node and link failures, and (2) a node migration policy to remove and prevent bottlenecks allowing more efficient update delivery. Simulations are conducted using P2PSim to evaluate BCoM in comparison to SCOPE [1]. The experimental results demonstrate that BCoM outperforms SCOPE with lower discard rates. BCoM achieves a discard rate as low as 5 percent in most cases while SCOPE has almost 100 percent discard rate.

Fast IP Network Recovery using MRC

Internet takes vital role in our communications infrastructure, due to slow convergence of routing protocols after network failure become a budding problem. To assure fast recovery scheme from link and node failure in networks, we present a new recovery scheme called Multiple Routing Configuration (MRC). Our anticipated scheme guarantees recovery in all single failure scenarios, using a mechanism to handle both link and node failures, and without knowing the root cause of the failure. MRC is strictly connectionless, and assumes only destination based hop-by-hop forwarding. MRC is based on keeping additional routing information in the routers, and allows packet forwarding to continue on an alternative output link immediately after the detection of a failure. In this paper we present MRC, and analyze its performance with respect to load distribution after a failure. We also show how an estimate of the traffic demands in the network can be used to improve the distribution of the recovered traffic, and thus reduce the chances of congestion when MRC is used..

LIB: A Last-In-Backup Based Fast Recovery Scheme for Ring-Based Industrial Networks

Ring-based industrial networks must possess a fast recovery algorithm when either the switch node or link is faulty. This work presents a simple yet extremely fast recovery algorithm based on the last-in-backup (LIB) concept, in which the final link added to the ring is the backup link. Analysis results indicate the proposed LIB algorithm performs significantly better than the MRP protocol developed in the latest version of the IEC 62439 standard. The proposed LIB algorithm is implemented in industrial Ethernet switches as well. Our results further demonstrate that the proposed recovery algorithm is extremely feasible with a link-down recovery time of 5.5 ms for 50 switches and 6.5ms for 250 switches.

Fast retransmit and fast recovery schemes of transport protocols: A survey and taxonomy

Although there are two standard transport protocols, TCP and UDP, offering services in the Internet, the majority of the traffic over the Internet is TCP-based. TCP-based applications can react to packet losses; however, many performance problems have been recently observed in the Internet. To resolve these problems, several new TCP fast retransmit and fast recovery algorithms have been proposed. This article surveys state-of-the-art fast retransmit and fast recovery mechanisms of TCP to address the lost packet problem, and presents a description of some useful algorithms, design issues, advantages, and disadvantages. The objective of this article is fourfold: to provide an introduction to TCP protocol; to discuss problems degrading TCP retransmission performance in the present-day Internet; to describe some proposed transport protocols that solve a number of throughput issues; and finally, to gain new insight into these protocols and thereby suggest avenues for future research. Based on our taxonomy, existing fast retransmit and fast recovery schemes of transport protocols are described in this survey.