Cache Mapping Research Articles

Improving efficiency of network resources in elastic optical transport network by using in-network cache functions

We developed a network architecture called information-centric elastic optical transport network (i-CEON) that enables efficient content delivery. Increasing the volume of video traffic consumes network resources, so it is necessary to establish optical transport network architectures suitable for content delivery. For this purpose, we extend existing information-centric networking to be applicable to elastic optical networks. The main focus of this paper is presenting the method in i-CEON of optimizing optical-path routing by effectively using an in-network cache function to efficiently accommodate content traffic. This reduces redundant use of network resources. We formulate the joint optimization problem of elastic optical-path routing and content-replication placement as a mixed integer linear programming problem and also develop a heuristic algorithm. We conducted intensive numerical experiments to demonstrate the effectiveness of our method and confirmed that it reduced network cost by 21% and server load by 32%.

Event-triggered model predictive control for switched systems: a memory-based anti-attack strategy

This paper investigates event-triggered model predictive control (MPC) problem for switched systems. In network transmission processes, two problems (including limited resources and denial of service (DoS) attacks) profoundly affect the usability of control systems. Especially, DoS attacks that occur in feedback channel can make the systems open-loop. In this regard, a novel memory-based anti-attack strategy is presented, which is implemented by adding a cache function to network controllers. An event-triggering mechanism is adopted to improve network resource utilisation and reduce the probability of transmission data being attacked. MPC technology is employed for network controllers, which optimises the control input and state by minimising an upper bound of a quadratic cost function. Then, closed-loop switched system is established, and the coupling relationship between switching and attacking is clearly discussed. Based on average dwell time approach, performance is analysed. The co-design of MPC controllers and event-triggering matrices are given by solving linear matrix inequalities (LMIs). Finally, a numerical example is provided to demonstrate the feasibility.

A cache consolidation design of MLC STT-RAM for energy efficiency enhancement on cyber-physical systems

Owing to the energy-constraint nature of cyber-physical systems (CPS), energy efficiency has become a primary design consideration for CPS. On CPS, owing to the high leakage power issue of SRAM, the major portion of its energy consumption comes from static random-access memory (SRAM)-based processors. Recently, with the emerging and rapidly evolving nonvolatile Spin-Transfer Torque RAM (STT-RAM), STT-RAM is expected to replace SRAM within processors for enhancing the energy efficiency with its near-zero leakage power features. The advances in Magnetic Tunneling Junction (MTJ) technology also realize the multi-level cell (MLC) STT-RAM to pack more cells with the same die area for achieving the memory density. However, the write disturbance issue of MLC STT-RAM prevents STT-RAM from properly resolving the energy efficiency of CPS. Although studies have been proposed to alleviate this issue, previous strategies could induce additional management overhead due to the use of counters or lead to frequent swap operations. Such an observation motivates us to propose an effective and simple strategy to combine direct and split cache mapping designs to enhance the energy efficiency of MLC STT-RAM. A series of experiments have been conducted on an open-source emulator with encouraging results.

An Accelerating Approach for Blockchain Information Transmission Based on NDN

Blockchain is becoming more and more popular in various fields. Since the information transmission mode of the blockchain is data broadcasting, the traditional TCP/IP network cannot support the blockchain system well, but the Named-Data Networking (NDN) could be a good choice because of its multi-path forwarding and intra-network caching functions. In this article, we propose a new blockchain information transmission acceleration strategy (AITS) combining with graph theory and probability theory based on the NDN architecture. We select some more important nodes in the network as “secondary nodes”, and give them more bandwidth and cache space to assist the NDN network in data transmission. In order to select the correct node as the secondary node, we present a method to calculate the number of secondary nodes, and give the function to calculate the importance of each node. The simulation results show that in complex networks, the proposed method has superior performance in accelerating information transmission and reducing data overhead.

HDFTL: An On-Demand Flash Translation Layer Algorithm for Hybrid Solid State Drives

NAND flash-based solid-state drives (SSDs) have been widely used in consumer electronic products such as smartphones, digital video recorders, and laptops. The flash translation layer (FTL) is crucial to the performance of SSDs. In this article, an on-demand FTL, briefly as HDFTL, is proposed for hybrid SSDs built with SLC+MLC flash memory. HDFTL divides the SLC into data blocks and translation blocks and uses all MLC as data blocks. All mapping items are stored in the translation block of the SLC, and partial mapping items are loaded into the cached mapping table of the FTL as needed. The contributions of HDFTL are as follows: (1) Unify the address mapping method of SLC and MLC areas to simplify the FTL design of hybrid SSDs; (2) Split the cached mapping table into a hot-write mapping table and a normal mapping table and use time locality to solve hot-write identification problem in hybrid SSDs; (3) According to the relative wear rate of SLC and MLC areas, adaptively adjust the size of the hot-write mapping table and the normal mapping table. Experimental results show that the performance of HDFTL is better than that of the existing FTLs for hybrid SSDs.

Estimation of Node Cache Occupancy in Satellite Storage Network

The satellite network with cache function becomes the future development trend. How to efficiently use the node cache of the satellite network has become a research hotspot. A theoretical problem that needs to be solved in the latest research on effective utilization of cache is the estimation of cache occupancy. Based on the martingale encapsulation theory, combined with the channel conditions, access protocols, and queuing strategies in the satellite storage network, a satellite node occupancy estimation method and theoretical bounds are proposed in a two-layer satellite network of GEO and LEO. The accuracy of the martingale encapsulation method in estimating the cache occupancy is estimated by simulations. The simulation results show that our method is precise. The cache occupancy estimation method we proposed provides a theoretical basis for the optimal allocation of satellite cache resources.

The Sampling and Caching Subsystem (SCS) for the Scientific Exploration of Jezero Crater by the Mars 2020 Perseverance Rover

The Mars 2020 mission seeks to conduct a new scientific exploration on the surface of Mars. The Perseverance Rover will be sent to the surface of the Jezero Crater region to study its habitability, search for biosignatures of past life, acquire and cache samples for potential return, and prepare for possible human missions. To enable these objectives, an innovative Sampling and Caching Subsystem (SCS) has been developed and tested to allow the Perseverance Rover to acquire and cache rock core and regolith samples, prepare abraded rock surfaces, and support proximity science instruments. The SCS consists of the Robotic Arm (RA), the Turret and Corer, and the Adaptive Caching Assembly (ACA). These elements reside and interact both inside and outside of the Perseverance Rover to enable surface interactions, sample transfer, and caching. The main body of the Turret consists of the Coring Drill (Corer) with a Launch Abrading Bit initially installed prior to launch. Mounted to the Turret main structure are two proximity science instruments, SHERLOC and PIXL, as well as the Gas Dust Removal Tool (gDRT) and the Facility Contact Sensor (FCS). These work together with the RA to provide the sample acquisition, abraded surface preparation, and proximity science functions. The ACA is a network of assemblies largely inside the front belly of the Rover, which combine to perform the sample handling and caching functions of the mission. The ACA primarily consists of the Bit Carousel, the Sample Handling Assembly (SHA), End Effector (EE), Sample Tubes and their Sample Tube Storage Assembly (STSA), Seals and their Dispenser, Volume, and Tube Assembly (DVT), the Sealing Station, the Vision Station, the Cover Parking Lot, and additional supporting hardware. These components attach to the Caching Component Mounting Deck (CCMD) that is integrated with the Rover interior. This work describes these major elements of the SCS, with an emphasis on the functionality required to perform the set of tasks and interactions required by the subsystem. Key considerations of contamination control and biological cleanliness throughout the development of these hardware elements are also discussed. Additionally, aspects of testing and validating the functionality of the SCS are described. Early prototypes and tests matured the designs over several years and eventually led to the flight hardware and integrated testing in both Earth ambient and Mars-like environments. Multiple unique testbed venues were developed and used to enable testing from low-level mechanism operation through end-to-end sampling and caching interactions with the full subsystem and flight software. Various accomplishments from these testing efforts are highlighted. These past and ongoing tests support the successful preparations of the SCS on its pathway to operations on Mars.

Probabilistic computation offloading and data caching assisted by mobile-edge-computing–enabled base stations

Mobile edge computing can augment the capabilities of mobile terminals (MTs) by enabling computing and caching functionalities for base stations (BSs). Because BSs have only limited computation and storage resources compared with cloud servers, they need to efficiently manage the computation offloading and data caching for MTs. In this paper, a novel scheme for efficient computation offloading and data caching assisted by mobile-edge-computing–enabled BSs (MEC-BSs) is proposed. To maximize the MT benefits in terms of reduced time and energy consumption, our scheme determines the probability that each MT offloads each type of its tasks to the MEC-BS and indicates whether the cloud data for each type of MT task is cached at the MEC-BS. A balance factor is used to flexibly adjust the tendency of the optimization between the minimization of time and energy consumption. Based on the stable probabilistic characteristics of MT tasks and the MEC-BS service, the optimization algorithm of our scheme can be executed independently and concurrently without deteriorating the system performance. The simulation results demonstrate that our scheme can largely improve the system performance and that it always outperforms other reference schemes in scenarios with multiple criteria.

FTRM: A Cache-Based Fault Tolerant Recovery Mechanism for Multi-Channel Flash Devices

Flash memory prevalence has reached greater extents with its performance and compactness capabilities. This enables it to be easily adopted as storage media in various portable devices which includes smart watches, cell-phones, drones, and in-vehicle infotainment systems to mention but a few. To support large flash storage in such portable devices, existing flash translation layers (FTLs) employ a cache mapping table (CMT), which contains a small portion of logical page number to physical page number (LPN-PPN) mappings. For robustness, it is of importance to consider the CMT reconstruction mechanisms during system recovery. Currently, existing approaches cannot overcome the performance penalty after experiencing unexpected power failure. This is due to the disregard of the delay caused by inconsistencies between the cached page-mapping entries in RAM and their corresponding mapping pages in flash storage. Furthermore, how to select proper pages for reconstructing the CMT when rebooting a device needs to be revisited. In this study we address these problems and propose a fault tolerant power-failure recovery mechanism (FTRM) for flash memory storage systems. Our empirical study shows that FTRM is an efficient recovery and robust protocol.

GFTL: Group-Level Mapping in Flash Translation Layer to Provide Efficient Address Translation for NAND Flash-Based SSDs

NAND flash memory has been widely used as data storage devices in consumer electronics, such as tablet computers and smart phones. Logical-to-physical address translation is important for improving the performance of NAND flash-based SSDs. Even though keeping the mapping table in a DRAM can boost the address translation, it is already infeasible to do this as the capacity of SSDs keeps increasing and only a limited part of DRAM will be used as the mapping cache. Orthogonal to the demand-based page-level FTLs, we develop a novel group-level mapping which divides the whole SSD into multiple equal-size groups. To map a logical-page-number to a physical-page-number, it will be translated into a group number and an offset. The group number can be obtained via calculation, and the offset will be retrieved from a recorded mapping entry which can correspond to any position within a group. Group-level mapping reduces the size of mapping table while obtaining the similar flexibility as the page-level mapping. We also design an effective group-level FTL (GFTL) with a block pool management approach. Our simulations show that GFTL improves the hit ratio of mapping cache and thus reduces the average response time.

ELC: Edge Linked Caching for content updating in information-centric Internet of Things

Internet of things (IoT) has enabled every thing around us to have an Internet connection. In the future, IoT will generate more content than any other network. It is estimated that about 27 billion Internet enabled devices will connect to the Internet. For IoT, the current IP-based architecture, also known as Host-centric architecture, is not suitable. Therefore, a clean slate architecture is required to provide solutions to the problem. The researchers have recently proposed an appropriate architecture for this purpose, known as Information-Centric Network (ICN). ICN would potentially become the future Internet architecture as it has the ability to manage this huge number of IoT devices and their content. ICN’s in-network caching functionality is very useful for IoT, as it reduces the overhead of the publisher with respect to content access. This paper proposes an IoT caching strategy based on ICN that will effectively cache IoT data as well as update and evict content based on its freshness values.

High‐efficient superblock flash translation layer for NAND flash controller

Flash controller is the core hardware embedded in today's mobile device storage, and the flash translation layer (FTL) is the key system of controller. This Letter proposes a high-efficient superblock FTL (HSPB) to satisfy the demand of large media files and application files storage, which implements the cross-block sequential writing strategy and the shared cached mapping table scheme. Test results show that HSPB reduces the time and power consumption by 7–30% in seq/random write and gains up to 60% improvement in sequential/random read compared to other FTLs.

CCN-Based Inter-Vehicle Communication for Efficient Collection of Road and Traffic Information

Recently, inter-vehicle communication, which helps to avoid collision accidents (by driving safety support system) and facilitate self-driving (by dissemination of road and traffic information), has attracted much attention. In this paper, in order to efficiently collect road/traffic information in the request/response manner, first a basic method, Content-centric network (CCN) for Vehicular network (CV), is proposed, which applies CCN cache function to inter-vehicle communication. Content naming and routing, which take vehicle mobility into account, are investigated. On this basis, the CV method is extended (called ECV) to avoid the cache miss problem caused by vehicle movement, and is further enhanced (called ECV+) to more efficiently exploit cache buffer in vehicles, caching content according to a probability decided by a channel usage rate. Extensive evaluations on the network simulator Scenargie, with a realistic open street map, confirm that the CV method and its extensions (ECV, ECV+) effectively reduce the average number of hops of data packets (by up to 47%, 63%, and 83%, respectively) and greatly improve the content acquisition success rate (by up to 356%, 444%, and 689%, respectively), compared to the method without a cache mechanism.

SDATP: An SDN-Based Traffic-Adaptive and Service-Oriented Transmission Protocol

In this paper, a software-defined networking (SDN) based adaptive transmission protocol (SDATP) is proposed to support applications in fifth generation (5G) communication networks. For time-critical services, such as machine-type communication services for industrial automation, high reliability and low latency are required. To guarantee the strict service requirements, a slice-level customized protocol is developed with in-network intelligence, including in-path caching-based retransmission and in-network congestion control. To further reduce the delay for end-to-end (E2E) service delivery, we jointly optimize the placement of caching functions and packet caching probability, which reduces E2E delay by minimizing retransmission hops. Since the joint optimization problem is NP-hard, we transform the original problem to a simplified form and propose a low-complexity heuristic algorithm to solve the simplified problem. Numerical results are presented to validate the proposed probabilistic caching algorithm, including its adaptiveness to network dynamics and its effectiveness in reducing retransmission hops. Simulation results demonstrate the advantages of the proposed SDATP over the conventional transport layer protocol with respect to E2E packet delay.

Evolution of application-specific cache mappings

Reconfigurable caches offer an intriguing opportunity to tailor cache behavior to applications for better run-times and energy consumptions. While one may adapt structural cache parameters such as cache and block sizes, we adapt the memory-address-to-cache-index mapping function to the needs of an application. Using a LEON3 embedded multi-core processor with reconfigurable cache mappings, a metaheuristic search procedure, and MiBench applications, we show in this work how to accurately compare non-deterministic performances of applications and how to use this information to implement an optimization procedure that evolves application-specific cache mappings for the LEON3 multi-core processor.

Linear Network Coded Wireless Caching in Cloud Radio Access Network

This paper investigates a cache-aided cloud radio access network (C-RAN), comprising a central unit, K base stations (BSs) each with N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> antennas, and M users each with N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</sub> antennas, where each BS and user have local caches to store some popular contents from the central unit. For this cache-aided network, we propose the linear network coded (NC) wireless caching that consists of linear wireless network coding assisted cache placement phase and signal-space alignment (SSA) enabled content delivery phase. In the cache placement phase, we design a joint NC caching function at the BSs to store linear combinations of messages from the central unit, as a form of linear wireless network coding. In the content delivery phase, we design the SSA pattern based on the NC caching to guide the precoding designs at BSs. Then, each user can reliably decode its requested messages by receiver shaping and reverse NC operation. The primary contribution of this work is to achieve the coding gain induced by the integration of linear wireless network coding and SSA, which has been not exploited in the field of wireless coded caching. In particular, to deal with high temporal variability of user requests, we show that the proposed cache placement is invariant to different user requests in the worst-case caching, without any shared caching messages at different BSs. Furthermore, we verify that the proposed scheme is also compatible with the insufficient caching scenario at the BSs. In addition, we analyze the achievable sum degrees of freedom (DoF) for the proposed caching network. Both analytical and numerical results verify that the proposed caching scheme achieves a higher sum DoF than the existing related works.

Nordugrid ARC Datastaging and Cache: Efficiency gains on HPC and cloud resources

The Worldwide LHC Computing Grid (WLCG) is today comprised of a range of different types of resources such as cloud centers, large and small HPC centers, volunteer computing as well as the traditional grid resources. The Nordic Tier 1 (NT1) is a WLCG computing infrastructure distributed over the Nordic countries. The NT1 deploys the Nordugrid ARC-CE, which is non-intrusive and lightweight, originally developed to cater for HPC centers where no middleware could be installed on the worker nodes. The NT1 runs ARC in the native Nordugrid mode which contrary to the Pilot mode leaves jobs data transfers up to ARC. ARCs data transfer capabilities together with the ARC Cache are the most important features of ARC. In this article we will describe the datastaging and cache functionality of the ARC-CE set up as an edge service to an HPC or cloud resource, and show the gain in efficiency this model provides compared to a traditional pilot model, especially for sites with remote storage.

SDATP: An SDN-Based Adaptive Transmission Protocol for Time-Critical Services

In this article, a comprehensive approach is proposed for 5G communication networks. In SDATP, a slice-level customized protocol is developed for supporting time-critical services that require high reliability and low-latency, such as MTC services for industrial automation. To satisfy service quality requirements for an MTC service, we introduce in-network intelligence in the proposed protocol, by enabling the functionalities of in-path caching, in-path retransmission, in-network congestion detection and congestion control. To minimize the E2E delay, we optimize the configuration of caching functionalities, including the number of enabled caching nodes, caching node placement, and probabilistic packet caching policy. Since the optimization problem is NP-hard, we simplify the problem by reducing the number of decision variables and propose a low-complexity algorithm to solve the simplified problem. Extensive simulation results are presented to validate the effectiveness of the proposed algorithm in terms of retransmission hops and its adaptiveness to network dynamics.

Transmission Protocol Customization for Network Slicing: A Case Study of Video Streaming

In this article, we propose a software-defined networking (SDN)-based transmission protocol (SDTP) for futuregeneration networks. Different services are supported by dedicated network slices, each of which can be operated separately with a customized transmission protocol. In particular, we focus on video streaming services supported by in-network caching functions. By exploiting the flexibility of scalable video coding (SVC) and SDN control intelligence, we present an in-network bottleneck queue management strategy in conjunction with a novel selective caching policy (SCP) for congestion detection and mitigation. Additionally, an enhanced transmission (ET) scheme is devised to improve the video user experience by opportunistically requesting cached video packets when network conditions permit. The proposed protocol can adapt to traffic dynamics and varying service requirements, and it is shown to effectively alleviate network congestion and provide a balanced user experience. Extensive simulation results are presented to validate the proposed protocol in terms of in-network queue stability and userperceived video quality.

Fog-Computing-Enabled Cognitive Network Function Virtualization for an Information-Centric Future Internet

Information-centric networking (ICN) is an important trend that will impact the future of the Internet. ICN caters to large content consumption patterns while achieving high performance. New features in the information-centric future Internet, such as caching, name-based routing, and content-based security, bring novel challenges to a decentralized environment. On one hand, the processing capabilities on the edge in an information-centric future Internet need to implement smart analysis for large quantities of content. On the other hand, the computational and storage resources need to be configured and controlled on demand and based on cognition of the content from users. To address these challenges, this article proposes a fog-computing- enabled cognitive network functions virtualization approach for an information-centric future Internet. We first propose an on-demand caching function virtualization scheme and design a communication scheme between the fog nodes and the future Internet nodes for the forwarding process. Then, to attain smart control for related operations (i.e., routing, cache policy, and security), we propose a control function virtualization approach. Finally, a cognitive resource configuration mechanism is proposed. The simulation results show the advantages and efficiency of the proposed approach.