| 1. |
- Sharma, Gourav Prateek, et al.
(författare)
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Toward Deterministic Communications in 6G Networks : State of the Art, Open Challenges and the Way Forward
- 2023
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Ingår i: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 11, s. 106898-106923
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Forskningsöversikt (refereegranskat)abstract
- Over the last decade, society and industries have undergone rapid digitization that is expected to lead to the evolution of the cyber-physical continuum. End-to-end deterministic communications infrastructure is the essential glue that will bridge the digital and physical worlds of the continuum. We describe the state of the art and open challenges with respect to contemporary deterministic communications and compute technologies- 3GPP 5G, IEEE Time-Sensitive Networking, IETF DetNet, OPC UA as well as edge computing. While these technologies represent significant technological advancements towards networking Cyber-Physical Systems (CPS), we argue in this paper that they rather represent a first generation of systems that are still limited in different dimensions. In contrast, realizing future deterministic communications systems requires, firstly, seamless convergence between these technologies and, secondly, scalability to support heterogeneous (time-varying requirements) arising from diverse CPS applications. In addition, future deterministic communication networks will have to provide such characteristics end-to-end, which for CPS refers to the entire communication and computation loop, from sensors to actuators. In this paper, we discuss the state of the art regarding the main challenges towards these goals: predictability, end-to-end technology integration, end-to-end security, and scalable vertical application interfacing. We then present our vision regarding viable approaches and technological enablers to overcome these four central challenges. In particular, we argue that there is currently a window of opportunity to establish, through 6G standardization, the foundations for a scalable and converged deterministic communications and compute infrastructure. Key approaches to leverage in that regard are 6G system evolutions, wireless-friendly 6G integration with TSN and DetNet, novel end-to-end security approaches, efficient edge-cloud integrations, data-driven approaches for stochastic characterization and prediction, as well as leveraging digital twins towards system awareness.
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| 2. |
- Araujo, Igor M., et al.
(författare)
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Availability-Guaranteed Service Function Chain Provisioning with Optional Shared Backups
- 2020
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Ingår i: 2020 16TH INTERNATIONAL CONFERENCE ON THE DESIGN OF RELIABLE COMMUNICATION NETWORKS DRCN 2020. - : IEEE.
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Konferensbidrag (refereegranskat)abstract
- The dynamic provisioning of Service Function Chain (SFC) using Virtual Network Functions (VNFs) is a challenging problem, especially for availability-constrained services. The provisioning of backup resources is often used to ensure that availability requirements are fulfilled. However, the assignment of backup resources should be carefully designed to avoid resource inefficiencies as much as possible. This paper proposes the Optional Backup with Shared Path and Shared Function (OBSPSF) strategy, which aims at improving resource efficiency while fulfilling the availability requirements of SFC requests. The strategy uses optional backup provisioning to ensure that backup resources are assigned only when strictly needed (i.e., when the SFC alone does not meet the availability constraint). Moreover, OBSPSF encourages backup sharing (among both connectivity and backup VNFs) to reduce the backup resource overhead. Results show that the strategy can accommodate orders-of-magnitude more services than benchmark heuristics from the literature.
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| 3. |
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| 4. |
- De Andrade, Marilet, et al.
(författare)
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Enhanced IPACT : solving the over-granting problem in long-reach EPON
- 2013
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Ingår i: Telecommunications Systems. - : Springer Science and Business Media LLC. - 1018-4864 .- 1572-9451. ; 54:2, s. 137-146
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we address an issue referred to as "over-granting problem", which is inherent in the existing dynamic bandwidth allocation algorithms for Ethernet-based Passive Optical Networks (EPON), in particular when deployed for multi-threaded scheme in long-reach scenario. In order to solve this problem we design a scheme for the algorithm of Interleaved Polling with Adapted Cycle Time (IPACT) with the limited service discipline. We evaluate the proposed scheme through simulations for single-thread and double-thread cases and demonstrate that, the network performance can be significantly improved by our solution in terms of average delay, jitter, and throughput.
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| 5. |
- De Andrade, Marilet, et al.
(författare)
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Evaluating Strategies for Evolution of Passive Optical Networks
- 2011
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Ingår i: IEEE Communications Magazine. - : IEEE. - 0163-6804 .- 1558-1896. ; 49:7, s. 176-184
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Tidskriftsartikel (refereegranskat)abstract
- Rapidly-increasing traffic demands will require the upgrade of optical access networks, namely deployed Passive Optical Networks (PONs), which may soon face capacity exhaustion. Such upgrade options must consider several technical and cost factors for evolution toward a shared multiple-channel PON using Wavelength-Division Multiplexing (WDM). WDM can facilitate the seamless upgrade of PONs, since capacity can be increased by adding new wavelength channels. We study the requirements for optimal migration toward higher bandwidth per user, and examine scenarios and cost-effective solutions for PON evolution.
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| 6. |
- Lin, Rui, et al.
(författare)
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Disaggregated Data Centers : Challenges and Tradeoffs
- 2019
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Resource utilization of modern data centers is significantly limited by the mismatch between the diversity of the resources required by running applications and the fixed amount of hardwired resources (e.g., number of central processing unit CPU cores, size of memory) in the server blades. In this regard, the concept of function disaggregation is introduced, where the integrated server blades containing all types of resources are replaced by the resource blades including only one specific function. Therefore, disaggregated data centers can offer high flexibility for resource allocation and hence their resource utilization can be largely improved. In addition, introducing function disaggregation simplifies the system upgrade, allowing for a quick adoption of new generation components in data centers. However, the communication between different resources faces severe problems in terms of latency and transmission bandwidth required. In particular,the CPU-memory interconnects in fully disaggregated data centers require ultra-low latency and ultra-high transmission bandwidth in order to prevent performance degradation for running applications. Optical fiber communication is a promising technique to offer high capacity and low latency, but it is still very challenging for the state-of-the-art optical transmission technologies to meet the requirements of the fully disaggregated data centers. In this paper, different levels of function disaggregation are investigated. For the fully disaggregated data centers, two architectural options are presented, where optical interconnects are necessary for CPU-memory communications. We review the state-of-the-art optical transmission technologies and carry out performance assessment when employing them to support function disaggregation in data centers. The results reveal that function disaggregation does improve the efficiency of resource usage in the data centers, although the bandwidth provided by the state-of-the-art optical transmission technologies is not always sufficient for the fully disaggregated data centers. It calls for research in optical transmission to fully utilize the advantages of function disaggregation in data centers.
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| 7. |
- Lin, Rui, 1988, et al.
(författare)
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Disaggregated Data Centers: Challenges and Trade-offs
- 2020
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Ingår i: IEEE Communications Magazine. - : Institute of Electrical and Electronics Engineers (IEEE). - 0163-6804 .- 1558-1896. ; 58:2, s. 20-26
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Tidskriftsartikel (refereegranskat)abstract
- Disaggregated data centers (DCs) can offer high flexibility for resource allocation; hence, their resource utilization can be significantly improved. However, communications between different types of resources, in particular between CPU and memory, in fully disaggregated DCs face severe problems in terms of stringent requirements for ultra-low latency and ultra-high transmission bandwidth. Optical fiber communication is promising to provide high capacity and low latency, but it is still challenging for the state-of-the-art optical technologies to meet the requirements of fully disaggregated DCs. In this article, different levels of resource disaggregation are investigated. For fully disaggregated DCs, two architectural options are presented, where optical interconnects are necessary for the CPU-memory communications. We review the state-of-the-art optical transmission and switching technologies, and analyze pros and cons of their applicability in the disaggregated DCs. The results reveal that resource disaggregation does improve the resource utilization in DCs. However, the bandwidth provided by the state-of-the-art technologies is not always sufficient for fully disaggregated DCs. It calls for further advances in optical communications to fully utilize the advantages of fully disaggregated DCs.
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| 8. |
- Varasteh, Amir, et al.
(författare)
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Power-Aware Virtual Network Function Placement and Routing using an Abstraction Technique
- 2018
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Ingår i: 2018 IEEE Global Communications Conference, GLOBECOM 2018 - Proceedings. - : IEEE. - 9781538647271
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Konferensbidrag (refereegranskat)abstract
- The Network Function Virtualization (NFV) is very promising for efficient provisioning of network services and is attracting a lot of attention. NFV can be implemented in commercial off-the-shelf servers or Physical Machines (PMs), and many network services can be offered as a sequence of Virtual Network Functions (VNFs), known as VNF chains. Furthermore, many existing network devices (e.g., switches) and collocated PMs are underutilized or over-provisioned, resulting in low power-efficiency. In order to achieve more energy efficient systems, this work aims at designing the placement of VNFs such that the total power consumption in network nodes and PMs is minimized, while meeting the delay and capacity requirements of the foreseen demands. Based on existing switch and PM power models, we formulate an Integer Linear Programming (ILP) model to find the optimal solution. We also propose a heuristic based on the concept of Blocking Islands (BI), and a baseline heuristic based on the Betweenness Centrality (BC) property of the graph. Both heuristics and the ILP solutions have been compared in terms of total power consumption, delay, demands acceptance rate, and computation time. Our simulation results suggest that BI-based heuristic is superior compared with the BC-based heuristic, and very close to the optimal solution obtained from the ILP in terms of total power consumption and demands acceptance rate. Compared to the ILP, the proposed BI-based heuristic is significantly faster and results in 22% lower end-to-end delay, with a penalty of consuming 6% more power in average.
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