2023
Feltin, Thomas; Marché, Léo; Cordero, Juan Antonio; Brockners, Frank; Clausen, Thomas
DNN Partitioning for Inference Throughput Acceleration at the Edge Journal Article
In: IEEE Access, 2023, ISSN: 2169-3536.
@article{nokey,
title = {DNN Partitioning for Inference Throughput Acceleration at the Edge},
author = {Thomas Feltin and Léo Marché and Juan Antonio Cordero and Frank Brockners and Thomas Clausen},
editor = {IEEE},
url = {https://ieeexplore.ieee.org/document/10042405},
doi = {10.1109/ACCESS.2023.3244497},
issn = {2169-3536},
year = {2023},
date = {2023-02-13},
journal = {IEEE Access},
abstract = {Deep neural network (DNN) inference on streaming data requires computing resources to satisfy inference throughput requirements. However, latency and privacy sensitive deep learning applications cannot afford to offload computation to remote clouds because of the implied transmission cost and lack of trust in third-party cloud providers. Among solutions to increase performance while keeping computation on a constrained environment, hardware acceleration can be onerous, and model optimization requires extensive design efforts while hindering accuracy. DNN partitioning is a third complementary approach, and consists of distributing the inference workload over several available edge devices, taking into account the edge network properties and the DNN structure, with the objective of maximizing the inference throughput (number of inferences per second). This paper introduces a method to predict inference and transmission latencies for multi-threaded distributed DNN deployments, and defines an optimization process to maximize the inference throughput. A branch and bound solver is then presented and analyzed to quantify the achieved performance and complexity. This analysis has led to the definition of the acceleration region, which describes deterministic conditions on the DNN and network properties under which DNN partitioning is beneficial. Finally, experimental results confirm the simulations and show inference throughput improvements in sample edge deployments.},
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2022
Yao, Zhiyuan; Desmouceaux, Yoann; Cordero, Juan Antonio; Townsley, Mark; Clausen, Thomas Heide
Aquarius-Enable Fast, Scalable, Data-Driven Service Management in the Cloud Journal Article
In: IEEE Transactions on Network and Service Management, 2022, ISSN: 1932-4537.
@article{nokeyi,
title = {Aquarius-Enable Fast, Scalable, Data-Driven Service Management in the Cloud},
author = {Zhiyuan Yao and Yoann Desmouceaux and Juan Antonio Cordero and Mark Townsley and Thomas Heide Clausen},
url = {https://ieeexplore.ieee.org/abstract/document/9852806},
doi = {10.1109/TNSM.2022.3197130},
issn = {1932-4537},
year = {2022},
date = {2022-12-01},
urldate = {2022-12-01},
journal = {IEEE Transactions on Network and Service Management},
abstract = {In order to dynamically manage and update networking policies in cloud data centers, Virtual Network Functions (VNFs) use, and therefore actively collect, networking state information -and in the process, incur additional control signaling and management overhead, especially in larger data centers. In the meantime, VNFs in production prefer distributed and straightforward heuristics over advanced learning algorithms to avoid intractable additional processing latency under high-performance and low-latency networking constraints. This paper identifies the challenges of deploying learning algorithms in the context of cloud data centers, and proposes Aquarius to bridge the application of machine learning (ML) techniques on distributed systems and service management. Aquarius passively yet efficiently gathers reliable observations, and enables the use of ML techniques to collect, infer, and supply accurate networking state information -without incurring additional signaling and management overhead. It offers fine-grained and programmable visibility to distributed VNFs, and enables both open-and close-loop control over networking systems. This paper illustrates the use of Aquarius with a traffic classifier, an auto-scaling system, and a load balancer -and demonstrates the use of three different ML paradigms -unsupervised, supervised, and reinforcement learning, within Aquarius, for network state inference and service management. Testbed evaluations show that Aquarius suitably improves network state visibility and brings notable performance gains for various scenarios with low overhead.},
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Yao, Zhiyuan; Desmouceaux, Yoann; Cordero, Juan Antonio; Clausen, Thomas Heide
HLB: Towards Load-Aware Load-Balancing Journal Article
In: IEEE/ACM Transactions on Networking, 2022, ISSN: 1558-2566.
@article{nokey,
title = {HLB: Towards Load-Aware Load-Balancing},
author = {Zhiyuan Yao and Yoann Desmouceaux and Juan Antonio Cordero and Thomas Heide Clausen},
doi = {10.1109/TNET.2022.3177163},
issn = {1558-2566},
year = {2022},
date = {2022-06-05},
urldate = {2022-06-05},
journal = {IEEE/ACM Transactions on Networking},
abstract = {The purpose of network load balancers is to optimize quality of service to the users of a set of servers - basically, to improve response times and to reducing computing resources - by properly distributing workloads. This paper proposes a distributed, application-agnostic, Hybrid Load Balancer (HLB) that - without explicit monitoring or signaling - infers server occupancies and processing speeds, which allows making optimised workload placement decisions. This approach is evaluated both through simulations and extensive experiments, including synthetic workloads and Wikipedia replays on a real-world testbed. Results show significant performance gains, in terms of both response time and system utilisation, when compared to existing load-balancing algorithms.},
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2020
Desmouceaux, Yoann; Enguehard, Marcel; Clausen, Thomas
Joint Monitorless Load-Balancing and Autoscaling for Zero-Wait-Time in Data Centers Journal Article
In: IEEE Transactions on Network and Service Management, 2020.
@article{Desmouceaux2020,
title = {Joint Monitorless Load-Balancing and Autoscaling for Zero-Wait-Time in Data Centers},
author = {Yoann Desmouceaux and Marcel Enguehard and Thomas Clausen},
url = {https://www.epizeuxis.net/wp-content/uploads/2020/12/Joint-Monitorless-Load-Balancing-and-Autoscaling-for-Zero-Wait-Time-in-Data-Centers.pdf},
doi = {10.1109/TNSM.2020.3045059},
year = {2020},
date = {2020-12-31},
urldate = {2020-12-31},
journal = {IEEE Transactions on Network and Service Management},
abstract = {Cloud architectures achieve scaling through two main functions: (i) load-balancers, which dispatch queries among replicated virtualized application instances, and (ii) autoscalers, which automatically adjust the number of replicated instances to accommodate variations in load patterns. These functions are often provided through centralized load monitoring, incurring operational complexity. This paper introduces a unified and centralized-monitoring-free architecture achieving both autoscal- ing and load-balancing, reducing operational overhead while increasing response time performance. Application instances are virtually ordered in a chain, and new queries are forwarded along this chain until an instance, based on its local load, accepts the query. Autoscaling is triggered by the last application instance, which inspects its average load and infers if its chain is under- or over-provisioned. An analytical model of the system is derived, and proves that the proposed technique can achieve asymptotic zero-wait time with high (and controlable) probability. This result is confirmed by extensive simulations, which highlight close-to- ideal performance in terms of both response time and resource costs.},
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Hawari, Mohammed; Cordero, Juan Antonio; Clausen, Thomas
High-Accuracy Packet Pacing on Commodity Servers for Constant-Rate Flows Journal Article
In: IEEE/ACM Transactions on Networking, pp. 1-15, 2020, ISSN: 1558-2566.
@article{9130915,
title = {High-Accuracy Packet Pacing on Commodity Servers for Constant-Rate Flows},
author = {Mohammed Hawari and Juan Antonio Cordero and Thomas Clausen},
url = {https://www.thomasclausen.net/wp-content/uploads/2020/08/2020-IEEE-TNET-High-Accuracy-Packet-Pacing-on-Commodity-Servers-for-Constant-Rate-Flows.pdf},
doi = {10.1109/TNET.2020.3001672},
issn = {1558-2566},
year = {2020},
date = {2020-01-01},
urldate = {2020-01-01},
journal = {IEEE/ACM Transactions on Networking},
pages = {1-15},
abstract = {This addresses the problem of high-quality packet pacing for constant-rate packet consumption systems, with strict buffering limitations. A mostly-software pacing architecture is developed, which has minimal hardware requirements, satisfied by commodity servers - rendering the proposed solution easily deployable in existing (data-centre) infrastructures. Two algorithms (free-running and frequency-controlled pacing, for explicitly and implicitly indicated target rates, respectively) are specified, and formally analysed. The proposed solution, including both algorithms, is implemented, and is tested on real hardware and under real conditions. The performance of these implementations is experimentally evaluated and compared to existing mechanisms, available in general-purpose hardware. Results of both exhaustive experiments, and of an analytical modeling, indicate that the proposed approach is able to perform low-jitter packet pacing on commodity hardware, being thus suitable for constant rate transmission and consumption in media production scenarios.},
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2019
Desmouceaux, Yoann; Cordero, Juan Antonio; Clausen, Thomas
Reliable B.I.E.R. with Peer Caching Journal Article
In: IEEE Transactions on Network and Service Management, 2019, ISSN: 1932-4537.
@article{Desmouceaux2019,
title = {Reliable B.I.E.R. with Peer Caching},
author = {Yoann Desmouceaux and Juan Antonio Cordero and Thomas Clausen},
url = {https://www.thomasclausen.net/wp-content/uploads/2019/11/Reliable-B.I.E.R.-with-Peer-Caching.pdf},
doi = {10.1109/TNSM.2019.2950158},
issn = {1932-4537},
year = {2019},
date = {2019-11-01},
journal = {IEEE Transactions on Network and Service Management},
abstract = {Multicast protocols usually require building multicast trees and maintaining state in intermediate routers, incurring operation complexity. B.I.E.R. (Bit-Indexed Explicit Replication) ambitions to alleviate this complexity by allowing for source-driven selection of destinations and state-less packet forwarding. B.I.E.R. can also be used to achieve reliable delivery of content, by retransmitting packet to the exact set of destinations which have missed it. While B.I.E.R.- based reliable multicast exhibits attractive performance attributes, repair of a lost packet is achieved through source retransmissions, which may be costly and even unnecessary if close peers are able to provide a copy of the packet.
Thus, this paper extends the use of reliable B.I.E.R. multicast to allow recoveries from peers, using Segment Routing (SR) to steer retransmission requests through potential candidates. A framework is introduced, which can accommodate different policies for the selection of candidate peers for retransmissions. Simple (both static and adaptive) policies are introduced and analyzed, both (i) theoretically and (ii) by way of simulations in data-center-like and real-world topologies. Results indicate that local peer recovery is able to substantially reduce the overall retransmission traffic, and that this can be achieved through simple policies, where no signaling is required to build a set of candidate peers.},
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Thus, this paper extends the use of reliable B.I.E.R. multicast to allow recoveries from peers, using Segment Routing (SR) to steer retransmission requests through potential candidates. A framework is introduced, which can accommodate different policies for the selection of candidate peers for retransmissions. Simple (both static and adaptive) policies are introduced and analyzed, both (i) theoretically and (ii) by way of simulations in data-center-like and real-world topologies. Results indicate that local peer recovery is able to substantially reduce the overall retransmission traffic, and that this can be achieved through simple policies, where no signaling is required to build a set of candidate peers.
2018
Cordero, Juan Antonio; Lou, Wei
Take your time, get it closer: content dissemination within mobile pedestrian crowds Journal Article
In: Wireless Networks, 2018, ISSN: 1572-8196.
@article{Cordero2018,
title = {Take your time, get it closer: content dissemination within mobile pedestrian crowds},
author = {Juan Antonio Cordero and Wei Lou},
url = {https://doi.org/10.1007/s11276-018-1731-2},
doi = {10.1007/s11276-018-1731-2},
issn = {1572-8196},
year = {2018},
date = {2018-05-05},
journal = {Wireless Networks},
abstract = {The explosion of traffic demands in the edge of the Internet, mostly by mobile users, is putting under pressure current networking infrastructures. This is particularly acute when huge amounts of users and active wireless devices gather in reduced geographical spaces, increasing the risk of exceeding planned capacity of deployed infrastructure. This trend motivates research on edge computing, and in particular, on mechanisms to offload or address locally part of the user injected traffic at the access infrastructure, thus reducing the need of Internet requests and retrievals. This paper concentrates on the ability of mobile crowds --and corresponding access networks---to fulfill content requests originated within the mesh, with minimal intervention of the Internet infrastructure. Simple heuristics are revisited, proposed, discussed and evaluated to improve autonomous content discovery and dissemination within high-density, low-mobility crowds, by combining notions already explored for MANET routing: deliberate jittering and autonomous distance-based overlay pruning. Results over synthetic networks and real mobility traces indicate that these mechanisms improve efficiency and quality of content request discoveries, by reducing significantly collisions and increasing stability of discovered paths in dense pedestrian crowds.},
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Clausen, Thomas; YI, Jiazi; Cordero, Juan Antonio; Igarashi, Yuichi
Use 'em or Lose 'em: On Unidirectional Links in Reactive Routing Protocols Journal Article
In: Elsevier Ad Hoc Networks, vol. 73, pp. 51-64, 2018.
@article{Clausen2018unidirectional,
title = {Use 'em or Lose 'em: On Unidirectional Links in Reactive Routing Protocols},
author = {Thomas Clausen and Jiazi YI and Juan Antonio Cordero and Yuichi Igarashi},
url = {https://ac.els-cdn.com/S1570870518300325/1-s2.0-S1570870518300325-main.pdf?_tid=0b7f4a7e-b489-4317-b96c-f18cec2af56f&acdnat=1520779362_84dbf04f92cfc3c7ef2448f3b4c3ebf7},
doi = {10.1016/j.adhoc.2018.02.004},
year = {2018},
date = {2018-05-01},
journal = {Elsevier Ad Hoc Networks},
volume = {73},
pages = {51-64},
abstract = {In reactive unicast routing protocols, Route Discovery aims to include only bidirectional links in discovered routing paths. This is typically accomplished by having routers maintain a “blacklist” of links recently confirmed (through Route Reply processing) to be unidirectional – which is then used for excluding subsequent Route Discovery control messages received over these links from being processed and forwarded.
This paper first presents an analytical model, which allows to study the impact of unidirectional links being present in a network, on the performance of reactive routing protocols. Next, this paper identifies that despite the use of a “blacklist”, the Route Discovery process may result in discovery of false forward routes, i.e., routes containing unidirec- tional links – and proposes a counter-measure denoted Forward Bidirectionality Check. This paper further proposes a Loop Exploration mechanism, allowing to properly include unidirectional links in a discovered routing topology – with the goal of providing bidirectional connectivity even in absence of bidirectional paths in the network.
Finally, each of these proposed mechanisms are subjected to extensive network simulations in static scenarios. When the fraction of unidirectional links is moderate (15 50%), simulations find Forward Bidirectionality Check to significantly increase the probability that bidirectional routing paths can be discovered by a reactive routing protocol, while incurring only an insignificant additional overhead. Further, in networks with a significant fraction of unidirectional links ( 50%), simulations reveal that Loop Exploration preserves the ability of a reactive routing protocol to establish bidirectional communication (possibly through non-bidirectional paths), but at the expense of a substantial additional overhead.},
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This paper first presents an analytical model, which allows to study the impact of unidirectional links being present in a network, on the performance of reactive routing protocols. Next, this paper identifies that despite the use of a “blacklist”, the Route Discovery process may result in discovery of false forward routes, i.e., routes containing unidirec- tional links – and proposes a counter-measure denoted Forward Bidirectionality Check. This paper further proposes a Loop Exploration mechanism, allowing to properly include unidirectional links in a discovered routing topology – with the goal of providing bidirectional connectivity even in absence of bidirectional paths in the network.
Finally, each of these proposed mechanisms are subjected to extensive network simulations in static scenarios. When the fraction of unidirectional links is moderate (15 50%), simulations find Forward Bidirectionality Check to significantly increase the probability that bidirectional routing paths can be discovered by a reactive routing protocol, while incurring only an insignificant additional overhead. Further, in networks with a significant fraction of unidirectional links ( 50%), simulations reveal that Loop Exploration preserves the ability of a reactive routing protocol to establish bidirectional communication (possibly through non-bidirectional paths), but at the expense of a substantial additional overhead.
Desmouceaux, Yoann; Toubaline, Sonia; Clausen, Thomas
Flow-Aware Workload Migration in Data Centers Journal Article
In: Springer - Journal of Network and Systems Management (JONS), 2018.
@article{Desmouceaux2018a,
title = {Flow-Aware Workload Migration in Data Centers},
author = {Yoann Desmouceaux and Sonia Toubaline and Thomas Clausen},
url = {https://link.springer.com/epdf/10.1007/s10922-018-9452-5?author_access_token=qm_40d91CsNLlZ_vZ0tZFPe4RwlQNchNByi7wbcMAY4xSrvbLplDMLQ3AN9vWEoUIxtZAIdnOGAzJH5W3YOrbGteOLvaEXsEE1xFv66lVxTKlL40BAS25fsaLf8w1RJAvY69owHWqhJkTmAZpvdCkQ%3D%3D
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doi = {10.1007/s10922-018-9452-5},
year = {2018},
date = {2018-03-10},
journal = {Springer - Journal of Network and Systems Management (JONS)},
abstract = {In data centers, subject to workloads with heterogeneous (and sometimes short) lifetimes, workload migration is a way of attaining a more efficient utilization of the underlying physical machines.
To not introduce performance degradation, such workload migration must take into account not only machine resources, and per-task resource requirements, but also application dependencies in terms of network communication.
This articleformat presents a workload migration model capturing all of these constraints.
A linear programming framework is developed allowing accurate representation of per-task resources requirements and inter-task network demands. Using this, a multi-objective problem is formulated to compute a re-allocation of tasks that (i) maximizes the total inter-task throughput, while (ii) minimizing the cost incurred by migration and (iii) allocating the maximum number of new tasks.
A baseline algorithm, solving this multi-objective problem using the $epsilon$-constraint method is proposed, in order to generate the set of Pareto-optimal solutions. As this algorithm is compute-intensive for large topologies, a heuristic, which computes an approximation of the Pareto front, is then developed, and evaluated on different topologies and with different machine load factors. These evaluations show that the heuristic can provide close-to-optimal solutions, while reducing the solving time by one to two order of magnitudes.
},
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To not introduce performance degradation, such workload migration must take into account not only machine resources, and per-task resource requirements, but also application dependencies in terms of network communication.
This articleformat presents a workload migration model capturing all of these constraints.
A linear programming framework is developed allowing accurate representation of per-task resources requirements and inter-task network demands. Using this, a multi-objective problem is formulated to compute a re-allocation of tasks that (i) maximizes the total inter-task throughput, while (ii) minimizing the cost incurred by migration and (iii) allocating the maximum number of new tasks.
A baseline algorithm, solving this multi-objective problem using the $epsilon$-constraint method is proposed, in order to generate the set of Pareto-optimal solutions. As this algorithm is compute-intensive for large topologies, a heuristic, which computes an approximation of the Pareto front, is then developed, and evaluated on different topologies and with different machine load factors. These evaluations show that the heuristic can provide close-to-optimal solutions, while reducing the solving time by one to two order of magnitudes.
Desmouceaux, Yoann; Clausen, Thomas; Cordero, Juan Antonio; Townsley, W. Mark
Reliable Multicast with B.I.E.R. Journal Article
In: IEEE/KICS Journal of Communications and Networks (JCN), vol. 20, no. 2, pp. 182-197, 2018.
@article{Desmouceaux0000,
title = {Reliable Multicast with B.I.E.R.},
author = {Yoann Desmouceaux and Thomas Clausen and Juan Antonio Cordero and W. Mark Townsley },
url = {http://www.thomasclausen.net/wp-content/uploads/2018/03/jcn-2018.pdf},
year = {2018},
date = {2018-02-28},
journal = {IEEE/KICS Journal of Communications and Networks (JCN)},
volume = {20},
number = {2},
pages = {182-197},
abstract = {Inter-network multicast protocols, which build and maintain multicast trees, incur both explicit protocol signalling, and maintenance of state in intermediate routers in the network. B.I.E.R. (Bit-Indexed Explicit Replication) is a technique which can provide a multicast service yet removes such complexities: in- termediate routers are unencumbered by group management, and no per-group state is to be maintained.
This paper explores the use of B.I.E.R. as a basis for develop- ing an efficient and reliable multicast mechanism, where redun- dant traffic is avoided, essential traffic is forwarded along shortest paths, and no per-flow state is required in intermediate routers. Evaluated by way of both an analytical model and network sim- ulation both in generic and in real network topologies with vary- ing background traffic loads, the proposed B.I.E.R.-based reliable multicast mechanism exhibits attractive performance attributes: it attains delivery success rates as high as any other reliable multicast service, but with significantly better link utilisation and no per-flow or per-group state in intermediate routers of the network.},
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This paper explores the use of B.I.E.R. as a basis for develop- ing an efficient and reliable multicast mechanism, where redun- dant traffic is avoided, essential traffic is forwarded along shortest paths, and no per-flow state is required in intermediate routers. Evaluated by way of both an analytical model and network sim- ulation both in generic and in real network topologies with vary- ing background traffic loads, the proposed B.I.E.R.-based reliable multicast mechanism exhibits attractive performance attributes: it attains delivery success rates as high as any other reliable multicast service, but with significantly better link utilisation and no per-flow or per-group state in intermediate routers of the network.
Desmouceaux, Yoann; Pfister, Pierre; Tollet, Jérôme; Townsley, W. Mark; Clausen, Thomas
6LB: Scalable and Application-Aware Load Balancing with Segment Routing Journal Article
In: IEEE/ACM Transactions on Networking, vol. 26, no. 2, pp. 819-834, 2018, ISSN: 1063-6692.
@article{Desmouceaux2018,
title = {6LB: Scalable and Application-Aware Load Balancing with Segment Routing},
author = {Yoann Desmouceaux and Pierre Pfister and Jérôme Tollet and W. Mark Townsley and Thomas Clausen},
url = {http://www.thomasclausen.net/wp-content/uploads/2018/02/2018-IEEE-Transactions-on-Networking-6LB-Scalable-and-Application-Aware-Load-Balancing-with-Segment-Routing.pdf},
doi = {10.1109/TNET.2018.2799242},
issn = {1063-6692},
year = {2018},
date = {2018-02-15},
urldate = {2018-02-15},
journal = {IEEE/ACM Transactions on Networking},
volume = {26},
number = {2},
pages = {819-834},
abstract = {Network load-balancers generally either do not take application state into account, or do so at the cost of a central- ized monitoring system. This paper introduces a load-balancer running exclusively within the IP forwarding plane, i.e. in an application protocol agnostic fashion – yet which still provides application-awareness and makes real-time, decentralized deci- sions. To that end, IPv6 Segment Routing is used to direct data packets from a new flow through a chain of candidate servers, until one decides to accept the connection, based solely on its local state. This way, applications themselves naturally decide on how to fairly share incoming connections, while incurring minimal network overhead, and no out-of-band signaling. A consistent hashing algorithm, as well as an in-band stickiness protocol, allow for the proposed solution to be able to be reliably distributed across a large number of instances.
Performance evaluation by means of an analytical model and actual tests on different workloads (including a Wikipedia replay as a realistic workload) show significant performance benefits in terms of shorter response times, when compared to a traditional random load-balancer. In addition, this paper introduces and compares kernel bypass high-performance implementations of both 6LB and a state-of-the-art load-balancer, showing that the significant system-level benefits of 6LB are achievable with a negligible data-path CPU overhead.},
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Performance evaluation by means of an analytical model and actual tests on different workloads (including a Wikipedia replay as a realistic workload) show significant performance benefits in terms of shorter response times, when compared to a traditional random load-balancer. In addition, this paper introduces and compares kernel bypass high-performance implementations of both 6LB and a state-of-the-art load-balancer, showing that the significant system-level benefits of 6LB are achievable with a negligible data-path CPU overhead.
2017
Clausen, Thomas; Yi, Jiazi; Herberg, Ulrich
Lightweight On-demand Ad hoc Distance-vector Routing-Next Generation (LOADng): Protocol, Extension, and Applicability Journal Article
In: Computer Networks, vol. 126, pp. 125-140, 2017.
@article{clausen2017lightweight,
title = {Lightweight On-demand Ad hoc Distance-vector Routing-Next Generation (LOADng): Protocol, Extension, and Applicability},
author = {Thomas Clausen and Jiazi Yi and Ulrich Herberg},
url = {http://www.thomasclausen.net/wp-content/uploads/2017/08/2017-Computer-Networks-Lightweight-On-demand-Ad-hoc-Distance-vector-Routing-Next-Generation-LOADng.pdf},
doi = {10.1016/j.comnet.2017.06.025},
year = {2017},
date = {2017-10-24},
journal = {Computer Networks},
volume = {126},
pages = {125-140},
publisher = {Elsevier},
abstract = {This paper studies the routing protocol “Lightweight On-demand Ad hoc Distance-vector Routing Protocol – Next Generation (LOADng)”, designed to enable efficient, scalable and secure routing in low power and lossy networks. As a reactive protocol, it does not maintain a routing table for all destinations in the network, but initiates a route discovery to a destination only when there is data to be sent to that destination to reduce routing overhead and memory consumption. Designed with a modular approach, LOADng can be extended with additional components for adapting the protocol to different topologies, traffic, and data-link layer characteristics. This paper studies several such additional components for extending LOADng: support for smart route requests and expanding ring search, an extension permitting maintaining collection trees, a fast rerouting extension. All those extensions are examined from the aspects of specification, interoperability with other mechanisms, security vulnerabilities, performance and applicability. A general framework is also proposed to secure the routing protocol.},
keywords = {},
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}
2016
Augustin, Aloys; Yi, Jiazi; Clausen, Thomas; Townsley, Mark
A Study of LoRa: Long Range & Low Power Networks for the Internet of Things Journal Article
In: MDPI Sensors, vol. 16, no. 9, pp. 1466, 2016, ISSN: 1424-8220, ((5 yr Impact Factor: 2.437)).
@article{Augustin2016,
title = {A Study of LoRa: Long Range & Low Power Networks for the Internet of Things},
author = {Aloys Augustin and Jiazi Yi and Thomas Clausen and Mark Townsley},
url = {http://www.thomasclausen.net/2016-a-study-of-lora-long-range-low-power-networks-for-the-internet-of-things/},
doi = {10.3390/s16091466},
issn = {1424-8220},
year = {2016},
date = {2016-09-09},
journal = {MDPI Sensors},
volume = {16},
number = {9},
pages = {1466},
abstract = {LoRa is a long-range, low-power, low-bitrate, wireless telecommunications system, promoted as an infrastructure solution for the Internet of Things: end-devices use LoRa across a single wireless hop to communicate to gateway(s), connected to the Internet and which act as transparent bridges and relay messages between these end-devices and a central network server. This paper provides an overview of LoRa and an in-depth analysis of its functional components. The physical and data link layer performance is evaluated by field tests and simulations. Based on the analysis and evaluations, some possible solutions for performance enhancements are proposed.},
note = {(5 yr Impact Factor: 2.437)},
keywords = {},
pubstate = {published},
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}
Cordero, Juan Antonio
Multi-Path TCP Performance Evaluation in Dual-Homed (Wired/Wireless) Devices Journal Article
In: Journal of Network and Computer Applications , vol. 70, pp. 131-139, 2016, ISSN: 1084-8045.
@article{Cordero2016,
title = {Multi-Path TCP Performance Evaluation in Dual-Homed (Wired/Wireless) Devices},
author = {Juan Antonio Cordero},
url = {https://www.epizeuxis.net/wp-content/uploads/2019/11/Multi-Path_TCP_Performance_Evaluation_in-1.pdf
http://www.sciencedirect.com/science/article/pii/S1084804516300819},
doi = {10.1016/j.jnca.2016.05.004},
issn = {1084-8045},
year = {2016},
date = {2016-07-01},
journal = {Journal of Network and Computer Applications },
volume = {70},
pages = {131-139},
abstract = {Multipath TCP is a major extension of TCP, designed for leveraging the increasing availability of multiple interfaces in end hosts, on one side, and the existence of diverse Internet paths between hosts, on the other. This paper proposes a measurement methodology and provides a first evaluation, based on real Internet experiments, of the user benefit of using MPTCP instead of TCP in devices with multiple wireless/wired networking interfaces. We focus on bandwidth utilization and file transfer delays. Our experiments, on a testbed with two disjoint paths connecting a server and a dual-homed probe, indicate that MPTCP is able, in most cases, to take advantage of additional bandwidth with limited cost in terms of delay, but also show that the MPTCP bandwidth benefit substantially degrades when the interfaces have very different bandwidth capacities.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2015
Yi, Jiazi; Clausen, Thomas; Herberg, Ulrich
Depth-First Forwarding for Unreliable Networks: Extensions and Application Journal Article
In: IEEE Internet of Things Journal, vol. 2015, no. 06, 2015.
@article{Yi2015,
title = {Depth-First Forwarding for Unreliable Networks: Extensions and Application},
author = {Jiazi Yi and Thomas Clausen and Ulrich Herberg},
url = {http://www.thomasclausen.net/wp-content/uploads/2015/12/2015-IEEE-Internet-of-Things-Journal-Depth-First-Forwarding-for-Unreliable-Networks-Extensions-and-Applications.pdf},
doi = {10.1109/JIOT.2015.2409892},
year = {2015},
date = {2015-05-25},
journal = {IEEE Internet of Things Journal},
volume = {2015},
number = {06},
abstract = {his paper introduces extensions and applications of depth-first forwarding (DFF)-a data forwarding mechanism for use in unreliable networks such as sensor networks and Mobile Ad hoc NETworks with limited computational power and storage, low-capacity channels, device mobility, etc. Routing protocols for these networks try to balance conflicting requirements of being reactive to topology and channel variation while also being frugal in resource requirements-but when the underlying topology changes, routing protocols require time to re converge, during which data delivery failure may occur. DFF was developed to alleviate this situation: it reacts rapidly to local data delivery failures and attempts to successfully deliver data while giving a routing protocol time to recover from such a failure. An extension of DFF, denoted as DFF++, is proposed in this paper, in order to optimize the performance of DFF by way of introducing a more efficient search ordering. This paper also studies the applicability of DFF to three major routing protocols for the Internet of Things (IoT), including the Lightweight On-demand Ad hoc Distance-vector Routing Protocol-Next Generation (LOADng), the optimized link state routing protocol version 2 (OLSRv2), and the IPv6 routing protocol for low-power and lossy networks (RPL), and presents the performance of these protocols, with and without DFF, in lossy and unreliable networks.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2014
Yi, Jiazi; Clausen, Thomas
Collection Tree Extension of Reactive Routing Protocol for Low-Power and Lossy Networks Journal Article
In: Hindawi International Journal of Distributed Sensor Networks, vol. 2014, no. Article ID 352421, pp. 12, 2014.
@article{Yi2014,
title = {Collection Tree Extension of Reactive Routing Protocol for Low-Power and Lossy Networks},
author = {Jiazi Yi and Thomas Clausen},
editor = {Christos Verikoukis},
url = {http://www.thomasclausen.net/wp-content/uploads/2015/12/2014-Hindawi-International-Journal-of-Distributed-Sensor-Networks-Collection-Tree-Extension-of-LOADng-Protocol-for-Low-power-and-Lossy-Networks.pdf},
doi = {doi:10.1155/2014/352421},
year = {2014},
date = {2014-03-25},
journal = {Hindawi International Journal of Distributed Sensor Networks},
volume = {2014},
number = {Article ID 352421},
pages = {12},
abstract = {This paper proposes an extension to reactive routing protocol, for efficient construction of a collection tree for data acquisition in sensor networks. The Lightweight On-Demand Ad hoc Distance Vector Routing Protocol-Next Generation (LOADng) is a reactive distance vector protocol which is intended for use in mobile ad hoc networks and low-power and lossy networks to build paths between source-destination pairs. In 2013, ITU-T has ratified the recommendation G.9903 Amendment 1, which includes LOADng in a specific normative annex for routing protocol in smart grids. The extension uses the mechanisms from LOADng, imposes minimal overhead and complexity, and enables a deployment to efficiently support “sensor-to-root” traffic, avoiding complications of unidirectional links in the collection tree. The protocol complexity, security, and interoperability are examined in detail. The simulation results show that the extension can effectively improve the efficiency of data acquisition in the network.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Cordero, Juan Antonio; Yi, Jiazi; Clausen, Thomas
An Adaptive Jitter Mechanism for Reactive Route Discovery in Sensor Networks Journal Article
In: Sensors, vol. 14, no. 8, pp. 14440, 2014, ISSN: 1424-8220, (http://www.mdpi.com/1424-8220/14/8/14440).
@article{s140814440,
title = {An Adaptive Jitter Mechanism for Reactive Route Discovery in Sensor Networks},
author = {Juan Antonio Cordero and Jiazi Yi and Thomas Clausen},
url = {http://www.thomasclausen.net/wp-content/uploads/2015/12/2014-MDPI-Sensors-An-Adaptive-Jitter-Mechanism-for-Reactive-Route-Discovery-in-Sensor-Networks.pdf},
doi = {10.3390/s140814440},
issn = {1424-8220},
year = {2014},
date = {2014-01-01},
journal = {Sensors},
volume = {14},
number = {8},
pages = {14440},
abstract = {This paper analyses the impact of jitter when applied to route discovery in reactive (on-demand) routing protocols. In multi-hop non-synchronized wireless networks, jitter—a small, random variation in the timing of message emission—is commonly employed, as a means to avoid collisions of simultaneous transmissions by adjacent routers over the same channel. In a reactive routing protocol for sensor and ad hoc networks, jitter is recommended during the route discovery process, specifically, during the network-wide flooding of route request messages, in order to avoid collisions. Commonly, a simple uniform jitter is recommended. Alas, this is not without drawbacks: when applying uniform jitter to the route discovery process, an effect called delay inversion is observed. This paper, first, studies and quantifies this delay inversion effect. Second, this paper proposes an adaptive jitter mechanism, designed to alleviate the delay inversion effect and thereby to reduce the route discovery overhead and (ultimately) allow the routing protocol to find more optimal paths, as compared to uniform jitter. This paper presents both analytical and simulation studies, showing that the proposed adaptive jitter can effectively decrease the cost of route discovery and increase the path quality.},
note = {http://www.mdpi.com/1424-8220/14/8/14440},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2013
Cordero, Juan Antonio
A Probabilistic Study of the Delay caused by Jittering in Wireless Flooding Journal Article
In: Wireless Personal Communications, vol. 73, no. 3, pp. 415-439, 2013, ISSN: 0929-6212.
@article{Cordero2013-WPC,
title = {A Probabilistic Study of the Delay caused by Jittering in Wireless Flooding},
author = {Juan Antonio Cordero},
url = {http://link.springer.com/article/10.1007%2Fs11277-013-1195-8},
doi = {10.1007/s11277-013-1195-8},
issn = {0929-6212},
year = {2013},
date = {2013-05-01},
journal = {Wireless Personal Communications},
volume = {73},
number = {3},
pages = {415-439},
abstract = {Systematic packet collisions constitute a major problem in wireless flooding, which is a key mechanism for information dissemination in wireless mesh and multi-hop ad hoc networks. Since this cannot be solved only through classic MAC collision avoidance mechanisms, the IETF has proposed and standardized in RFC 5148 jittering techniques to handle it. These techniques are widely used in protocols for wireless communication such as OLSR, AODV or LOAD, and have proven useful for reducing collisions. They lead however some undesirableside effects that may harm substantially the flooding performance. To the best of our knowledge, no research effort has been deployed to understand and analyze these effects. This paper addresses this issue. It motivates and introduces a theoretical model of flooding with jitter in a wireless interface, as specified in RFC 5148, and explores the probabilistic characterization of additional flooding delay caused by jitter. It mostly provides two analytical bounds for the per-interface additional jitter delay. Presented results, which are validated by way of a discrete-event simulation, enable a better understanding of the performance trade-offs (between packet collisions and additional delay, in particular) underlying the use of jitter in wireless flooding.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2011
Herberg, Ulrich; Clausen, Thomas
Study of Multipoint-to-Point and Broadcast Traffic Performance in the 'IPv6 Routing Protocol for Low Power and Lossy Networks' (RPL) Journal Article
In: Journal of Ambient Intelligence and Humanized Computing, Springer, ISSN 1868-5137, Volume 2, Number 4, 2011, (http://link.springer.com/article/10.1007/s12652-011-0046-2).
@article{LIX-NET-journal-119,
title = {Study of Multipoint-to-Point and Broadcast Traffic Performance in the 'IPv6 Routing Protocol for Low Power and Lossy Networks' (RPL)},
author = {Ulrich Herberg and Thomas Clausen},
url = {http://www.thomasclausen.net/wp-content/uploads/2015/12/2011-Journal-of-Ambient-Intelligence-and-Humanized-Computing-Study-of-Multipoint-to-Point-and-Broadcast-Traffic-Performance-in-the-IPv6-Routing-Protocol-for-Low-Power-and-Lossy-Networks-RPL.pdf},
year = {2011},
date = {2011-10-01},
journal = {Journal of Ambient Intelligence and Humanized Computing, Springer, ISSN 1868-5137, Volume 2, Number 4},
abstract = {Recent trends in Wireless Sensor Networks (WSNs) have suggested converging to such being IPv6-based. To this effect, the Internet Engineering Task Force has chartered a Working Group to develop a routing protocol specification, enabling IPv6-based multi-hop Wireless Sensor Networks. This routing protocol, denoted “IPv6 Routing Protocol for Low Power and Lossy Networks” (RPL), has been under development for approximately a year, and this paper takes a critical look at the state of advancement hereof: it provides a brief algorithmic description of the protocol, and discusses areas where—in the authors view—further efforts are required in order for the protocol to become a viable candidate for general use in WSNs. Among these areas is the lack of a proper broadcast mechanism. This paper suggests several such broadcast mechanisms, all aiming at (1) exploiting the existing routing state of RPL, while (2) requiring no additional state maintenance, and studies the performance of RPL and of these suggested mechanisms.},
note = {http://link.springer.com/article/10.1007/s12652-011-0046-2},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2010
Cordero, Juan Antonio; Baccelli, Emmanuel; Jacquet, Philippe
OSPF over Multi-Hop Ad Hoc Wireless Communications Journal Article
In: International Journal of Computer Networks and Communications , vol. 2, no. 5, pp. 38-56, 2010, ISSN: 0975-2293.
@article{Fuertes2010-IJCNC,
title = {OSPF over Multi-Hop Ad Hoc Wireless Communications},
author = {Juan Antonio Cordero and Emmanuel Baccelli and Philippe Jacquet},
url = {http://airccse.org/journal/cnc/0910ijcnc03.pdf},
issn = {0975-2293},
year = {2010},
date = {2010-09-01},
journal = {International Journal of Computer Networks and Communications },
volume = {2},
number = {5},
pages = {38-56},
abstract = {Efficient OSPF (Open Shortest Path First) operation on multi-hop ad hoc wireless networks has become desirable, as wireless community mesh networks and vehicular networks emerge using OLSR (Optimized Link State Routing), a link state MANET routing protocol similar to OSPF in many aspects. OSPF is already extensively deployed and well known in wired IP networks, and could provide simple, seamless unification of wired and wireless IP networking routing-wise, if extended to operate efficiently on ad hoc networks. The IETF has thus proposed three different MANET extensions to the OSPF protocol, allowing heterogeneous networks encompassing both wired and wireless routers, which may self-organize as multi-hop wireless subnetworks, and be mobile. Two of these extensions are based on techniques derived from multi-point relaying (MPR). In the following, we compare and analyze these two extensions and we propose a unique, merged approach which out-performs the existing extensions.
},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Herberg, Ulrich; Clausen, Thomas
Security Issues in the Optimized Link State Routing Protocol Version 2 (OLSRV2) Journal Article
In: International Journal of Network Security & Its Applications (IJNSA), 2010.
@article{LIX-NET-journal-70,
title = {Security Issues in the Optimized Link State Routing Protocol Version 2 (OLSRV2)},
author = {Ulrich Herberg and Thomas Clausen},
url = {http://www.thomasclausen.net/wp-content/uploads/2015/12/2010-IJNSA-Security-Issues-in-the-Optimized-Link-State-Routing-Protocol-version-2-OLSRv2-1.pdf},
year = {2010},
date = {2010-04-01},
journal = {International Journal of Network Security & Its Applications (IJNSA)},
abstract = {Mobile Ad hoc NETworks (MANETs) are leaving the confines of research laboratories, to find place in real-world deployments. Outside specialized domains (military, vehicular, etc.), city-wide community- networks are emerging, connecting regular Internet users with each other, and with the Internet, via MANETs. Growing to encompass more than a handful of “trusted participants”, the question of preserving the MANET network connectivity, even when faced with careless or malicious participants, arises, and must be addressed. A first step towards protecting a MANET is to analyze the vulnerabilities of the routing protocol, managing the connectivity. By understanding how the algorithms of the routing protocol operate, and how these can be exploited by those with ill intent, countermeasures can be developed, readying MANETs for wider deployment and use. This paper takes an abstract look at the algorithms that constitute the Optimized Link State Routing Protocol version 2 (OLSRv2), and identifies for each protocol element the possible vulnerabilities and attacks – in a certain way, provides a “cookbook” for how to best attack an operational OLSRv2 network, or for how to proceed with developing protective countermeasures against these attacks.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2004
Clausen, Thomas; Baccelli, Emmanuel; Rodolakis, Georgios; Adjih, Cedric; Jacquet, Philippe
Fish-Eye OLSR Scaling Properties Journal Article
In: IEEE Journal on Communications Networks (JCN), Special Issue on Ad Hoc Networking, Dec 2004, 2004.
@article{LIX-NET-journal-2,
title = {Fish-Eye OLSR Scaling Properties},
author = {Thomas Clausen and Emmanuel Baccelli and Georgios Rodolakis and Cedric Adjih and Philippe Jacquet},
url = {http://www.thomasclausen.net/wp-content/uploads/2015/12/2004-JCN-Fish-Eye-OLSR-Scaling-Properties.pdf},
year = {2004},
date = {2004-12-01},
journal = {IEEE Journal on Communications Networks (JCN), Special Issue on Ad Hoc Networking, Dec 2004},
abstract = {Scalability is one of the toughest challenges in ad hoc networking. Recent work outlines theoretical bounds on how well routing protocols could scale in this environment. However, none of the popular routing solutions really scales to large networks, by coming close enough to these bounds. In this paper, we study the case of link state routing and OLSR, one of the strongest candidate for standardization. We analyze how these bounds are not reached in this case, and we study how much the scalability is enhanced with the use of Fish Eye techniques in addition to the link state routing framework. We show that with this enhancement, the theoretical scalability bounds are reached.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Clausen, Thomas; Jacquet, Philippe; Viennot, Laurent
Analyzing Control Traffic Overhead versus Mobility and Data Traffic Activity in Mobile Ad Hoc Network Protocols Journal Article
In: ACM Journal on Wireless Networks (Winet) July 2004, volume 10 no. 4, 2004.
@article{Clausen2004,
title = {Analyzing Control Traffic Overhead versus Mobility and Data Traffic Activity in Mobile Ad Hoc Network Protocols},
author = {Thomas Clausen and Philippe Jacquet and Laurent Viennot},
url = {http://www.thomasclausen.net/wp-content/uploads/2015/12/2004-ACM-WINET-Analyzing-Control-Traffic-Overhead-versus-Mobility-and-Data-Traffic-Activity-in-Mobile-Ad-hoc-Network-Protoc.pdf},
year = {2004},
date = {2004-07-01},
journal = {ACM Journal on Wireless Networks (Winet) July 2004, volume 10 no. 4},
abstract = {This paper proposes a general, parameterized model for analyzing protocol control overhead in mobile ad-hoc networks. A probabilistic model for the network topology and the data traffic is proposed in order to estimate overhead due to control packets of routing protocols. Our analytical model is validated by comparisons with simulations, both taken from literature and made specifically for this paper. For example, our model predicts linearity of control overhead with regard to mobility as observed in existing simulations results. We identify the model parameters for protocols like AODV, DSR and OLSR. Our model then allows accurate predictions of which protocol will yield the lowest overhead depending on the node mobility and traffic activity pattern.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}