The paper proposes an analytical model to evaluate the collision probability on the Random-Access... more The paper proposes an analytical model to evaluate the collision probability on the Random-Access CHannel (RACH) in LTE systems as a function of the number of User Equipments (UEs), the number of available preambles and the Inter-arrival times of the RACH Requests (IRR) of the average user. The model for the IRR of the average user is obtained from real traffic data captured at the eNodeB of a mobile operator, and is derived by emulating the RRC state machine for different Radio Resource Control Inactivity Timer (RRC IT) settings. The results of the presented study suggest that when RRC IT is set to a few seconds a mixture model is more accurate than the Poisson hypothesis both in modelling the IRR and in estimating the RACH performance.
The LHCb DAQ Network is a real time high performance network, in which 350 data sources send data... more The LHCb DAQ Network is a real time high performance network, in which 350 data sources send data over a Gigabit Ethernet LAN to more than 1500 receiving nodes. The aggregated throughput of the application, called Event Building, is more than 60 Gbps. The protocol employed by LHCb makes the sending nodes transmit simultaneously portions of events to one receiving node at a time, which is selected using a credit-token scheme. The resulting traffic is very bursty and sensitive to irregularities in the temporal distribution of packet-bursts to the same destination or region of the network. In order to study the relevant properties of such a dataflow, a non-disruptive monitoring setup based on a networking capable FPGA (Netfpga) has been deployed. The Netfpga allows order of hundred nano-second precise time-stamping of packets. We study in detail the timing structure of the Event Building communication, and we identify potential effects of micro-bursts like buffer packet drops or jitter.
... Jane Klobas* Graduate School of Management University of Western Australia 35 Stirling Hwy, N... more ... Jane Klobas* Graduate School of Management University of Western Australia 35 Stirling Hwy, Nedlands 6909, Australia jklobas@ecel.uwa.edu.au tel: +61 8 9380 3980; fax: +61 8 9380 1072 *also at Bocconi University Stefano Renzi Istituto Metodi Quantitativi Bocconi ...
The maturity level reached by today’s commodity platforms makes even low-cost PCs viable alternat... more The maturity level reached by today’s commodity platforms makes even low-cost PCs viable alternatives to dedicated hardware to implement real network functions without sacrificing performance. Indeed, the availability of multi-core processing packages and multi-queue network interfaces that can be managed by accelerated I/O frameworks, provides off-the-shelf servers with the necessary power capability for running a broad variety of network applications with near hardware-class performance. At the same time, the introduction of the Software Defined Networks (SDN) and the Network Functions Virtualization (NFV) paradigms call for new programming abstractions and tools to allow this new class of network devices to be flexibly configured and functionally repurposed from the network control plane. The paper presents the ongoing work towards Enif-Lang (Enhanced Network processIng Functional Language), a functional language for programming network functions over generic middleboxes running ...
IEEE Transactions on Network and Service Management, 2019
The IEEE Taxonomy comprises the first three hierarchical 'levels' under each term-family (or bran... more The IEEE Taxonomy comprises the first three hierarchical 'levels' under each term-family (or branch) that is formed from the top-most terms of the IEEE Thesaurus. In this document these term-families are arranged alphabetically and denoted by boldface type. Each term family's hierarchy goes to no more than three sublevels, denoted by indents (in groups of four dots) preceding the next level terms. A term can appear in more than one hierarchical branch and can appear more than once in any particular hierarchy. The IEEE Taxonomy is defined in this way so that it is always a subset of the 2017 IEEE Thesaurus.
This article describes the current evolution of QoS architectures, mechanisms, and protocols in t... more This article describes the current evolution of QoS architectures, mechanisms, and protocols in the Internet, as it is ongoing in the framework of the European Union funded research projects on premium IP networks. A short review of the proposed standard approaches to QoS (e.g., differentiated services, integrated services, and label switching technologies) is given. Then we focus on the state-of-the-art architectures, mainly based on DiffServ concepts. Several issues arise when trying to implement these architectures in the real world: QoS aspects, network monitoring of the offered QoS, and end-user control of received QoS. The article then discusses the existing results and the current direction of European research and development in these areas.
2019 IEEE 24th International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD)
The introduction of the Cloud paradigm has rapidly changed IT-infrastructures in modern organizat... more The introduction of the Cloud paradigm has rapidly changed IT-infrastructures in modern organizations. The application of Cloud systems to manage a growing number of IoT devices such as sensors is continually unfolding and revealing new opportunities. A notable field of research is related to the development of models, applications and real testbed on robots that can be managed and coordinated remotely at a higher layer involving network communications. In this paper, we present Open CLORO: an open testbed for Cloud robotics. We propose Open CLORO, which serves as a benchmark for real experiments for various network applications in which the Robots are equipped with programmable devices that also provide network connectivity and grant access from remote. We provide a detailed overview of the proposed architecture that can be effective for developing and testing not only robots-related experiments but also a wide number of network applications such as distributed coordination, vehicle-to-vehicle communications, and Cloud-based management services.
2021 IEEE 26th International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD)
Evaluating the performance of LoRa in different operating conditions, especially when LoRa is ado... more Evaluating the performance of LoRa in different operating conditions, especially when LoRa is adopted as communication technology for enabling applications in rural environments, is a key challenge. LoRa performance is affected by the values assigned to several parameters, such as the Spreading Factor (SF), the Code Rate (CR), etc. To this purpose, at first, we designed and implemented a flexible, user-friendly, and easy to program Lora packet generator. Then, we investigated the performance of LoRa in light-dense and very-dense forest vegetation environments when the distance between the transmitter and the receiver varies. This study aimed at highlighting how such performance is related to different LoRa settings when operating in the 433 MHz and 868 MHz bands. Focusing on the link quality and transmission performance, we conducted both a theoretical study and a massive measurements campaign in a field trial deployed in an Italian natural park. Results help find the best LoRa configuration parameters when operating in light-dense or very-dense forest environments.
Time Slotted Channel Hopping (TSCH), defined among the operating modes in IEEE 802.15.4-2015 stan... more Time Slotted Channel Hopping (TSCH), defined among the operating modes in IEEE 802.15.4-2015 standard, was established to offer a guaranteed quality of service for deterministic industrial type applications. However, the standard only provides a framework but it does not mandate a specific scheduling mechanism. In this paper, we formulate the NP-hard scheduling problem in terms of maximizing the throughput with deadline constraints and at the same time satisfying interference constraints in TSCH Networks. In the considered TSCH network, a centralized entity typically called gateway, coordinates the assignment of frequencies and timeslots to the nodes. To solve this NP-hard throughput scheduling problem, a Genetic Algorithm (GA) framework was adopted. Simulation results corroborate that our GA-based approach yields very close performance to the optimal solutions and operates with much lower complexity. In addition, the results also confirmed that GA outperforms other popular scheduling algorithms in the literature in terms of throughput maximization as well minimizing violated deadlines.
2016 International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS), 2016
Sensing, computing and communication are the main features of a wireless sensor network (WSN) whi... more Sensing, computing and communication are the main features of a wireless sensor network (WSN) which serves a wide range of applications. Despite its versatility and simplicity, it brought up various challenges such as limited storage, power consumption from radio activities, just to mention a few. The distinguishing traits of sensor networks have a direct impact on their protocol design at each layer, especially at the Medium Access Control (MAC) layer since it manages transmission scheduling as well as duty cycling for energy conservation. To maximize energy efficiency of WSNs, a critical analysis of the radio duty cycle of the WSN operating systems were carried out with experimental evaluation. Moreover, we focus on the energy consumption by conducting experimental measurements on different platforms i.e. OpenMote-CC2538 on various operating systems. Results shows that IEEE 802.15.4e Time Synchronized Channel Hopping (TSCH) has great impact on the energy consumption with respect to other radio duty cycles.
The paper proposes an analytical model to evaluate the collision probability on the Random-Access... more The paper proposes an analytical model to evaluate the collision probability on the Random-Access CHannel (RACH) in LTE systems as a function of the number of User Equipments (UEs), the number of available preambles and the Inter-arrival times of the RACH Requests (IRR) of the average user. The model for the IRR of the average user is obtained from real traffic data captured at the eNodeB of a mobile operator, and is derived by emulating the RRC state machine for different Radio Resource Control Inactivity Timer (RRC IT) settings. The results of the presented study suggest that when RRC IT is set to a few seconds a mixture model is more accurate than the Poisson hypothesis both in modelling the IRR and in estimating the RACH performance.
The LHCb DAQ Network is a real time high performance network, in which 350 data sources send data... more The LHCb DAQ Network is a real time high performance network, in which 350 data sources send data over a Gigabit Ethernet LAN to more than 1500 receiving nodes. The aggregated throughput of the application, called Event Building, is more than 60 Gbps. The protocol employed by LHCb makes the sending nodes transmit simultaneously portions of events to one receiving node at a time, which is selected using a credit-token scheme. The resulting traffic is very bursty and sensitive to irregularities in the temporal distribution of packet-bursts to the same destination or region of the network. In order to study the relevant properties of such a dataflow, a non-disruptive monitoring setup based on a networking capable FPGA (Netfpga) has been deployed. The Netfpga allows order of hundred nano-second precise time-stamping of packets. We study in detail the timing structure of the Event Building communication, and we identify potential effects of micro-bursts like buffer packet drops or jitter.
... Jane Klobas* Graduate School of Management University of Western Australia 35 Stirling Hwy, N... more ... Jane Klobas* Graduate School of Management University of Western Australia 35 Stirling Hwy, Nedlands 6909, Australia jklobas@ecel.uwa.edu.au tel: +61 8 9380 3980; fax: +61 8 9380 1072 *also at Bocconi University Stefano Renzi Istituto Metodi Quantitativi Bocconi ...
The maturity level reached by today’s commodity platforms makes even low-cost PCs viable alternat... more The maturity level reached by today’s commodity platforms makes even low-cost PCs viable alternatives to dedicated hardware to implement real network functions without sacrificing performance. Indeed, the availability of multi-core processing packages and multi-queue network interfaces that can be managed by accelerated I/O frameworks, provides off-the-shelf servers with the necessary power capability for running a broad variety of network applications with near hardware-class performance. At the same time, the introduction of the Software Defined Networks (SDN) and the Network Functions Virtualization (NFV) paradigms call for new programming abstractions and tools to allow this new class of network devices to be flexibly configured and functionally repurposed from the network control plane. The paper presents the ongoing work towards Enif-Lang (Enhanced Network processIng Functional Language), a functional language for programming network functions over generic middleboxes running ...
IEEE Transactions on Network and Service Management, 2019
The IEEE Taxonomy comprises the first three hierarchical 'levels' under each term-family (or bran... more The IEEE Taxonomy comprises the first three hierarchical 'levels' under each term-family (or branch) that is formed from the top-most terms of the IEEE Thesaurus. In this document these term-families are arranged alphabetically and denoted by boldface type. Each term family's hierarchy goes to no more than three sublevels, denoted by indents (in groups of four dots) preceding the next level terms. A term can appear in more than one hierarchical branch and can appear more than once in any particular hierarchy. The IEEE Taxonomy is defined in this way so that it is always a subset of the 2017 IEEE Thesaurus.
This article describes the current evolution of QoS architectures, mechanisms, and protocols in t... more This article describes the current evolution of QoS architectures, mechanisms, and protocols in the Internet, as it is ongoing in the framework of the European Union funded research projects on premium IP networks. A short review of the proposed standard approaches to QoS (e.g., differentiated services, integrated services, and label switching technologies) is given. Then we focus on the state-of-the-art architectures, mainly based on DiffServ concepts. Several issues arise when trying to implement these architectures in the real world: QoS aspects, network monitoring of the offered QoS, and end-user control of received QoS. The article then discusses the existing results and the current direction of European research and development in these areas.
2019 IEEE 24th International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD)
The introduction of the Cloud paradigm has rapidly changed IT-infrastructures in modern organizat... more The introduction of the Cloud paradigm has rapidly changed IT-infrastructures in modern organizations. The application of Cloud systems to manage a growing number of IoT devices such as sensors is continually unfolding and revealing new opportunities. A notable field of research is related to the development of models, applications and real testbed on robots that can be managed and coordinated remotely at a higher layer involving network communications. In this paper, we present Open CLORO: an open testbed for Cloud robotics. We propose Open CLORO, which serves as a benchmark for real experiments for various network applications in which the Robots are equipped with programmable devices that also provide network connectivity and grant access from remote. We provide a detailed overview of the proposed architecture that can be effective for developing and testing not only robots-related experiments but also a wide number of network applications such as distributed coordination, vehicle-to-vehicle communications, and Cloud-based management services.
2021 IEEE 26th International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD)
Evaluating the performance of LoRa in different operating conditions, especially when LoRa is ado... more Evaluating the performance of LoRa in different operating conditions, especially when LoRa is adopted as communication technology for enabling applications in rural environments, is a key challenge. LoRa performance is affected by the values assigned to several parameters, such as the Spreading Factor (SF), the Code Rate (CR), etc. To this purpose, at first, we designed and implemented a flexible, user-friendly, and easy to program Lora packet generator. Then, we investigated the performance of LoRa in light-dense and very-dense forest vegetation environments when the distance between the transmitter and the receiver varies. This study aimed at highlighting how such performance is related to different LoRa settings when operating in the 433 MHz and 868 MHz bands. Focusing on the link quality and transmission performance, we conducted both a theoretical study and a massive measurements campaign in a field trial deployed in an Italian natural park. Results help find the best LoRa configuration parameters when operating in light-dense or very-dense forest environments.
Time Slotted Channel Hopping (TSCH), defined among the operating modes in IEEE 802.15.4-2015 stan... more Time Slotted Channel Hopping (TSCH), defined among the operating modes in IEEE 802.15.4-2015 standard, was established to offer a guaranteed quality of service for deterministic industrial type applications. However, the standard only provides a framework but it does not mandate a specific scheduling mechanism. In this paper, we formulate the NP-hard scheduling problem in terms of maximizing the throughput with deadline constraints and at the same time satisfying interference constraints in TSCH Networks. In the considered TSCH network, a centralized entity typically called gateway, coordinates the assignment of frequencies and timeslots to the nodes. To solve this NP-hard throughput scheduling problem, a Genetic Algorithm (GA) framework was adopted. Simulation results corroborate that our GA-based approach yields very close performance to the optimal solutions and operates with much lower complexity. In addition, the results also confirmed that GA outperforms other popular scheduling algorithms in the literature in terms of throughput maximization as well minimizing violated deadlines.
2016 International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS), 2016
Sensing, computing and communication are the main features of a wireless sensor network (WSN) whi... more Sensing, computing and communication are the main features of a wireless sensor network (WSN) which serves a wide range of applications. Despite its versatility and simplicity, it brought up various challenges such as limited storage, power consumption from radio activities, just to mention a few. The distinguishing traits of sensor networks have a direct impact on their protocol design at each layer, especially at the Medium Access Control (MAC) layer since it manages transmission scheduling as well as duty cycling for energy conservation. To maximize energy efficiency of WSNs, a critical analysis of the radio duty cycle of the WSN operating systems were carried out with experimental evaluation. Moreover, we focus on the energy consumption by conducting experimental measurements on different platforms i.e. OpenMote-CC2538 on various operating systems. Results shows that IEEE 802.15.4e Time Synchronized Channel Hopping (TSCH) has great impact on the energy consumption with respect to other radio duty cycles.
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Papers by Stefano Giordano