Fractal or scaling phenomena, such as self-similarity and long-range dependence, have been detect... more Fractal or scaling phenomena, such as self-similarity and long-range dependence, have been detected in network traffic, with important implications for network performance. This paper describes how the characteristics of traffic change when it traverses IEEE 802.11 ...
2006 IEEE 17th International Symposium on Personal, Indoor and Mobile Radio Communications, 2006
Several fractal or scaling phenomena, such as self-similarity and long-range dependence, have bee... more Several fractal or scaling phenomena, such as self-similarity and long-range dependence, have been detected in network traffic, with important implications for network performance. In this paper we describe a detailed study that assesses how the characteristics of traffic change when it traverses IEEE 802.11 networks. Various scenarios, including the hidden node situation and the effect of relaying, have been simulated. The simpler scenario has also been replicated in a real testbed, in order to corroborate the results obtained in the simulations. The most significant results are the smoothing effect of the MAC mechanisms on the traffic at the highest frequencies, while at the lowest frequencies we find a mitigation of fractality that seems to be caused by packet loss induced by propagation impairments. The overall effect is a mitigation of fractal characteristics on the output traffic.
ABSTRACT The increasing awareness of the impact of the IT sector on the environment, together wit... more ABSTRACT The increasing awareness of the impact of the IT sector on the environment, together with economic factors, have fueled many research efforts to reduce the energy expenditure of data centers. Recent work proposes to achieve additional energy savings by exploiting, in concert with customers, services’ workloads and to reduce data centers’ carbon footprints by adopting demand-response mechanisms between data centers and their energy providers. In this paper, we debate about the incentives that customers and data centers should have to adopt such measures and propose a new service type and pricing scheme that is economically attractive and technically realizable. Simulation results based on real measurements confirm that our scheme can achieve additional energy savings while preserving service performance.
Future metropolitan and access networks are expected to comprise heterogeneous optical and broadb... more Future metropolitan and access networks are expected to comprise heterogeneous optical and broadband wireless technologies. The growing demand of users for transparent, ubiquitous access to diverse communication services poses several challenges. We envision a future metro-access architecture that comprises Optical Burst Switching networks that feed Ethernet Passive Optical Networks (PON) or upcoming Wavelength-Division Multiplexing PON, which in turn feed IEEE 802.16 and IEEE 802.11 nodes. Nodes in the wireless realm may communicate in a multihop fashion, forming mesh networks. To maintain cost and resource efficiency, we propose the introduction of Quality of Service (QoS) proxies at the border between different link technologies. These entities handle QoS requirements and aid to the support of mobility. The architecture requires no modification of the Medium Access Control mechanisms of the different technologies. Index Terms-Optical fiber communication, mobile communication, metropolitan area networks.
We propose a new protocol, named DS-SWAN (Differentiated Services-Stateless Wireless Ad Hoc Netwo... more We propose a new protocol, named DS-SWAN (Differentiated Services-Stateless Wireless Ad Hoc Networks), to support end-to-end Quality of Service (QoS) in ad hoc networks connected to a fixed DiffServ domain. When congestion is excessive for the correct functioning of real-time applications, DS-SWAN determines the source of the problem, warns the nodes in the ad hoc network if it is the case and the nodes react by slowing down best-effort traffic. Furthermore, we present an associated routing protocol for the ad hoc network in this context, named SD-AODV (Service Differentiation-Ad Hoc On-Demand Distance Vector), where new route requests are suppressed at certain nodes to maintain the desired QoS requirements for real-time flows. A simulation study is presented for the case when traffic is sent from the ad hoc network towards the fixed network as well as in the opposite direction. The scalability of DS-SWAN with respect to the network size, number of real-time traffic sources, node mobility and best-effort traffic load is analyzed. Simulation results indicate that DS-SWAN and SD-AODV significantly improve end-to-end delays and jitter for real-time flows without starvation of background traffic.
Proceedings of the 7th ACM international symposium on Modeling, analysis and simulation of wireless and mobile systems - MSWiM '04, 2004
... MC Domingo Telematics Eng. ... 1. INTRODUCTION Several authors have presented proposals to su... more ... MC Domingo Telematics Eng. ... 1. INTRODUCTION Several authors have presented proposals to support QoS (Quality of Service) in isolated ad hoc networks, including QoS oriented MAC protocols [1], QoS aware routing protocols [2] and resource reservation protocols such as ...
This paper analyzes the provision of end-to-end Quality of Service between nodes in a mobile ad h... more This paper analyzes the provision of end-to-end Quality of Service between nodes in a mobile ad hoc network and a fixed IP network that supports Differentiated Services. The ad hoc network incorporates the Stateless Wireless Ad Hoc Networks (SWAN) model to perform admission control for real-time traffic flows. We propose a new protocol, named DS-SWAN (Differentiated Services-SWAN), where end-to-end delays and loss rates of real-time traffic are monitored continuously at the destination nodes in the fixed network and at the edge routers respectively. In this way, nodes in the ad hoc network are warned when congestion is excessive for the correct functioning of a real-time application (specifically, Variable Bit Rate Voice-over-IP), so that the nodes restrain best-effort traffic in order to favour real-time flows. The results indicate that DS-SWAN significantly improves end-to-end delays without starvation of background traffic, adapting itself to changing traffic and network conditions in a relatively small ad hoc network. Besides, we compare different notification procedures in DS-SWAN aimed to improve scalability.
... We have evaluated and compared the performance of a Page 9. 82 MC Domingo and D. Remondo Fig.... more ... We have evaluated and compared the performance of a Page 9. 82 MC Domingo and D. Remondo Fig. ... However, each node calculates the average MAC delays during the simulation. Fig. 5 represents the average end-to-end delays for VoIP. ...
Proceedings - Advanced Industrial Conference on Telecommunications/Service Assurance with Partial and Intermittent Resources Conference/E-Learning on Telecommunications Workshop AICT/SAPIR/ELETE 2005, 2005
We propose a new protocol, named DS-SWAN (Differentiated Services-Stateless Wireless Ad Hoc Netwo... more We propose a new protocol, named DS-SWAN (Differentiated Services-Stateless Wireless Ad Hoc Networks), to support end-to-end QoS (Quality of Service) in ad hoc networks connected to fixed DiffServ domains. DS-SWAN warns nodes in the ad hoc network when congestion is excessive for the correct functioning of real-time applications. These nodes react by slowing down best-effort traffic. Furthermore, we present a routing protocol for the ad hoc network, named SD-AODV (Service Differentiation-Ad Hoc On-demand Distance Vector), where new route requests are suppressed at certain nodes to maintain the desired QoS requirements for real-time flows. Simulation results indicate that DS-SWAN and SD-AODV significantly improve end-to-end delays for real-time flows without starvation of background traffic. In this work we also present several versions of the SD-AODV routing protocol and study their behaviour.
International Journal of Wireless and Mobile Computing, 2010
... Garg, S., Kappes, M. and Trivedi, KS (2002a) Supporting VoIP Traffic in IEEE 802.11 WLAN with... more ... Garg, S., Kappes, M. and Trivedi, KS (2002a) Supporting VoIP Traffic in IEEE 802.11 WLAN with Enhanced Medium Access Control (MAC) for Quality of Service, www.research.avayalabs.com/ techreport/ALR-2002-025-paper.pdf Domingo, MC and Remondo, D. (2004) 'Quality ...
... we modified the DSR protocol and created a new version that is named SEADSR (Simple Energy Aw... more ... we modified the DSR protocol and created a new version that is named SEADSR (Simple Energy Aware DSR). In this work we have run simulations of DSR and SEADSR using IEEE 802.11b as link layer. ... The second section explains the basic functioning of the DSR protocol. ...
Fractal or scaling phenomena, such as self-similarity and long-range dependence, have been detect... more Fractal or scaling phenomena, such as self-similarity and long-range dependence, have been detected in network traffic, with important implications for network performance. This paper describes how the characteristics of traffic change when it traverses IEEE 802.11 ...
2006 IEEE 17th International Symposium on Personal, Indoor and Mobile Radio Communications, 2006
Several fractal or scaling phenomena, such as self-similarity and long-range dependence, have bee... more Several fractal or scaling phenomena, such as self-similarity and long-range dependence, have been detected in network traffic, with important implications for network performance. In this paper we describe a detailed study that assesses how the characteristics of traffic change when it traverses IEEE 802.11 networks. Various scenarios, including the hidden node situation and the effect of relaying, have been simulated. The simpler scenario has also been replicated in a real testbed, in order to corroborate the results obtained in the simulations. The most significant results are the smoothing effect of the MAC mechanisms on the traffic at the highest frequencies, while at the lowest frequencies we find a mitigation of fractality that seems to be caused by packet loss induced by propagation impairments. The overall effect is a mitigation of fractal characteristics on the output traffic.
ABSTRACT The increasing awareness of the impact of the IT sector on the environment, together wit... more ABSTRACT The increasing awareness of the impact of the IT sector on the environment, together with economic factors, have fueled many research efforts to reduce the energy expenditure of data centers. Recent work proposes to achieve additional energy savings by exploiting, in concert with customers, services’ workloads and to reduce data centers’ carbon footprints by adopting demand-response mechanisms between data centers and their energy providers. In this paper, we debate about the incentives that customers and data centers should have to adopt such measures and propose a new service type and pricing scheme that is economically attractive and technically realizable. Simulation results based on real measurements confirm that our scheme can achieve additional energy savings while preserving service performance.
Future metropolitan and access networks are expected to comprise heterogeneous optical and broadb... more Future metropolitan and access networks are expected to comprise heterogeneous optical and broadband wireless technologies. The growing demand of users for transparent, ubiquitous access to diverse communication services poses several challenges. We envision a future metro-access architecture that comprises Optical Burst Switching networks that feed Ethernet Passive Optical Networks (PON) or upcoming Wavelength-Division Multiplexing PON, which in turn feed IEEE 802.16 and IEEE 802.11 nodes. Nodes in the wireless realm may communicate in a multihop fashion, forming mesh networks. To maintain cost and resource efficiency, we propose the introduction of Quality of Service (QoS) proxies at the border between different link technologies. These entities handle QoS requirements and aid to the support of mobility. The architecture requires no modification of the Medium Access Control mechanisms of the different technologies. Index Terms-Optical fiber communication, mobile communication, metropolitan area networks.
We propose a new protocol, named DS-SWAN (Differentiated Services-Stateless Wireless Ad Hoc Netwo... more We propose a new protocol, named DS-SWAN (Differentiated Services-Stateless Wireless Ad Hoc Networks), to support end-to-end Quality of Service (QoS) in ad hoc networks connected to a fixed DiffServ domain. When congestion is excessive for the correct functioning of real-time applications, DS-SWAN determines the source of the problem, warns the nodes in the ad hoc network if it is the case and the nodes react by slowing down best-effort traffic. Furthermore, we present an associated routing protocol for the ad hoc network in this context, named SD-AODV (Service Differentiation-Ad Hoc On-Demand Distance Vector), where new route requests are suppressed at certain nodes to maintain the desired QoS requirements for real-time flows. A simulation study is presented for the case when traffic is sent from the ad hoc network towards the fixed network as well as in the opposite direction. The scalability of DS-SWAN with respect to the network size, number of real-time traffic sources, node mobility and best-effort traffic load is analyzed. Simulation results indicate that DS-SWAN and SD-AODV significantly improve end-to-end delays and jitter for real-time flows without starvation of background traffic.
Proceedings of the 7th ACM international symposium on Modeling, analysis and simulation of wireless and mobile systems - MSWiM '04, 2004
... MC Domingo Telematics Eng. ... 1. INTRODUCTION Several authors have presented proposals to su... more ... MC Domingo Telematics Eng. ... 1. INTRODUCTION Several authors have presented proposals to support QoS (Quality of Service) in isolated ad hoc networks, including QoS oriented MAC protocols [1], QoS aware routing protocols [2] and resource reservation protocols such as ...
This paper analyzes the provision of end-to-end Quality of Service between nodes in a mobile ad h... more This paper analyzes the provision of end-to-end Quality of Service between nodes in a mobile ad hoc network and a fixed IP network that supports Differentiated Services. The ad hoc network incorporates the Stateless Wireless Ad Hoc Networks (SWAN) model to perform admission control for real-time traffic flows. We propose a new protocol, named DS-SWAN (Differentiated Services-SWAN), where end-to-end delays and loss rates of real-time traffic are monitored continuously at the destination nodes in the fixed network and at the edge routers respectively. In this way, nodes in the ad hoc network are warned when congestion is excessive for the correct functioning of a real-time application (specifically, Variable Bit Rate Voice-over-IP), so that the nodes restrain best-effort traffic in order to favour real-time flows. The results indicate that DS-SWAN significantly improves end-to-end delays without starvation of background traffic, adapting itself to changing traffic and network conditions in a relatively small ad hoc network. Besides, we compare different notification procedures in DS-SWAN aimed to improve scalability.
... We have evaluated and compared the performance of a Page 9. 82 MC Domingo and D. Remondo Fig.... more ... We have evaluated and compared the performance of a Page 9. 82 MC Domingo and D. Remondo Fig. ... However, each node calculates the average MAC delays during the simulation. Fig. 5 represents the average end-to-end delays for VoIP. ...
Proceedings - Advanced Industrial Conference on Telecommunications/Service Assurance with Partial and Intermittent Resources Conference/E-Learning on Telecommunications Workshop AICT/SAPIR/ELETE 2005, 2005
We propose a new protocol, named DS-SWAN (Differentiated Services-Stateless Wireless Ad Hoc Netwo... more We propose a new protocol, named DS-SWAN (Differentiated Services-Stateless Wireless Ad Hoc Networks), to support end-to-end QoS (Quality of Service) in ad hoc networks connected to fixed DiffServ domains. DS-SWAN warns nodes in the ad hoc network when congestion is excessive for the correct functioning of real-time applications. These nodes react by slowing down best-effort traffic. Furthermore, we present a routing protocol for the ad hoc network, named SD-AODV (Service Differentiation-Ad Hoc On-demand Distance Vector), where new route requests are suppressed at certain nodes to maintain the desired QoS requirements for real-time flows. Simulation results indicate that DS-SWAN and SD-AODV significantly improve end-to-end delays for real-time flows without starvation of background traffic. In this work we also present several versions of the SD-AODV routing protocol and study their behaviour.
International Journal of Wireless and Mobile Computing, 2010
... Garg, S., Kappes, M. and Trivedi, KS (2002a) Supporting VoIP Traffic in IEEE 802.11 WLAN with... more ... Garg, S., Kappes, M. and Trivedi, KS (2002a) Supporting VoIP Traffic in IEEE 802.11 WLAN with Enhanced Medium Access Control (MAC) for Quality of Service, www.research.avayalabs.com/ techreport/ALR-2002-025-paper.pdf Domingo, MC and Remondo, D. (2004) 'Quality ...
... we modified the DSR protocol and created a new version that is named SEADSR (Simple Energy Aw... more ... we modified the DSR protocol and created a new version that is named SEADSR (Simple Energy Aware DSR). In this work we have run simulations of DSR and SEADSR using IEEE 802.11b as link layer. ... The second section explains the basic functioning of the DSR protocol. ...
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Papers by David Remondo