Cathryn J Peoples - Academia.edu (original) (raw)
Papers by Cathryn J Peoples
Page 1. 1 Green Networks and Communications C. Peoples, G. Parr, S. McClean, and P. Morrow Page 2... more Page 1. 1 Green Networks and Communications C. Peoples, G. Parr, S. McClean, and P. Morrow Page 2. 2 KEY POINTS • Presents the drivers and benefits of energy efficient computer networks and communications. • Describes ...
Context-awareness is inherent in anticipated interplanetary missions. Swarm technologies by D&... more Context-awareness is inherent in anticipated interplanetary missions. Swarm technologies by D'Arrigo, P, Santandrea, S. (2005) use context-awareness in short-haul networks between components, and long-distance networks allow communication with Earth. However, the propagation delays limit real-time communications, deep space being an environment in which the speed of light becomes a restriction. Therefore, the development of a protocol stack which is adaptive
Carbon emissions are receiving increased attention and scrutiny in all walks of life and the ICT ... more Carbon emissions are receiving increased attention and scrutiny in all walks of life and the ICT sector is no exception. With the increase in on-demand applications and services together with on-demand compute/storage facilities in server farms or data centres there are self-evident increases in the power requirements to maintain such systems. Proponents of the impact of increased carbon emissions when powering electrical systems in general however, regularly impress negative side-effects such as influence on climate change. Action is subsequently being encouraged to halt further environmental damage. The problem is explored in this paper from the point of view of carbon emissions from data centre operations and the development of energy-aware management and energy-efficient networking solutions. Data centre energy consumption costs drive the evaluation process within a Data Centre Energy-Efficient Context-Aware Broker (DCe-CAB) algorithm designed as an original solution to this significant carbon-contributing network scenario. In this paper, performance requirements and objectives of the DCe-CAB are defined, along with case study demonstration of the way in which it optimises selection and operation of data centres using context-awareness.
Energyefficient dynamic management uses energy-aware findings to achieve energy-efficiency 1 2 Ca... more Energyefficient dynamic management uses energy-aware findings to achieve energy-efficiency 1 2 Carbon cost C1 (default network cost) Carbon cost C2 where C2<C1 is the management objective After dynamic management (during which energyawareness drives energy-efficiency), C2 ∝ Pr(el, Q, B, ER, R)
2012 Second Symposium on Network Cloud Computing and Applications, 2012
ABSTRACT Clouds and data centres are significant consumers of power. There are however, opportuni... more ABSTRACT Clouds and data centres are significant consumers of power. There are however, opportunities for optimising carbon cost here as resource redundancy is provisioned extensively. Data centre resources, and subsequently clouds which support them, are traditionally organised into tiers; switch-off activity when managing redundant resources therefore occurs in an approach which exploits cost advantages associated with closing down entire network portions. We suggest however, an alternative approach to optimise cloud operation while maintaining application QoS: Simulation experiments identify that network operation can be optimised by selecting servers which process traffic at a rate that more closely matches the packet arrival rate, and resources which provision excessive capacity additional to that required may be powered off for improved efficiency. This recognises that there is a point in server speed at which performance is optimised, and operation which is greater than or less than this rate will not achieve optimisation. A series of policies have been defined in this work for integration into cloud management procedures; performance results from their implementation and evaluation in simulation show improved efficiency by selecting servers based on these relationships.
IEEE Aerospace and Electronic Systems Magazine, 2000
ABSTRACT Maintaining connectivity in deep-space communications is of critical importance to key m... more ABSTRACT Maintaining connectivity in deep-space communications is of critical importance to key missions and the abWty to adapt node behavior "on-the-Jly" can have dynamic benefits. Autonomic operation minimizes failur e risk by performing local configurations using collected context data and on-board poUcles, improving response time to events, and reducing remote mission management expense. Herein, we evaluate cost-benefit impacts when a context-aware brokerlng algorithm developed to achieve autonomy Is appUed to Interplanetary communications systems.
International Workshop on Space and Satellite Communications (IWSSC '07), Sep 2007
We examine how the design of the Transmission Control Protocol (TCP) implicitly presumes a limite... more We examine how the design of the Transmission Control Protocol (TCP) implicitly presumes a limited range of path delays and distances between communicating endpoints
Mobile networks currently play a key role in the evolution of the Internet due to exponential inc... more Mobile networks currently play a key role in the evolution of the Internet due to exponential increase in demand for Internet-enabled mobile devices and applications. This has led to various demands to re-think basic designs of the current Internet architecture, investigating new and innovative ways in which key functionalities such as end-to-end connectivity, mobility, security, cloud services and future requirements can be added to its foundational core design. In this paper, we investigate, propose and design a functional element, known as the mobile cloud proxy, that enables the seamless integration and extension of core cloud services on the public Internet into mobile networks. The mobile cloud proxy function addresses current limitations in the deployment of cloud services in mobile networks tackling limitations such as dynamic resource allocation, transport protocols, application caching and security. This is achieved by leveraging advances in software-defined radios (SDRs) ...
Simulation Modelling Practice and Theory
Network management is increasingly being customised for green objectives due to roll out of missi... more Network management is increasingly being customised for green objectives due to roll out of mission-critical applications across the internet of things and execution, in a number of cases, on battery-constrained devices. In addition, the volume of operations across the internet of things is attracting climate change concerns. While operational efficiency of wireless devices and in data centres (which support operation of the internet of things) should not be achieved at the expense of Quality of Service, optimisation opportunities should be exploited and inefficient resource use minimised. Green networking approaches however, are not yet standardised, and there is scope for novel middleware architectures. In this paper, we explore operational efficiency from the perspective of activities in data centres which support the internet of things. This includes evaluation of the effectiveness of mechanisms integrated into the e-CAB framework, an algorithm proposed by the authors to manage ...
Data centre energy costs are reduced when virtualisation is used as opposed to physical resource ... more Data centre energy costs are reduced when virtualisation is used as opposed to physical resource deployment to a volume sufficient to accommodate all application requests. Nonetheless, regardless of the resource provisioning approach, opportunities remain in the way in which they are made available and workload is scheduled. Cost incurred at a server is a function of its hardware characteristics. The objective of our approach is therefore to pack workload into servers, selected as a function of their cost to operate, to achieve (or as close to) the maximum recommended utilisation in a cost-efficient manner, avoiding instances where devices are under-utilised and management cost is incurred inefficiently. This is based on queuing theory principles and the relationship between packet arrival rate, service rate and response time, and recognises a similar exponential relationship between power cost and server utilisation to drive its intelligent selection for improved efficiency. There ...
Mobile networks have gone through various stages of evolution with each stage aimed at addressing... more Mobile networks have gone through various stages of evolution with each stage aimed at addressing a wide range of challenges and limitations. During the early evolutions of mobile networks - 2G, 2.5G, 3G -, the key challenge was to investigate efficient and cost effective ways of delivering higher data speeds. This led to the proposals and development of 4G LTE networks based on a flat all-IP architecture with Internet based protocols. However, recent trends indicates that the Internet-like architecture in mobile networks has further enabled Internet based cloud service providers to provide Over-The-Top (OTT) applications to mobile devices bypassing and competing with the mobile operator on services such as voice, video, messaging and gaming. This is a key motivation for cloud service providers and mobile operators to explore various opportunities in which they can both leverage on their existing infrastructures in order to efficiently deploy cloud services in mobile environments. I...
Standardised and interoperable management solutions are an objective for the next generation of c... more Standardised and interoperable management solutions are an objective for the next generation of cloud to autonomically provision and configure resources in a manner generically applicable across platforms and applications. Cloud interoperability is desirable in spite of platforms having variable management requirements and applications having various resource demands. In this paper, the resource footprint of an application, Wisekar, developed at the Indian Institute of Technology Delhi is explored, alongside consideration of its scalability with increasing volumes of requests. The limiting network resource in this deployment is bandwidth, which restricts the extent to which memory and CPU resources can be consumed, regardless of the number of application requests sent to the server. Definition of resource consumption relationships between attributes while servicing application requests leads to recommendations on server and network loading which optimises the overall utilisation acr...
Roll-out of future cloud systems will be influenced by regulations from the standardisation bodie... more Roll-out of future cloud systems will be influenced by regulations from the standardisation bodies, if made available across the community. Trends in cloud deployment, operation and management to date have not been guided by any regulatory standards, and resources have been deployed in an ad hoc manner as demanded according to the business objectives of service providers. This is the least costly and most quickly revenue-returning business model. It is not however, the most cost-effective approach on a long-term basis: As a consequence of this roll-out model to date, the interoperability of resources deployed across clouds managed by different operators is restricted through inability to allocate workload to them in a regulated and controllable manner. The absence of standardised approaches to cloud management is therefore beginning to be accommodated such that the cost and performance advantages of interoperable operation may be exploited. In this paper, we review the state-of-the-...
Second International Conference on Internet Monitoring and Protection (ICIMP 2007), 2007
A Delay-Tolerant Network (DTN) is a necessity for communication nodes that may need to wait for l... more A Delay-Tolerant Network (DTN) is a necessity for communication nodes that may need to wait for long periods to form networks. The IETF Delay Tolerant Network Research Group is developing protocols to enable such networks for a broad variety of Earth and interplanetary applications. The Arctic would benefit from a predictive velocity-enabled version of DTN that would facilitate communications between sparse, ephemeral, often mobile and extremely power-limited nodes. We propose to augment DTN with power-aware, buffer-aware location-and time-based predictive routing for ad-hoc meshes to create networks that are inherently location and time (velocity) aware at the network level to support climate research, emergency services and rural education in the Arctic. On Earth, the primary source of location and universal time information for networks is the Global Positioning System (GPS). We refer to this Arctic velocity-enabled Delay-Tolerant Network protocol as "GPSDTN" accordingly. This paper describes our requirements analysis and general implementation strategy for GPSDTN to support Arctic research and sustainability efforts.
2007 International Workshop on Satellite and Space Communications, 2007
This paper presents an approach to improve transmission success in delay-tolerant networks. The C... more This paper presents an approach to improve transmission success in delay-tolerant networks. The Context-Aware Broker (CAB) grants networking autonomy when communicating in challenging environments, which suffer from conditions which are variable and exceed the limits for which terrestrial protocols were designed. Such environments currently require human intervention and the manual configuration of each communication -a seemingly simple decision of when to transmit becomes an issue in deep space due to planet movement. However, manual configuration is becoming unrealistic, given the scale on which communications occur. CAB automates the process by making intelligent decisions before transmission begins, and reconfigures as it progresses. It recognises the dynamic environments through which a transmission may pass and matches protocol capabilities with environmental constraints.
2010 International Conference on Network and Service Management, 2010
This paper presents a framework for context-driven policy-based QoS control and end-to-end resour... more This paper presents a framework for context-driven policy-based QoS control and end-to-end resource management in converged next generation networks. The Converged Networks QoS Framework (CNQF) is being developed within the IU-ATC project, and comprises distributed functional entities whose instances co-ordinate the converged network infrastructure to facilitate scalable and efficient end-to-end QoS management. The CNQF design leverages aspects of TISPAN, IETF
2007 International Workshop on Satellite and Space Communications, 2007
We examine how the design of the Transmission Control Protocol (TCP) implicitly presumes a limite... more We examine how the design of the Transmission Control Protocol (TCP) implicitly presumes a limited range of path delays and distances between communicating endpoints. We show that TCP is less suited to larger delays due to the interaction of various timers present in TCP implementations that limit performance and, eventually, the ability to communicate at all as distances increase. The resulting performance and protocol radius metrics that we establish by simulation indicate how the TCP protocol performs with increasing distance radius between two communicating nodes, and show the boundaries where the protocol undergoes visible performance changes. This allows us to assess the suitability of TCP for long-delay communication, including for deep-space links.
The world of telecommunications continues to provide radical technologies. Offering the benefits ... more The world of telecommunications continues to provide radical technologies. Offering the benefits of a superior television experience at reduced long-term costs, IPTV is the newest offering. Deployments, however, are slow to be rolled out; the hardware and software support necessary is not uniformly available. This paper examines the challenges in providing IPTV services and the limitations in developments to overcome these challenges. Subsequently, a proposal is made which attempts to help solve the challenge of fulfilling real-time multimedia transmissions through provisioning for differentiated services. Initial implementations in Opnet are documented, and the paper concludes with an outline of future work.
Proceedings of the 4th International ICST Conference on Simulation Tools and Techniques, 2011
Energy-awareness and resilience are becoming increasingly important in network research. So far, ... more Energy-awareness and resilience are becoming increasingly important in network research. So far, they have been mainly considered independently from each other, but it has become clear that there are important interdependencies. Resilience should be achieved in a manner which is energy-efficient, and energy-efficiency objectives should respect the networks' need to be prepared to observe and react against disruptive activity. Meeting these complementary and sometimes conflicting research objectives demands novel strategies to support energy-efficient resilience management. However, the effective evaluation of cross-cutting energy and resilience management aspects is difficult to achieve using the tool support currently available. In this paper, we explore a range of network simulation environments and assess their ability to meet our energy and resilience modelling objectives as a function of their technical capabilities. Furthermore, ways in which these tools can be extended based on previous related implementations are also considered.
This paper presents a framework for context-driven policy-based QoS control and end-to-end resour... more This paper presents a framework for context-driven policy-based QoS control and end-to-end resource management in converged next generation networks. The Converged Networks QoS Framework (CNQF) is being developed within the IU-ATC project, and comprises distributed functional entities whose instances co-ordinate the converged network infrastructure to facilitate scalable and efficient end-to-end QoS management. The CNQF design leverages aspects of TISPAN, IETF and 3GPP policy-based management architectures whilst also introducing important innovative extensions to support context-aware QoS control in converged networks. The framework architecture is presented and its functionalities and operation in specific application scenarios are described.
Page 1. 1 Green Networks and Communications C. Peoples, G. Parr, S. McClean, and P. Morrow Page 2... more Page 1. 1 Green Networks and Communications C. Peoples, G. Parr, S. McClean, and P. Morrow Page 2. 2 KEY POINTS • Presents the drivers and benefits of energy efficient computer networks and communications. • Describes ...
Context-awareness is inherent in anticipated interplanetary missions. Swarm technologies by D&... more Context-awareness is inherent in anticipated interplanetary missions. Swarm technologies by D&amp;amp;amp;#x27;Arrigo, P, Santandrea, S. (2005) use context-awareness in short-haul networks between components, and long-distance networks allow communication with Earth. However, the propagation delays limit real-time communications, deep space being an environment in which the speed of light becomes a restriction. Therefore, the development of a protocol stack which is adaptive
Carbon emissions are receiving increased attention and scrutiny in all walks of life and the ICT ... more Carbon emissions are receiving increased attention and scrutiny in all walks of life and the ICT sector is no exception. With the increase in on-demand applications and services together with on-demand compute/storage facilities in server farms or data centres there are self-evident increases in the power requirements to maintain such systems. Proponents of the impact of increased carbon emissions when powering electrical systems in general however, regularly impress negative side-effects such as influence on climate change. Action is subsequently being encouraged to halt further environmental damage. The problem is explored in this paper from the point of view of carbon emissions from data centre operations and the development of energy-aware management and energy-efficient networking solutions. Data centre energy consumption costs drive the evaluation process within a Data Centre Energy-Efficient Context-Aware Broker (DCe-CAB) algorithm designed as an original solution to this significant carbon-contributing network scenario. In this paper, performance requirements and objectives of the DCe-CAB are defined, along with case study demonstration of the way in which it optimises selection and operation of data centres using context-awareness.
Energyefficient dynamic management uses energy-aware findings to achieve energy-efficiency 1 2 Ca... more Energyefficient dynamic management uses energy-aware findings to achieve energy-efficiency 1 2 Carbon cost C1 (default network cost) Carbon cost C2 where C2<C1 is the management objective After dynamic management (during which energyawareness drives energy-efficiency), C2 ∝ Pr(el, Q, B, ER, R)
2012 Second Symposium on Network Cloud Computing and Applications, 2012
ABSTRACT Clouds and data centres are significant consumers of power. There are however, opportuni... more ABSTRACT Clouds and data centres are significant consumers of power. There are however, opportunities for optimising carbon cost here as resource redundancy is provisioned extensively. Data centre resources, and subsequently clouds which support them, are traditionally organised into tiers; switch-off activity when managing redundant resources therefore occurs in an approach which exploits cost advantages associated with closing down entire network portions. We suggest however, an alternative approach to optimise cloud operation while maintaining application QoS: Simulation experiments identify that network operation can be optimised by selecting servers which process traffic at a rate that more closely matches the packet arrival rate, and resources which provision excessive capacity additional to that required may be powered off for improved efficiency. This recognises that there is a point in server speed at which performance is optimised, and operation which is greater than or less than this rate will not achieve optimisation. A series of policies have been defined in this work for integration into cloud management procedures; performance results from their implementation and evaluation in simulation show improved efficiency by selecting servers based on these relationships.
IEEE Aerospace and Electronic Systems Magazine, 2000
ABSTRACT Maintaining connectivity in deep-space communications is of critical importance to key m... more ABSTRACT Maintaining connectivity in deep-space communications is of critical importance to key missions and the abWty to adapt node behavior "on-the-Jly" can have dynamic benefits. Autonomic operation minimizes failur e risk by performing local configurations using collected context data and on-board poUcles, improving response time to events, and reducing remote mission management expense. Herein, we evaluate cost-benefit impacts when a context-aware brokerlng algorithm developed to achieve autonomy Is appUed to Interplanetary communications systems.
International Workshop on Space and Satellite Communications (IWSSC '07), Sep 2007
We examine how the design of the Transmission Control Protocol (TCP) implicitly presumes a limite... more We examine how the design of the Transmission Control Protocol (TCP) implicitly presumes a limited range of path delays and distances between communicating endpoints
Mobile networks currently play a key role in the evolution of the Internet due to exponential inc... more Mobile networks currently play a key role in the evolution of the Internet due to exponential increase in demand for Internet-enabled mobile devices and applications. This has led to various demands to re-think basic designs of the current Internet architecture, investigating new and innovative ways in which key functionalities such as end-to-end connectivity, mobility, security, cloud services and future requirements can be added to its foundational core design. In this paper, we investigate, propose and design a functional element, known as the mobile cloud proxy, that enables the seamless integration and extension of core cloud services on the public Internet into mobile networks. The mobile cloud proxy function addresses current limitations in the deployment of cloud services in mobile networks tackling limitations such as dynamic resource allocation, transport protocols, application caching and security. This is achieved by leveraging advances in software-defined radios (SDRs) ...
Simulation Modelling Practice and Theory
Network management is increasingly being customised for green objectives due to roll out of missi... more Network management is increasingly being customised for green objectives due to roll out of mission-critical applications across the internet of things and execution, in a number of cases, on battery-constrained devices. In addition, the volume of operations across the internet of things is attracting climate change concerns. While operational efficiency of wireless devices and in data centres (which support operation of the internet of things) should not be achieved at the expense of Quality of Service, optimisation opportunities should be exploited and inefficient resource use minimised. Green networking approaches however, are not yet standardised, and there is scope for novel middleware architectures. In this paper, we explore operational efficiency from the perspective of activities in data centres which support the internet of things. This includes evaluation of the effectiveness of mechanisms integrated into the e-CAB framework, an algorithm proposed by the authors to manage ...
Data centre energy costs are reduced when virtualisation is used as opposed to physical resource ... more Data centre energy costs are reduced when virtualisation is used as opposed to physical resource deployment to a volume sufficient to accommodate all application requests. Nonetheless, regardless of the resource provisioning approach, opportunities remain in the way in which they are made available and workload is scheduled. Cost incurred at a server is a function of its hardware characteristics. The objective of our approach is therefore to pack workload into servers, selected as a function of their cost to operate, to achieve (or as close to) the maximum recommended utilisation in a cost-efficient manner, avoiding instances where devices are under-utilised and management cost is incurred inefficiently. This is based on queuing theory principles and the relationship between packet arrival rate, service rate and response time, and recognises a similar exponential relationship between power cost and server utilisation to drive its intelligent selection for improved efficiency. There ...
Mobile networks have gone through various stages of evolution with each stage aimed at addressing... more Mobile networks have gone through various stages of evolution with each stage aimed at addressing a wide range of challenges and limitations. During the early evolutions of mobile networks - 2G, 2.5G, 3G -, the key challenge was to investigate efficient and cost effective ways of delivering higher data speeds. This led to the proposals and development of 4G LTE networks based on a flat all-IP architecture with Internet based protocols. However, recent trends indicates that the Internet-like architecture in mobile networks has further enabled Internet based cloud service providers to provide Over-The-Top (OTT) applications to mobile devices bypassing and competing with the mobile operator on services such as voice, video, messaging and gaming. This is a key motivation for cloud service providers and mobile operators to explore various opportunities in which they can both leverage on their existing infrastructures in order to efficiently deploy cloud services in mobile environments. I...
Standardised and interoperable management solutions are an objective for the next generation of c... more Standardised and interoperable management solutions are an objective for the next generation of cloud to autonomically provision and configure resources in a manner generically applicable across platforms and applications. Cloud interoperability is desirable in spite of platforms having variable management requirements and applications having various resource demands. In this paper, the resource footprint of an application, Wisekar, developed at the Indian Institute of Technology Delhi is explored, alongside consideration of its scalability with increasing volumes of requests. The limiting network resource in this deployment is bandwidth, which restricts the extent to which memory and CPU resources can be consumed, regardless of the number of application requests sent to the server. Definition of resource consumption relationships between attributes while servicing application requests leads to recommendations on server and network loading which optimises the overall utilisation acr...
Roll-out of future cloud systems will be influenced by regulations from the standardisation bodie... more Roll-out of future cloud systems will be influenced by regulations from the standardisation bodies, if made available across the community. Trends in cloud deployment, operation and management to date have not been guided by any regulatory standards, and resources have been deployed in an ad hoc manner as demanded according to the business objectives of service providers. This is the least costly and most quickly revenue-returning business model. It is not however, the most cost-effective approach on a long-term basis: As a consequence of this roll-out model to date, the interoperability of resources deployed across clouds managed by different operators is restricted through inability to allocate workload to them in a regulated and controllable manner. The absence of standardised approaches to cloud management is therefore beginning to be accommodated such that the cost and performance advantages of interoperable operation may be exploited. In this paper, we review the state-of-the-...
Second International Conference on Internet Monitoring and Protection (ICIMP 2007), 2007
A Delay-Tolerant Network (DTN) is a necessity for communication nodes that may need to wait for l... more A Delay-Tolerant Network (DTN) is a necessity for communication nodes that may need to wait for long periods to form networks. The IETF Delay Tolerant Network Research Group is developing protocols to enable such networks for a broad variety of Earth and interplanetary applications. The Arctic would benefit from a predictive velocity-enabled version of DTN that would facilitate communications between sparse, ephemeral, often mobile and extremely power-limited nodes. We propose to augment DTN with power-aware, buffer-aware location-and time-based predictive routing for ad-hoc meshes to create networks that are inherently location and time (velocity) aware at the network level to support climate research, emergency services and rural education in the Arctic. On Earth, the primary source of location and universal time information for networks is the Global Positioning System (GPS). We refer to this Arctic velocity-enabled Delay-Tolerant Network protocol as "GPSDTN" accordingly. This paper describes our requirements analysis and general implementation strategy for GPSDTN to support Arctic research and sustainability efforts.
2007 International Workshop on Satellite and Space Communications, 2007
This paper presents an approach to improve transmission success in delay-tolerant networks. The C... more This paper presents an approach to improve transmission success in delay-tolerant networks. The Context-Aware Broker (CAB) grants networking autonomy when communicating in challenging environments, which suffer from conditions which are variable and exceed the limits for which terrestrial protocols were designed. Such environments currently require human intervention and the manual configuration of each communication -a seemingly simple decision of when to transmit becomes an issue in deep space due to planet movement. However, manual configuration is becoming unrealistic, given the scale on which communications occur. CAB automates the process by making intelligent decisions before transmission begins, and reconfigures as it progresses. It recognises the dynamic environments through which a transmission may pass and matches protocol capabilities with environmental constraints.
2010 International Conference on Network and Service Management, 2010
This paper presents a framework for context-driven policy-based QoS control and end-to-end resour... more This paper presents a framework for context-driven policy-based QoS control and end-to-end resource management in converged next generation networks. The Converged Networks QoS Framework (CNQF) is being developed within the IU-ATC project, and comprises distributed functional entities whose instances co-ordinate the converged network infrastructure to facilitate scalable and efficient end-to-end QoS management. The CNQF design leverages aspects of TISPAN, IETF
2007 International Workshop on Satellite and Space Communications, 2007
We examine how the design of the Transmission Control Protocol (TCP) implicitly presumes a limite... more We examine how the design of the Transmission Control Protocol (TCP) implicitly presumes a limited range of path delays and distances between communicating endpoints. We show that TCP is less suited to larger delays due to the interaction of various timers present in TCP implementations that limit performance and, eventually, the ability to communicate at all as distances increase. The resulting performance and protocol radius metrics that we establish by simulation indicate how the TCP protocol performs with increasing distance radius between two communicating nodes, and show the boundaries where the protocol undergoes visible performance changes. This allows us to assess the suitability of TCP for long-delay communication, including for deep-space links.
The world of telecommunications continues to provide radical technologies. Offering the benefits ... more The world of telecommunications continues to provide radical technologies. Offering the benefits of a superior television experience at reduced long-term costs, IPTV is the newest offering. Deployments, however, are slow to be rolled out; the hardware and software support necessary is not uniformly available. This paper examines the challenges in providing IPTV services and the limitations in developments to overcome these challenges. Subsequently, a proposal is made which attempts to help solve the challenge of fulfilling real-time multimedia transmissions through provisioning for differentiated services. Initial implementations in Opnet are documented, and the paper concludes with an outline of future work.
Proceedings of the 4th International ICST Conference on Simulation Tools and Techniques, 2011
Energy-awareness and resilience are becoming increasingly important in network research. So far, ... more Energy-awareness and resilience are becoming increasingly important in network research. So far, they have been mainly considered independently from each other, but it has become clear that there are important interdependencies. Resilience should be achieved in a manner which is energy-efficient, and energy-efficiency objectives should respect the networks' need to be prepared to observe and react against disruptive activity. Meeting these complementary and sometimes conflicting research objectives demands novel strategies to support energy-efficient resilience management. However, the effective evaluation of cross-cutting energy and resilience management aspects is difficult to achieve using the tool support currently available. In this paper, we explore a range of network simulation environments and assess their ability to meet our energy and resilience modelling objectives as a function of their technical capabilities. Furthermore, ways in which these tools can be extended based on previous related implementations are also considered.
This paper presents a framework for context-driven policy-based QoS control and end-to-end resour... more This paper presents a framework for context-driven policy-based QoS control and end-to-end resource management in converged next generation networks. The Converged Networks QoS Framework (CNQF) is being developed within the IU-ATC project, and comprises distributed functional entities whose instances co-ordinate the converged network infrastructure to facilitate scalable and efficient end-to-end QoS management. The CNQF design leverages aspects of TISPAN, IETF and 3GPP policy-based management architectures whilst also introducing important innovative extensions to support context-aware QoS control in converged networks. The framework architecture is presented and its functionalities and operation in specific application scenarios are described.