825,859 research outputs found
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A management architecture for active networks
In this paper we present an architecture for network and applications management, which is based on the Active Networks paradigm and shows the advantages of network programmability. The stimulus to develop this architecture arises from an actual need to manage a cluster of active nodes, where it is often required to redeploy network assets and modify nodes connectivity. In our architecture, a remote front-end of the managing entity allows the operator to design new network topologies, to check the status of the nodes and to configure them. Moreover, the proposed framework allows to explore an active network, to monitor the active applications, to query each node and to install programmable traps. In order to take advantage of the Active Networks technology, we introduce active SNMP-like MIBs and agents, which are dynamic and programmable. The programmable management agents make tracing distributed applications a feasible task. We propose a general framework that can inter-operate with any active execution environment. In this framework, both the manager and the monitor front-ends communicate with an active node (the Active Network Access Point) through the XML language. A gateway service performs the translation of the queries from XML to an active packet language and injects the code in the network. We demonstrate the implementation of an active network gateway for PLAN (Packet Language for Active Networks) in a forty active nodes testbed. Finally, we discuss an application of the active management architecture to detect the causes of network failures by tracing network events in time
Recommended from our members
A management architecture for active networks
In this paper we present an architecture for network and applications management, which is based on the Active Networks paradigm and shows the advantages of network programmability. The stimulus to develop this architecture arises from an actual need to manage a cluster of active nodes, where it is often required to redeploy network assets and modify nodes connectivity. In our architecture, a remote front-end of the managing entity allows the operator to design new network topologies, to check the status of the nodes and to configure them. Moreover, the proposed framework allows to explore an active network, to monitor the active applications, to query each node and to install programmable traps. In order to take advantage of the Active Networks technology, we introduce active SNMP-like MIBs and agents, which are dynamic and programmable. The programmable management agents make tracing distributed applications a feasible task. We propose a general framework that can inter-operate with any active execution environment. In this framework, both the manager and the monitor front-ends communicate with an active node (the Active Network Access Point) through the XML language. A gateway service performs the translation of the queries from XML to an active packet language and injects the code in the network. We demonstrate the implementation of an active network gateway for PLAN (Packet Language for Active Networks) in a forty active nodes testbed. Finally, we discuss an application of the active management architecture to detect the causes of network failures by tracing network events in time
Choice of State Estimation Solution Process for Medium Voltage Distribution Systems
As distribution networks are turning into active systems, enhanced observability and continuous monitoring becomes essential for effective management and control. The state estimation (SE) tool is therefore now considered as the core component in future distribution management systems. The development of a novel distribution system SE tool is required to accommodate small to very large networks, operable with limited real time measurements and able to execute the computation of large volumes of data in a limited time frame. In this context, the paper investigates the computation time and voltage estimation qualities of three different SE optimization solution methods in order to evaluate their effectiveness as potential distribution SE candidate solutions
Formal Scheduling Constraints for Time-Sensitive Networks
In recent years, the IEEE 802.1 Time Sensitive Networking (TSN) task group
has been active standardizing time-sensitive capabilities for Ethernet networks
ranging from distributed clock synchronization and time-based ingress policing
to frame preemption, redundancy management, and scheduled traffic enhancements.
In particular the scheduled traffic enhancements defined in IEEE 802.1Qbv
together with the clock synchronization protocol open up the possibility to
schedule communication in distributed networks providing real-time guarantees.
In this paper we formalize the necessary constraints for creating
window-based IEEE~802.1Qbv Gate Control List schedules for Time-sensitive
Networks (TSN). The resulting schedules allow a greater flexibility in terms of
timing properties while still guaranteeing deterministic communication with
bounded jitter and end-to-end latency
Meeting Real-Time Constraint of Spectrum Management in TV Black-Space Access
The TV set feedback feature standardized in the next generation TV system,
ATSC 3.0, would enable opportunistic access of active TV channels in future
Cognitive Radio Networks. This new dynamic spectrum access approach is named as
black-space access, as it is complementary of current TV white space, which
stands for inactive TV channels. TV black-space access can significantly
increase the available spectrum of Cognitive Radio Networks in populated urban
markets, where spectrum shortage is most severe while TV whitespace is very
limited. However, to enable TV black-space access, secondary user has to
evacuate a TV channel in a timely manner when TV user comes in. Such strict
real-time constraint is an unique challenge of spectrum management
infrastructure of Cognitive Radio Networks. In this paper, the real-time
performance of spectrum management with regard to the degree of centralization
of infrastructure is modeled and tested. Based on collected empirical network
latency and database response time, we analyze the average evacuation time
under four structures of spectrum management infrastructure: fully
distribution, city-wide centralization, national-wide centralization, and
semi-national centralization. The results show that national wide
centralization may not meet the real-time requirement, while semi-national
centralization that use multiple co-located independent spectrum manager can
achieve real-time performance while keep most of the operational advantage of
fully centralized structure.Comment: 9 pages, 7 figures, Technical Repor
Optimisation of routing protocols for Wireless Mesh Networks (WMNs) to achieve higher quality of service for real time applications
The existing routing protocols for WMNs (Wireless Mesh Networks) are extensions of protocols originally designed for Mobile Ad-hoc Networks (MANETs) and perform sub-optimally for the mesh connectivity of WMNs which degrades their performance in terms of increased latency in packet delivery, packet drops and decreased network throughput. The proposed research, currently at its inception, would investigate into capacity and limitations of current WMN routing protocols with respect to wireless technologies, platforms and relevant standards in context of routing requirements of identified real-time applications, namely, the disaster management and tele-health applications. The research would optimise the existing routing protocols for WMNs for the proposed applications to achieve higher quality of service, reliability and security of data access to meet their specialist requirements. Wireless Mesh Networks (WMNs) are increasingly being incorporated in disaster management solutions for access to information of disaster situation to improve effectiveness of rescue services. Currently, the routing requirements of disaster solution using WMN has been researched in context of active research project, “iSurvival- Mobile Mesh Networks for Disaster Management” , which utilises specialist applications on smart phones of end-users in the disaster area to establish WMNs using available heterogeneous wireless technologies from 3G, Wi-Fi, Bluetooth and others. These WMNs provide resilient and reconfigurable digital infrastructures, with users’ smart phones acting as routers in the connected mesh networks to facilitate routing and forwarding of information in the disaster are
Design and performance evaluation of a state-space based AQM
Recent research has shown the link between congestion control in
communication networks and feedback control system. In this paper, the design
of an active queue management (AQM) which can be viewed as a controller, is
considered. Based on a state space representation of a linearized fluid flow
model of TCP, the AQM design is converted to a state feedback synthesis problem
for time delay systems. Finally, an example extracted from the literature and
simulations via a network simulator NS (under cross traffic conditions) support
our study
Using dynamic optimal power flow to inform the design and operation of active network management schemes
Active Network Management (ANM) schemes are providing the communications and control infrastructure to allow the integration of energy storage and flexible demand in distribution networks. These technologies can be characterised as intertemporal in that their operation at different points in time is linked. This paper provides a discussion of the issues created when optimising an ANM scheme containing intertemporal energy technologies. A technique called Dynamic Optimal Power Flow is discussed and a case study is presented. The requirement to use forecasts of renewable energy resources such as wind power is discussed together with the issues that this creates
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