343 research outputs found
Segment Routing based Traffic Engineering
In modern networks, the increasing volume of network traffic and the diverse range of services with varying requirements necessitate the implementation of more advanced routing decisions and traffic engineering. This academic study proposes a QoS adaptive mechanism called âSepittoâ, which utilizes Segment routing protocols, specifically SRv6, to address network-traffic control and congestion avoidance. Sepitto leverages data-plane traffic to convey Linux Qdisc statistics, such as queue size, packet drops, and buffer occupancy, in each Linux-based virtual router. By incorporating this information, edge routers become aware of the current network status, enabling them to make informed decisions regarding traffic paths based on QoS classes. SRv6 is employed to direct traffic along desired paths, avoiding congested links and minimizing queuing delays and overall latency. Moreover, Sepitto offers network administrators an interface to customize decision-making processes based on their policies, assigning costs to network graph edges by associating the provided statistics to a certain cost. To incorporate these costs, the implementation employs the Dijkstra algorithm to determine the path with the lowest cost. Performance analysis of Sepitto reveals minimal overhead compared to traditional routing methods, while effectively mitigating network congestion. The results demonstrate that Sepitto reduces traffic round-trip time during congestion while maintaining differentiated treatment for various QoS classes
Chronology of the development of Active Queue Management algorithms of RED family. Part 1: from 1993 up to 2005
This work is the first part of a large bibliographic review of active queue management algorithms of the Random Early Detection (RED) family, presented in the scientific press from 1993 to 2023. The first part will provide data on algorithms published from 1993 to 2005
Scalable Schedule-Aware Bundle Routing
This thesis introduces approaches providing scalable delay-/disruption-tolerant routing capabilities in scheduled space topologies. The solution is developed for the requirements derived from use cases built according to predictions for future space topology, like the future Mars communications architecture report from the interagency operations advisory group. A novel routing algorithm is depicted to provide optimized networking performance that discards the scalability issues inherent to state-of-the-art approaches. This thesis also proposes a new recommendation to render volume management concerns generic and easily exchangeable, including a new simple management technique increasing volume awareness accuracy while being adaptable to more particular use cases. Additionally, this thesis introduces a more robust and scalable approach for internetworking between subnetworks to increase the throughput, reduce delays, and ease configuration thanks to its high flexibility.:1 Introduction
1.1 Motivation
1.2 Problem statement
1.3 Objectives
1.4 Outline
2 Requirements
2.1 Use cases
2.2 Requirements
2.2.1 Requirement analysis
2.2.2 Requirements relative to the routing algorithm
2.2.3 Requirements relative to the volume management
2.2.4 Requirements relative to interregional routing
3 Fundamentals
3.1 Delay-/disruption-tolerant networking
3.1.1 Architecture
3.1.2 Opportunistic and deterministic DTNs
3.1.3 DTN routing
3.1.4 Contact plans
3.1.5 Volume management
3.1.6 Regions
3.2 Contact graph routing
3.2.1 A non-replication routing scheme
3.2.2 Route construction
3.2.3 Route selection
3.2.4 Enhancements and main features
3.3 Graph theory and DTN routing
3.3.1 Mapping with DTN objects
3.3.2 Shortest path algorithm
3.3.3 Edge and vertex contraction
3.4 Algorithmic determinism and predictability
4 Preliminary analysis
4.1 Node and contact graphs
4.2 Scenario
4.3 Route construction in ION-CGR
4.4 Alternative route search
4.4.1 Yenâs algorithm scalability
4.4.2 Blocking issues with Yen
4.4.3 Limiting contact approaches
4.5 CGR-multicast and shortest-path tree search
4.6 Volume management
4.6.1 Volume obstruction
4.6.2 Contact sink
4.6.3 Ghost queue
4.6.4 Data rate variations
4.7 Hierarchical interregional routing
4.8 Other potential issues
5 State-of-the-art and related work
5.1 Taxonomy
5.2 Opportunistic and probabilistic approaches
5.2.1 Flooding approaches
5.2.2 PROPHET
5.2.3 MaxProp
5.2.4 Issues
5.3 Deterministic approaches
5.3.1 Movement-aware routing over interplanetary networks
5.3.2 Delay-tolerant link state routing
5.3.3 DTN routing for quasi-deterministic networks
5.3.4 Issues
5.4 CGR variants and enhancements
5.4.1 CGR alternative routing table computation
5.4.2 CGR-multicast
5.4.3 CGR extensions
5.4.4 RUCoP and CGR-hop
5.4.5 Issues
5.5 Interregional routing
5.5.1 Border gateway protocol
5.5.2 Hierarchical interregional routing
5.5.3 Issues
5.6 Further approaches
5.6.1 Machine learning approaches
5.6.2 Tropical geometry
6 Scalable schedule-aware bundle routing
6.1 Overview
6.2 Shortest-path tree routing for space networks
6.2.1 Structure
6.2.2 Tree construction
6.2.3 Tree management
6.2.4 Tree caching
6.3 Contact segmentation
6.3.1 Volume management interface
6.3.2 Simple volume manager
6.3.3 Enhanced volume manager
6.4 Contact passageways
6.4.1 Regional border deďŹnition
6.4.2 Virtual nodes
6.4.3 PathďŹnding and administration
7 Evaluation
7.1 Methodology
7.1.1 Simulation tools
7.1.2 Simulator extensions
7.1.3 Algorithms and scenarios
7.2 OďŹine analysis
7.3 Eliminatory processing pressures
7.4 Networking performance
7.4.1 Intraregional unicast routing tests
7.4.2 Intraregional multicast tests
7.4.3 Interregional routing tests
7.4.4 Behavior with congestion
7.5 Requirement fulďŹllment
8 Summary and Outlook
8.1 Conclusion
8.2 Future works
8.2.1 Next development steps
8.2.2 Contact graph routin
Performance Improvement of Multicommodity Flow of Tactile and Best Effort Packet in Internet Network
Enhancing User Experience by Extracting Application Intelligence from Network Traffic
Internet Service Providers (ISPs) continue to get complaints from users on poor experience for diverse Internet applications ranging from video streaming and gaming to social media and teleconferencing. Identifying and rectifying the root cause of these experience events requires the ISP to know more than just coarse-grained measures like link utilizations and packet losses. Application classification and experience measurement using traditional deep packet inspection (DPI) techniques is starting to fail with the increasing adoption of traffic encryption and is not cost-effective with the explosive growth in traffic rates. This thesis leverages the emerging paradigms of machine learning and programmable networks to design and develop systems that can deliver application-level intelligence to ISPs at scale, cost, and accuracy that has hitherto not been achieved before.
This thesis makes four new contributions. Our first contribution develops a novel transformer-based neural network model that classifies applications based on their traffic shape, agnostic to encryption. We show that this approach has over 97% f1-score for diverse application classes such as video streaming and gaming. Our second contribution builds and validates algorithmic and machine learning models to estimate user experience metrics for on-demand and live video streaming applications such as bitrate, resolution, buffer states, and stalls. For our third contribution, we analyse ten popular latency-sensitive online multiplayer games and develop data structures and algorithms to rapidly and accurately detect each game using automatically generated signatures. By combining this with active latency measurement and geolocation analysis of the game servers, we help ISPs determine better routing paths to reduce game latency. Our fourth and final contribution develops a prototype of a self-driving network that autonomously intervenes just-in-time to alleviate the suffering of applications that are being impacted by transient congestion. We design and build a complete system that extracts application-aware network telemetry from programmable switches and dynamically adapts the QoS policies to manage the bottleneck resources in an application-fair manner. We show that it outperforms known queue management techniques in various traffic scenarios. Taken together, our contributions allow ISPs to measure and tune their networks in an application-aware manner to offer their users the best possible experience
Dual Queue Coupled AQM: Deployable Very Low Queuing Delay for All
On the Internet, sub-millisecond queueing delay and capacity-seeking have
traditionally been considered mutually exclusive. We introduce a service that
offers both: Low Latency Low Loss Scalable throughput (L4S). When tested under
a wide range of conditions emulated on a testbed using real residential
broadband equipment, queue delay remained both low (median 100--300 s) and
consistent (99th percentile below 2 ms even under highly dynamic workloads),
without compromising other metrics (zero congestion loss and close to full
utilization). L4S exploits the properties of `Scalable' congestion controls
(e.g., DCTCP, TCP Prague). Flows using such congestion control are however very
aggressive, which causes a deployment challenge as L4S has to coexist with
so-called `Classic' flows (e.g., Reno, CUBIC). This paper introduces an
architectural solution: `Dual Queue Coupled Active Queue Management', which
enables balance between Scalable and Classic flows. It counterbalances the more
aggressive response of Scalable flows with more aggressive marking, without
having to inspect flow identifiers. The Dual Queue structure has been
implemented as a Linux queuing discipline. It acts like a semi-permeable
membrane, isolating the latency of Scalable and `Classic' traffic, but coupling
their capacity into a single bandwidth pool. This paper justifies the design
and implementation choices, and visualizes a representative selection of
hundreds of thousands of experiment runs to test our claims.Comment: Preprint. 17pp, 12 Figs, 60 refs. Submitted to IEEE/ACM Transactions
on Networkin
Air Traffic Management Abbreviation Compendium
As in all fields of work, an unmanageable number of abbreviations are used today in aviation for terms, definitions, commands, standards and technical descriptions. This applies in general to the areas of aeronautical communication, navigation and surveillance, cockpit and air traffic control working positions, passenger and cargo transport, and all other areas of flight planning, organization and guidance. In addition, many abbreviations are used more than once or have different meanings in different languages.
In order to obtain an overview of the most common abbreviations used in air traffic management, organizations like EUROCONTROL, FAA, DWD and DLR have published lists of abbreviations in the past, which have also been enclosed in this document. In addition, abbreviations from some larger international projects related to aviation have been included to provide users with a directory as complete as possible. This means that the second edition of the Air Traffic Management Abbreviation Compendium includes now around 16,500 abbreviations and acronyms from the field of aviation
Video Conference as a tool for Higher Education
The book describes the activities of the consortium member institutions in the framework of the TEMPUS IV Joint Project ViCES - Video Conferencing Educational Services (144650-TEMPUS-2008-IT-JPGR). In order to provide the basis for the development of a distance learning environment based on video conferencing systems and develop a blended learning courses methodology, the TEMPUS Project VICES (2009-2012) was launched in 2009. This publication collects the conclusion of the project and it reports the main outcomes together with the approach followed by the different partners towards the achievement of the project's goal. The book includes several contributions focussed on specific topics related to videoconferencing services, namely how to enable such services in educational contexts so that, the installation and deployment of videoconferencing systems could be conceived an integral part of virtual open campuses
PRAM: Penalized Resource Allocation Method for Video Services
The human visual system response to picture quality degradation due to packet loss is very different from the responses of objective quality measures. While video quality due to packet loss may be impaired by at most for one Group of Pictures (GOP), its subjective quality degradation may last for several GOPs. This has a great impact on resource allocation strategies, which normally make decisions on instantaneous conditions of multiplexing buffer. This is because, when the perceptual impact of degraded video quality is much longer than its objective degradation period, any assigned resources to the degraded flow is wasted. This paper, through both simulations and analysis shows that, during resource allocation, if the quality of a video stream is significantly degraded, it is better to penalize this degraded flow from getting its full bandwidth share and instead assign the remaining share to other flows preventing them from undergoing quality degradation
Construction, Operation and Maintenance of Network System(Junior Level)
This open access book follows the development rules of network technical talents, simultaneously placing its focus on the transfer of network knowledge, the accumulation of network skills, and the improvement of professionalism. Through the complete process from the elaboration of the theories of network technology to the analysis of application scenarios then to the design and implementation of case projects, readers are enabled to accumulate project experience and eventually acquire knowledge and cultivate their ability so as to lay a solid foundation for adapting to their future positions. This book comprises six chapters, which include âGeneral Operation Safety of Network System,â âCabling Project,â âHardware Installation of Network System,â âBasic Knowledge of Network System,â âBasic Operation of Network System,â and âBasic Operation and Maintenance of Network System.â This book can be used for teaching and training for the vocational skills certification of network system construction, operation, and maintenance in the pilot work of Huaweiâs â1+Xâ Certification System, and it is also suitable as a textbook for application-oriented universities, vocational colleges, and technical colleges. In the meantime, it can also serve as a reference book for technicians engaged in network technology development, network management and maintenance, and network system integration. As the worldâs leading ICT (information and communications technology) infrastructure and intelligent terminal provider, Huawei Technologies Co., Ltd. has covered many fields such as data communication, security, wireless, storage, cloud computing, intelligent computing, and artificial intelligence. Taking Huawei network equipment (routers, switches, wireless controllers, and wireless access points) as the platform, and based on network engineering projects, this book organizes all the contents according to the actual needs of the industry
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