Search

Currently, the multiprotocol label switching (MPLS) standard is extremely prevalent. By exploiting the features provided by MPLS technology, a range of services, including IP telephony, have enhanced their overall performance. However, due to the size of the packet header, the IP telephony service consumes a significant portion of the MPLS network's available bandwidth. For instance, in IP telephony over MPLS networks, the packet header might account for as much as 80% of lost time and bandwidth. Designers working on IP telephony are making substantial efforts to address this issue. This study contributes to current efforts by proposing a novel approach called Tel-MPLS, which involves IP telephony over MPLS. TelMPLS approach uses the superfluous fields in the IP telephony packet's header to retain the packet data, therefore lowering or zeroing the IP telephony packet's payload. Tel-MPLS is an approach that significantly reduces the bandwidth of IP telephony MPLS networks. According to the findings, the Tel-MPLS approach is capable of reducing the amount of bandwidth that is lost by 12% when using the G.729 codec. [ABSTRACT FROM AUTHOR]

Generalized multiprotocol Label Switching (GMPLS) is a set of rules which is used in various layers like the Wavelength Division Multiplexing (WDM) layer, Time Division Multiplexing (TDM) layer, etc. to generalize the concepts of labels of Multiprotocol Label Switching networks. A block in call occurs when number of requests is more than the servers and waiting rooms. This call blocking is the very important parameter and can be calculated in terms of probability. There are a number of models to calculate the call blocking probability like Erlang B, Erlang C, etc. This paper suggests a novel, efficient and less – complex model which minimize the call blocking to very much extent for GMPLS networks. This model deals with the factors like number of wavelengths, number of links, traffic intensity, etc. which can help in reducing the call blocking probability and give better results. In this paper, the call-blocking probability is also compared with number of links by considering different wavelengths. A comparison of call-blocking probability of proposed model is also analysed. This paper deals with blocking probability optimization in GMPLS Networks using Fredericks approach. We have used peakedness factor from Fredericks approach in Engset's formula for this optimization." [ABSTRACT FROM AUTHOR]

In this paper, we have proposed a Multiservice Provisioning Optical Code Switching (OCS) method for GMPLS networks, which uses Optical-Code-Division-Multiplexing (OCDM) across every lightpath of a wavelength division multiplexing system. We also presented the router architecture for the GMPLS multiservice network. In this method, the Multi Length Variable Weight Optical Orthogonal Code (MLVW-OOC) is used to multiplex each class (two-class system) service connection to a wavelength as an OCDM signature series. First, the fiber bandwidth has been classified into several wavebands, whose wavelengths are considered for a specific service class depending on the characteristics of that service class. The codes corresponding to the service class are also given in this manuscript. Erlang's traffic behavior of the network model is used to evaluate the system performance as well as to obtain the probability density functions (PDF) of the number of labels oocupied by a link. We have also evaluated the PDF for the number of labels occupied in each wavelength. Further, we have evaluated the performance of the network in terms of the probability of outage, blocking probability, and the end-to-end (EE) bit error rate (BER) of a connection. The results indicate that interfering users perform better with longer-weight code words. Moreover, with the increase in the number of intermediate OCS routers, EE BER is increased, and it is found that by constraining the number of connected paths, performance can be improved. [ABSTRACT FROM AUTHOR]

In future generation networks, data protection is a crucial necessity particularly when information is sent on a system. Network protection has three objectives known as discretion, reliability and accessibility. The most common procedure exploited to attain this ambition is encryption. The Generalized Multi Protocol Label Switched (GMPLS) optical networks are designed to survive Internet Protocol's (IPʹs) unreliable delivery. In this paper, GMPLS network is proposed with random users and then the data protection algorithms have been analyzed on proposed GMPLS optical network. The various algorithms involve Rivest Shamir Adleman (RSA) algorithm and Advanced Encryption Standard (AES) algorithm. The considered algorithms are very popular but have not been implemented on GMPLS optical networks in the literature which shows the novelty of the presented work. The network performance is compared for these algorithms in terms of various parameters like blocking probability and latency. The results reveal that RSA reduces the blocking probability < 0.005 and latency < 0.007 ms. This shows that RSA gives better performance than AES algorithm and enhance the quality of service considering blocking probability, latency and overheads in GMPLS optical networks leading to enhanced data protection. [ABSTRACT FROM AUTHOR]

This research problem discusses the occurrence during the MPLS service tunneling process which often looping during the data transmission process, especially in Layer 2-OSI, where data packets will be sent back to the recipient so that data packets do not reach their destination or because of problems with the traffic of sending data. Looping Prevention is one of the proposed methods in this research that occur in tunnel service causes looping. This method is applied by analyzing traffic based on MAC addresses obtained from service verification results so that the cause of looping is known. The results of looping protection methods get an average throughput and delay, when the process of uploading traffic of 16 MB gets 119.3 bps for throughput and delay of 5.9 ms, and when downloading gets throughput of 185.33 bps and delay 6.5 ms. Then, the process of uploading traffic of 32 MB get upload throughput of 129 bps and delay 5.2 ms, and when downloading gets a throughput of 232.66 bps and gets a delay of 4.13 ms. All values obtained are in the category very well based on the standard category TIPHON. [ABSTRACT FROM AUTHOR]

Cloud computing services and real-time Internet applications have spawned a large variety of potential requirements for quality of service (QoS), especially the latency and connection setup time. However, with the optical networks develop toward to larger scale, wider coverage and more users access, conventional resource reservation protocol traffic engineering (RSVP-TE) signal hop by hop transmission scheme cannot meet the requirements of these new applications for real-time dynamic services and fast restoration with long propagation delays. This paper proposes a novel RSVP-TE bilateral-recursive region re-routing crankback mechanism (BRCB) base on distributed path computation element (PCE) for generalized multiprotocol label switching (GMPLS) optical networks. In this mechanism, the backtracking nodes re-route and update the region routing paths which bypass the crankback and re-routing failure nodes when crankback occurs. It not only reduces the influencing factors of the scale of network, signaling crankback position and frequency to path connection setup time, but also avoids the backtracking of teardown messages. [ABSTRACT FROM AUTHOR]

The Next Generation Network (NGN) architecture was proposed for delivering various multimedia services with guaranteed quality. For this reason, the elements of the IP Multimedia Subsystem (IMS) concept (an important part of 4G/5G/6G mobile networks) are used in its service stratum. This paper presents comprehensive research on how the parameters of an IMS/NGN network and traffic sources influence mean Call Set-up Delay (E(CSD)) and mean Call Disengagement Delay (E(CDD)), a subset of standardized call processing performance (CPP) parameters, which are significant for both network users and operators. The investigations were performed using our analytical traffic model of a multidomain IMS/NGN network with Multiprotocol Label Switching (MPLS) technology applied in its transport stratum, which provides transport resources for the services requested by users. The performed experiments allow grouping network and traffic source parameters into three categories based on the strength of their effect on E(CSD) and E(CDD). These categories reflect the significance of particular parameters for the network operator and designer (most important, less important and insignificant). [ABSTRACT FROM AUTHOR]

The magnon propagation length (MPL) is one of the crucial factors to govern spin transport in a magnetic material. Here, we determine MPL ($\xi$) in compensated ferrimagnetic Gd3Fe5O12 (GdIG) thin films at room temperature by investigating longitudinal spin Seebeck effect (LSSE) in Gd3Ga5O12 (GGG)/GdIG($t$)/Pt (5 nm) heterostructures with different thicknesses ($t$) of the GdIG film. All films possess in-plane (IP) magnetic easy axis, and the compensation temperature shifts down to lower temperature with decreasing GdIG thickness. At room temperature, the LSSE signal is rather constant with thickness between $t = 221$ and 89 nm, but drops significantly below $t = 50$ nm. By fitting the thickness dependence of the LSSE voltage to a modified atomistic spin model considering the influence of saturation magnetization, we obtain $\xi $ = 45 nm ± 8 nm for GdIG thin films at room temperature. The MPL of GdIG is much shorter than that of Y3Fe5O12 films ($\xi $ ~90–140 nm), but higher than that of Fe3O4 films ($\xi $ ~20 nm). The obtained value of $\xi $ explains the drop in the LSSE voltage in GdIG films when the film thickness is reduced below 50 nm, knowledge of which is also essential to the design of spincaloritronic devices based on GdIG films. [ABSTRACT FROM AUTHOR]

Summary: This paper proposes a solution to the problem of switching between different network paths. We choose to switch between multiprotocol label switching (MPLS) and software‐defined wide area networking (SD‐WAN) connections specifically as they are the mainstream currently. The solution should maintain a service license agreement (SLA) while choosing SD‐WAN as long as possible to save cost. Therefore, a deep reinforcement learning solution is proposed that predicts when to switch based on bandwidth availability and quality of service (QoS) parameters like jitter and delay. Results show that double deep Q learning in combination with these parameters are suitable to make a sophisticated decision on link switching between MPLS and SD‐WAN. [ABSTRACT FROM AUTHOR]

Compositional Optimization (CompOpt) was recently proposed for optimization of discrete-event systems of systems. A modular optimization model allows CompOpt to divide the optimization into separate sub-problems, mitigating the state space explosion problem. This paper presents the Modular Optimization Learner (MOL), a method that interacts with a simulation of a system to automatically learn these modular optimization models. MOL uses a modular learning that takes as input a hypothesis structure of the system and uses the provided structural information to split the acquired learning into a set of modules, and to prune parts of the search space. Experiments show that modular learning reduces the state space by many orders of magnitude compared to a monolithic learning, which enables learning of much larger systems. Furthermore, an integrated greedy search heuristic allows MOL to remove many sub-optimal paths in the individual modules, speeding up the subsequent optimization. Note to Practitioners—Automation systems are becoming increasingly large and complex and the automation of more and more advanced tasks often requires the coordination of multiple subsystems. Optimization can have a great impact on the efficiency of these systems in terms of cost and operation speed. Finding optimal solutions is, however, a difficult task. As the number of tasks and subsystems of the automation system increases, the search space of the optimization problems tends to grow exponentially. Compositional Optimization (CompOpt) is a method specifically designed for the optimization of large-scale automation systems. A challenge with the application of CompOpt is that it takes as input a specific type of optimization model that divides the system into subsystems; like machines, vehicles, etc. Formulating these models requires a high level of expertise and system knowledge. This paper addresses this challenge with an algorithm that learns these models from a simulation of the system. The simulation can be implemented in any software as long as a suitable interface exists or can be constructed. To divide the learning into subsystems, the algorithm uses an initial plant structure hypothesis (PSH). This can be viewed as a meta-model that includes known structural information, such as the number of subsystems and which actions that affect each subsystem. The more structural information that is added to PSH, the more efficient the learning and subsequent optimization will be. The purpose of this is to reduce the level of expertise and system knowledge needed in the application of optimization, to simplify the transition to Industry 4.0. [ABSTRACT FROM AUTHOR]

Coverage performance is very important for operators when commercializing NR networks due to its direct impact on service quality as well as CAPEX and OPEX. Compared to LTE, NR systems may operate at higher frequency bands, resulting in larger path loss and worse coverage performance. In this article, potential coverage issues for NR networks are discussed. Through link budget analysis, the gaps between baseline and target performance for typical NR physical channels are described; then the bottleneck channels are identified, including PUSCH, PUCCH, and PRACH. This article mainly focuses on PUSCH coverage enhancement, and potential solutions are discussed in a comprehensive manner. On top of the potential solutions, four joint schemes, which take feasibility as well as specification impact into consideration, are proposed for VoIP and eMBB services to further improve the coverage performance. [ABSTRACT FROM AUTHOR]

This article shows the quality of services in a wireless swarm of drones that form an ad hoc network between them Fly Ad Hoc Networks (FANET). Each drone has the ability to send and receive information (like a router); and can behave as a hierarchical node whit the intregration of three protocols: Multiprotocol Label Switch (MPLS), Fast Hierarchical AD Hoc Mobile (FHAM) and Internet Protocol version 6 (IPv6), in conclusion MPLS + FHAM + IPv6. The metrics analyzed in the FANET are: delay, jitter, throughput, lost and sent packets/received. Testing process was carried out with swarms composed of 10, 20, 30 and 40 units; In this work, the stage with 40 drones was analyzed showing registration processes, and sent messages sequences between different drones that were part of the same swarm. A special analysis about the traffic between drones (end-to-end) was carried out, as well as the possible security flaws in each drone and the current status and future trends in real services. Regarding future trends, in a real environment, we took as a starting point, metrics results obtained in the simulation (positive according to the obtained results). These results gave us a clear vision of how the network will behave in a real environment with the aim to carry out the experiment on a physical level in the near future. This work also shows the experience quality from the service quality metrics obtained through a mathematical model. This quality of experience model will allow us to use it objectively in the agricultural sector, which is a great interest area and is where we are working with drones. Finally in this article we show our advances for a business model applied to the aforementioned agricultural sector, as well as the data analysis and services available to the end customer. These services available to the end customer have been classified into a basic, medium, advanced and plus level. [ABSTRACT FROM AUTHOR]

Recently, there has been an increasing need for new applications and services such as big data, blockchains, vehicle-to-everything (V2X), the Internet of things, 5G, and beyond. Therefore, to maintain quality of service (QoS), accurate network resource planning and forecasting are essential steps for resource allocation. This study proposes a reliable hybrid dynamic bandwidth slice forecasting framework that combines the long short-term memory (LSTM) neural network and local smoothing methods to improve the network forecasting model. Moreover, the proposed framework can dynamically react to all the changes occurring in the data series. Backbone traffic was used to validate the proposed method. As a result, the forecasting accuracy improved significantly with the proposed framework and with minimal data loss from the smoothing process. The results showed that the hybrid moving average LSTM (MLSTM) achieved the most remarkable improvement in the training and testing forecasts, with 28% and 24% for long-term evolution (LTE) time series and with 35% and 32% for the multiprotocol label switching (MPLS) time series, respectively, while robust locally weighted scatter plot smoothing and LSTM (RLWLSTM) achieved the most significant improvement for upstream traffic with 45%; moreover, the dynamic learning framework achieved improvement percentages that can reach up to 100%. [ABSTRACT FROM AUTHOR]

Future communication networks are expected to be highly automated, disburdening human operators of their most complex tasks. While the first powerful and automated network analysis tools are emerging, existing tools provide only limited and inefficient support of reasoning about failure scenarios. We present P-REX, a fast what-if analysis tool, that allows us to test important reachability and policy-compliance properties even under an arbitrary number of failures and in polynomial-time, i.e., without enumerating all failure scenarios (the usual approach today, if supported at all). P-REX targets networks based on Multiprotocol Label Switching (MPLS) and its Segment Routing (SR) extension which feature fast rerouting mechanisms with label stacks. In particular, P-REX allows to reason about recursive backup tunnels, by supporting potentially infinite state spaces. As P-REX directly operates on the actual dataplane configuration, i.e., forwarding tables, it is well-suited for debugging. Our tool comes with an expressive query language based on regular expressions. We also report on an industrial case study and demonstrate that our tool can perform what-if reachability analyses on average in about 5 seconds for a 24-router network with over 250,000 MPLS forwarding rules. This is a significant improvement to an earlier prototype of our tool presented in the conference version of our paper where the verification took on average about 1 hour. [ABSTRACT FROM AUTHOR]

Many organizations nowadays have multiple sites at different geographic locations. Typically, transmitting massive data among these sites relies on the interconnection service offered by ISPs. Segment Routing over IPv6 (SRv6) is a new simple and flexible source routing solution which could be leveraged to enhance interconnection services. Compared to traditional technologies, e.g., physical leased lines and MPLS-VPN, SRv6 can easily enable quick-launched interconnection services and significantly benefit from traffic engineering with SRv6-TE. To parse the SRv6 packet headers, however, hardware support and upgrade are needed for the conventional routers of ISP. In this paper, we study the problem of SRv6 incremental deployment to provide a more balanced interconnection service from a traffic engineering view. We formally formulate the problem as an SRID problem with integer programming. After transforming the SRID problem into a graph model, we propose two greedy methods considering short-term and long-term impacts with reinforcement learning, namely GSI and GLI. The experiment results using a public dataset demonstrate that both GSI and GLI can significantly reduce the maximum link utilization, where GLI achieves a saving of 59.1% against the default method. [ABSTRACT FROM AUTHOR]

Network operators cannot change their foot-print to upgrade the entire network to support SDN from scratch. Hence, network operators adapted the original SDN concept into a hybrid SDN approach to have a pragmatic, evolutionary, and economically viable solution. This article tests an SDN architecture based on a hierarchical structure of a Software-Defined Transport Networking (SDTN) controller, which deals with the end-to-end service provision and topology collection on top of a set of SDN controllers for each technological domain. The authors demonstrate L3/L2 VPN service deployment using an underlay multi-domain IP/Optical network in a field trial. The approach allows a service provider to migrate brownfield scenarios into SDN domains using programmatic interfaces. [ABSTRACT FROM AUTHOR]

This article presents an active ball joint mechanism (ABENICS) enhanced by interactions of spherical gears. The gear-based joint drives three rotational degrees of freedom (RDoF) without slippage. The capabilities were inspired by the unique interactions between two different innovative gears [the cross spherical gear (CS-gear) and monopole gear (MP-gear)] and the superimposition of those interactions by the CS-gear's quadrature spherical tooth structure. One MP-gear constrains two of the three RDoF of the CS-gear. The driving module which drives the MP-gear converts this “constraint” into a “drive” and drives the CS-gear with two RDoF. The CS-gear orthogonally superimposes the interactions caused by two MP-gears to achieve three RDoF driving forces. The principle was revealed by analyzing an equivalent linkage modeled on the mechanism of ABENICS. The linkage also led to the kinematics and torque equations. The theory and physical characteristics of ABENICS were verified in comprehensive and continuous positioning experiments on manufactured prototypes. The flexibility of the actuator placement was also verified in different configurations of the driving modules. The active ball joint, ABENICS can transmit high torque and reliable positioning in three RDoF without an orientation sensor, which applies to robot joints and orientation control mechanisms. [ABSTRACT FROM AUTHOR]

The hardcore model on a graph $G$ with parameter $\lambda > 0$ is a probability measure on the collection of all independent sets of $G$ , that assigns to each independent set $I$ a probability proportional to $\lambda ^{|I|}$. In this paper we consider the problem of estimating the parameter $\lambda $ given a single sample from the hardcore model on a graph $G$. To bypass the computational intractability of the maximum likelihood method, we use the maximum pseudo-likelihood (MPL) estimator, which for the hardcore model has a surprisingly simple closed form expression. We show that for any sequence of graphs $\{G_{N}\}_{N \geq 1}$ , where $G_{N}$ is a graph on $N$ vertices, the MPL estimate of $\lambda $ is $\sqrt {N}$ -consistent (that is, it converges to the true parameter at rate $1/\sqrt {N}$), whenever the graph sequence has uniformly bounded average degree. We then extend our methods to obtain estimates for the vector of activity parameters in general $H$ -coloring models, in which restrictions between adjacent colors are encoded by a constraint graph $H$. These constitute an important class of Markov random fields that includes all hard-constraint models, which arise in a broad array of fields including combinatorics, statistical physics, and communication networks. Given a single sample from an $H$ -coloring model, we derive sufficient conditions under which the MPL estimate is $\sqrt {N}$ -consistent. Moreover, we verify the sufficient conditions for $H$ -coloring models for which there is at least one ‘unconstrained’ color (that is, there exists at least one vertex in the constraint graph $H$ that is connected to all vertices), as long as the graph sequence has uniformly bounded average degree. This applies to many $H$ -coloring examples such as the Widom-Rowlinson and multi-state hard-core models. On the other hand, for the $q$ -coloring model, which falls outside this class, we show that the condition can fail and consistent estimation may be impossible even for graphs with bounded average degree. Nevertheless, we show that the MPL estimate is $\sqrt {N}$ -consistent in the $q$ -coloring model when $\{G_{N}\}_{N \geq 1}$ has bounded average double neighborhood. The presence of hard constraints, as opposed to soft constraints, leads to new challenges, and our proofs entail applications of the method of exchangeable pairs as well as combinatorial arguments that employ the probabilistic method. [ABSTRACT FROM AUTHOR]

Optical multilayer optimization periodically reorganizes layer 0-1-2 network elements to handle both existing and dynamic traffic requirements in the most efficient manner. This delays the need for adding new resources in order to cope with the evolution of the traffic, thus saving CAPEX. The focus of this paper is on Layer 2, i.e., on capacity reoptimization at the optical transport network (OTN) layer when routes (e.g., LSPs in MPLS networks) are making unnecessarily long detours to evade congestion. Reconfiguration into optimized routes can be achieved by re-defining the routes, one at a time, so that they use the vacant resources generated by the disappearance of services using part of a path that transits the congested section. To maintain the Quality of Service, it is desirable to operate under a Make-Before-Break (MBB) paradigm, with the minimum number of reroutings. The challenge is to determine the best rerouting order while minimizing the bandwidth requirement. We propose an exact and scalable optimization model for computing a minimum bandwidth rerouting scheme subject to MBB in the OTN layer of an optical network. Numerical results show that we can successfully apply it on networks with up to 30 nodes, a very significant improvement with respect to the state of the art. We also provide some reoptimization analysis in terms of the bandwidth requirement vs. the number of reroutings. [ABSTRACT FROM AUTHOR]

Nowadays, the VPN (Virtual Private Network) technique is one of the most common and important implementations in IT and other companies. VPN technology is divided into two categories: (i) overlay VPN and (ii) peer-to-peer VPN. In overlay VPN, ATM and frame relay are included, and peer-to-peer VPN includes IP-routing. VPN technology is becoming more and more important because of its security, convenience of working with VPN, real-time application, and low construction cost. When compared to traditional VPN, MPLS VPN (Multiprotocol Label Switching) is a good solution for real-time. MPLS VPN is an advanced technology, and it has advanced features. MPLS VPN has functions like FEC, VRF, MPBGP, and VPNv4. These functions are used to overcome the disadvantages of traditional VPNs. The disadvantages of traditional VPNs are (i) complex management, (ii) lack of availability, (iii) complex implementation, (iv) expansibility, and (v) customer address overlapping. In this paper, the implementation of the MPLS layer 3 VPN technique is used to connect and share information between different branches of different customers which are geographically separated. Here, a private IP address instead of a public IP address is used to connect and share the information. The MPLS VPN technique is used to provide flexibility for the customer through their ISP (Internet Service Provider). [ABSTRACT FROM AUTHOR]

We consider protection switching in an IP over optical network. There is IP Fast Reroute Loop-free Alternates (IP FRR LFA) at the IP layer, and protection switching at the optical layer. Our network model assumes a completely connected IP network over an optical ring network that is required to protect a predetermined fraction of network bandwidth. This model leads to analytical formulas on network protection costs which we show are accurate. We also show that network cost is at or near zero when the network is required to protect at most 33% of traffic. A cost comparison to networks using MPLS Fast Reroute (MPLS FRR) further indicates that LFA is a feasible protection mechanism. [ABSTRACT FROM AUTHOR]

Video prediction is challenging, due to the pixel-level precision requirement and the difficulty in capturing scene dynamics. Most approaches tackle the problems by pixel-level reconstruction objectives and two decomposed branches, which still suffer from blurry generations or dramatic degradations in long-term prediction. In this paper, we propose a Motion-Aware Feature Enhancement (MAFE) network for video prediction to produce realistic future frames and achieve relatively long-term predictions. First, a Channel-wise and Spatial Attention (CSA) module is designed to extract motion-aware features, which enhances the contribution of important motion details during encoding, and subsequently improves the discriminability of attention map for the frame refinement. Second, a Motion Perceptual Loss (MPL) is proposed to guide the learning of temporal cues, which benefits to robust long-term video prediction. Extensive experiments on three human activity video datasets: KTH, Human3.6M, and PennAction demonstrate the effectiveness of the proposed video prediction model compared with the state-of-the-art approaches. [ABSTRACT FROM AUTHOR]

Traffic engineering is an important concept that allows Internet Service Providers (ISPs) to utilize their existing routing hardware more efficiently. One technology that can be used is Segment Routing (SR). In this paper, we address the use of SR to increase the resilience against failure scenarios. In addition, we develop solutions that are manageable and, thus, deployable in a tier 1 ISP network. We propose a post-convergence aware SR based optimization model. With it, we can proactively find a single SR configuration that is beneficial in all predefined failure scenarios, including single link failures, shared risk link group failures, and node failures. In addition to this use-case, we also extend the optimization model to include other important practical requirements such as keeping the number of SR tunnels to a minimum, avoiding arbitrary traffic splitting, or meeting latency bounds. We evaluate our approaches with recently measured data from a tier 1 ISP and show that we can improve over state of the art routing approaches. [ABSTRACT FROM AUTHOR]

Many contemporary networks, such as datacenters, optical networks, and MultiProtocol Label Switching (MPLS) make it impossible or inefficient to supply a traffic flow with a certain bandwidth need via a single network link. In these instances, it is often feasible to increase network bandwidth utilization by distributing traffic over numerous efficient channels. While employing numerous pathways for the same data flow improves network efficiency, it uses costly forwarding resources from network nodes, such as TCAM, Ethernet/MPLS switch entries and optical switch wavelengths/lightpaths. In this work, we identify many challenges related to dividing a traffic flow across several pathways while using as few forwarding resources as possible, and we offer efficient methods for handling these difficulties. [ABSTRACT FROM AUTHOR]

The call blocking is the most vital factor in generalized multiprotocol label switching (GMPLS) Networks. Call blocking depends upon many factors such as traffic intensity, number of servers and number of links. Call blocking performance for GMPLS networks has been calculated in this paper by using a proposed mathematical model. The proposed model investigates the dependency of probability of call blocking upon the number of wavelengths and number of links. In the suggested model, the blocking performance of GMPLS network is improved. [ABSTRACT FROM AUTHOR]

Mobile Ad Hoc Network (MANET) is a wireless network that does not have any fixed structure. MANET is a collection of independent mobile nodes that can communicate with each other through radio waves. In conventional Internet Protocol (IP) forwarding, each router creates forwarding decision on the basis of IP header information. The router has to analyse the packet and routing table at each hop to take the decision for data transmission. Since, inappropriate decisions in data transmission causes delay in packet delivery. This can be overcome with the help of a special feature of Multiprotocol Label Switching (MPLS) called Label switching. MPLS is a switching mechanism that plays a good role in routing, switching and forwarding using small labels. The MPLS is integrated into MANET to improve network performance. In this paper, an effective routing strategy is introduced to reduce the transmission time between routers during the data transmission. Here the Ad Hoc On-Demand Distance Vector (AODV) with Biogeography Based Optimization (BBO) based routing method is used to identify the optimal route among the routers of the MPLS based MANET. The proposed methodology is named as AODV-BBO. Three different objective functions are considered in this routing strategy viz., residual energy, distance and number of hops. Moreover, the rerouting is performed when the node or link failure occurs in the network. This rerouting is used to overcome the packet drop through the MPLS based MANET. The performance of AODV-BBO methodology is analysed in terms of percentage of alive nodes, dead nodes, energy consumption, end to end delay and bandwidth. The performance of the AODV-BBO methodology is compared with two existing methods P2R2 and PS-ROGR. Result showed that, the energy consumption of the AODV-BBO methodology with 400 nodes is 536.52 J, which is less compared to the PS-ROGR method. [ABSTRACT FROM AUTHOR]

Segment Routing (SR) is a source routing paradigm which is widely used in Traffic Engineering (TE). By using SR, a node steers a packet through an ordered list of instructions called segments. By some extensions of interior gateway protocol, SR can be applied to IP/MPLS or IPv6 network without signal protocol. SR over IPv6 (SRv6) is attracting wide attention because of its interoperation ability with IPv6. However, upgrading the existing IPv6 network directly to a full SRv6 one can be difficult, because large-scale equipment replacement or software upgrade may cause economic and technical problems. TE in partially deployed SR network is becoming a hot research topic. In this paper, we propose the TE algorithm Weight Adjustment-SRTE (WA-SRTE) in partially deployed SRv6 network, in which SRv6 capable nodes are dispersedly deployed. Our objective is to minimize the network’s maximum link utilization. WA-SRTE converts the TE problem into a Deep Reinforcement Learning problem and optimizes the OSPF weight, SRv6 node deployment and traffic paths simultaneously. Besides, traffic variation is also considered and we use a representative Traffic Matrix (TM) to epitomize the traffic characteristics over a period of time. Experiments demonstrate that with 20% to 40% of the SRv6 nodes deployed, we can achieve TE performance as good as in a full SR network for the experiment topologies. The results with WA remarkably outperform the results without it. Our algorithm also gets near-optimal results with changing traffic. [ABSTRACT FROM AUTHOR]

In this paper, we present an open source Software-Defined Networking (SDN) based emulation platform called Timber. We aim to provide the research community with an experimental tool for the design and evaluation of the new Quality of Experience (QoE) management and monitoring procedures for video streaming. To this aim, the main functionalities of Timber include: i) an SDN application for taking QoE-aware management decisions; ii) an SDN controller to monitor the network’s QoS (Quality of Service) and implement network management actions, such as network slicing and Multiprotocol Label Switching (MPLS) based prioritization operations; iii) a complete video streaming application including a multimedia server and a DASH-based client video player; iv) a user-end probe at the client video player to monitor QoE-related video application parameters, which are stored in a database that can be accessed by the SDN application; v) data analysis tools, which enable easy data visualization of measured QoS and QoE metrics as well as execution of statistical analysis of experimental results. In this article, we introduce and describe the main characteristics and functionalities of Timber as well as the implementation details. Finally, we provide experimental results of a video streaming scenario to demonstrate the capability of Timber to implement and test QoE-aware management approaches. [ABSTRACT FROM AUTHOR]

Rectangular grid graph (RGG) and diagonal grid graph (DGG) are induced subgraphs of a rectangular or diagonal grid, respectively. Their $k$ -coloring problem has direct applications in printing contact/via layouts by multipatterning lithography (MPL). However, the problem in general is computationally difficult for $k>2$ , while it remains an open question on grid graphs due to their regularity and sparsity. On the other hand, directed self-assembly (DSA) technique can work with MPL to optimize the graph by grouping neighboring vertices such that $k$ can be reduced, but the problem of deploying the grouping for coloring is even more intractable. In this paper, we study both of the $k$ -coloring problems, with and without DSA grouping, on RGG and DGG. Without grouping, a complete $k$ -coloring analysis is conducted and particularly the NP-completeness of 3-coloring on a diagonal grid is proved. When considering grouping, we present a 3-coloring solution and prove the NP-completeness to solve the problem of $k=2$. [ABSTRACT FROM AUTHOR]

Featured with simple topology and easy realization of zero-voltage-switching, the Class E dc–dc converter is preferable for very high-frequency application. In this article, a multipower-level (MPL) hysteresis control is proposed for the Class E dc–dc converter, in which, multiple switching frequencies are selected for obtaining multiple input power levels, and the two adjacent input powers closest to the load power are chosen to synthesize the load power. Compared with the on–off control, which has only two input power levels, i.e., the input power in on mode and zero power in off mode, the MPL hysteresis control reduces the modulation frequency, and thus reducing the mode transition losses. Meanwhile, the conduction losses are also reduced. As a result, the efficiency of the converter is greatly improved. The parameters design and the switching frequencies selection for the Class E dc–dc converter with MPL hysteresis control are presented. Finally, a prototype of 10-W Class E dc–dc converter with 9–18 V input is fabricated and tested in the lab, and the experimental results are provided to verify the effectiveness of the proposed MPL hysteresis control scheme. [ABSTRACT FROM AUTHOR]

Content Distribution and End-to-End Monitoring with Set Cover by Pairs Digital content is housed at data centers located on nodes of a data network. Consumers of this content are also located on network nodes. Content flows from a data center to a consumer on a path defined by a routing protocol, such as open shortest path first. A pair of data centers is said to feasibly serve content to a consumer if there are disjoint paths from each data center to the consumer. In "Near-Optimal Disjoint-Path Facility Location Through Set Cover by Pairs," Johnson, Breslau, Diakonikolas, Duffield, Gu, Hajiaghayi, Karloff, Resende, and Sen study this problem when the goal is to minimize the number of required data centers to serve a set of consumers. They also study another facility location problem that arises in network traffic monitoring. Both problems are modeled as a set cover-by-pairs problem. The authors provide complexity results, a new lower-bounding integer programming formulation, and several heuristics. The lower bounds are easily computed with a commercial MIP solver and validate the claim of near-optimality of their heuristics. In this paper, we consider two special cases of the "cover-by-pairs" optimization problem that arises when we need to place facilities so that each customer is served by two facilities that reach it by disjoint shortest paths. These problems arise in a network traffic-monitoring scheme proposed by Breslau et al. and have potential applications to content distribution. The "set-disjoint" variant applies to networks that use the open shortest path first routing protocol, and the "path-disjoint" variant applies when multiprotocol label switching routing is enabled, making better solutions possible at the cost of greater operational expense. Although we can prove that no polynomial-time algorithm can guarantee good solutions for either version, we are able to provide heuristics that do very well in practice on instances with real-world network structure. Fast implementations of the heuristics, made possible by exploiting mathematical observations about the relationship between the network instances and the corresponding instances of the cover-by-pairs problem, allow us to perform an extensive experimental evaluation of the heuristics and what the solutions they produce tell us about the effectiveness of the proposed monitoring scheme. For the set-disjoint variant, we validate our claim of near-optimality via a new lower-bounding integer programming formulation. Although computing this lower bound requires solving the NP-hard hitting set problem and can underestimate the optimal value by a linear factor in the worst case, it can be computed quickly by CPLEX, and it equals the optimal solution value for all the instances in our extensive test bed. [ABSTRACT FROM AUTHOR]

Device-free localization (DFL) methods use measured changes in the received signal strength (RSS) between many pairs of RF nodes to provide location estimates of a person inside the wireless network. Fundamental challenges for RSS DFL methods include having a model of RSS measurements as a function of a person's location, and maintaining an accurate model as the environment changes over time. Current methods rely on either labeled empty-area calibration or labeled fingerprints with a person at each location. Both need to be frequently recalibrated or retrained to stay current with changing environments. Other DFL methods only localize people in motion. In this paper, we address these challenges by, first, introducing a new mixture model for link RSS as a function of a person's location, and second, providing the framework to update model parameters without ever being provided labeled data from either empty-area or known-location classes. We develop two new Bayesian localization methods based on our mixture model and experimentally validate our system at three test sites with seven days of measurements. We demonstrate that our methods localize a person with non-degrading performance in changing environments, and, in addition, reduce localization error by $\mathbf {11-51}$ 11 - 51 percent compared to other DFL methods. [ABSTRACT FROM AUTHOR]