Transport Network Resources Research Articles

Intelligent Traffic Engineering for 6G Heterogeneous Transport Networks

Novel architectures incorporating transport networks and artificial intelligence (AI) are currently being developed for beyond 5G and 6G technologies. Given that the interfacing mobile and transport network nodes deliver high transactional packet volume in downlink and uplink streams, 6G networks envision adopting diverse transport networks, including non-terrestrial types of transport networks such as the satellite network, High-Altitude Platform Systems (HAPS), and DOCSIS cable TV. Hence, there is a need to match the traffic to the transport network. This paper focuses on such a matching problem and defines a method that leverages machine learning and mixed-integer linear programming. Consequently, the proposed scheme in this paper is to develop a traffic steering capability based on types of transport networks, namely, optical, satellite, and DOCSIS cable. Novel findings demonstrate a more than 90% accuracy of steered traffic to respective types of transport networks for dedicated transport network resources.

A Study on Two-stage Selection Model of Tourism Destination at the Scale of Urban Agglomerations

Considering that the demand of tourism destination is variable on the scale of urban agglomeration, the selection process of travel destination is divided into two stages. The traditional transportation combination model based on the multinomial Logit cannot reflect this characteristic. And it is the lack of consideration of the influence of travel distribution and the dynamic transfer of passenger flow between various transport routes. Therefore, this thesis established a combination model of travel demand distribution and transportation assignment with two-stage terminal selection characteristics based on the nested Logit. Based on the analysis of tourists' trip process on the scale of urban agglomeration, a tourist flow transport network with travel destination nest structure is constructed. The generalized cost impedance function of transportation route is constructed based on the direct cost of transportation mode and the indirect cost of travel time. Based on the characteristics of two-stage destination selection of tourists, the form of travel distribution function of tourist flow is given. Through the first-order optimization conditions, it proved that the volume of travel distribution and tourism passenger transport assignment can meet the two-stage equilibrium conditions in the equilibrium state. Based on the idea of MSA algorithm, it designed the solution algorithm of the model and verified the feasibility of the model and algorithm in a simplified example. The calculation results show that the two-stage equilibrium assignment model proposed in this paper can obtain the volume of travel distribution and transportation assignment at the same time, meanwhile compared with the multinomial logit model, the nested Logit structure fully considers the attraction measure of the city destination and the scenic spot destination, which is more in line with the choice behavior of the tourists when choosing the transportation route. Thus, it provides a new comparable method for the optimal allocation of tourism passenger flow transport network resources on the scale of urban agglomeration, and can provide data support for the transportation organization plans of government decision-making departments and tourism transport enterprises.

A novel bi-level programming model for structure sustainability optimization of passenger transport corridor

The transportation industry has entered a new stage from quantity expanding to structure optimization, quality and efficiency improvement, and from respective governance to integrative development. This indicates that the traditional corridor mode allocation dominated by quantity equilibrium can no longer meet the requirements of the new stage. In this paper, we propose a multi-entity programming model based on the economic equilibrium between supply and demand. It not only ensures the economic equilibrium in the market, but also maximizes the social benefits of the whole system, thereby realizing the sustainable development of the transportation system. Also, the Globalsearch algorithm and intlinprog algorithm are designed to solve the problem. The actual case of Beijing-Shanghai corridor shows that the model and algorithms are effective, providing decision support for the optimal allocation of regional transport network resources.

Optimizing Bus Line Based on Metro-Bus Integration

Metros are usually built and added on the basis of a completed bus network in Chinese cities. After the metro construction, it is faced with the problem of how to adjust and optimize the original bus lines based on the new metro system. This research mainly proposes a bus line optimization method based on bus and metro integration. In the consideration of the geographical space, the cooperation and competition relationship between bus and metro lines is qualitatively introduced according to the geographical location and service range of metro (800 m radius) and bus (500 m radius) stations. The competition and cooperation indexes are applied to define the co-opetition relationship between bus and metro lines. The bus line optimization model is constructed based on the co-opetition coefficient and Changsha Metro Line Number 2 is chosen as a case study to verify the optimization model. The results show that the positive competition, efficient cooperation, and travel efficiency between metro and bus has been significantly enhanced after optimization. Moreover, this paper provides a reasonable reference for public transport network planning and resource allocation.

Open-Source Network Optimization Software in the Open SDN/NFV Transport Ecosystem

Transport ecosystems that combine software defined networking (SDN) and network function virtualization (NFV) are characterized by an unprecedented network control and resource dynamicity. Manual optimization is unmanageable. In this context, open systems that manage and orchestrate SDN/NFV-enabled networks offer programming frameworks that abstract the low-level particularities in the data-plane forwarding devices and in the hardware appliances that provide the IT resources. Although these open systems present notable complexity, their programming abstractions promote a client layer where third-party applications can provide different functionalities thus enabling optimization-as-a-service business opportunities. In this paper, we cover open-source optimization software initiatives for offline planning and online provisioning and orchestration of SDN/NFV networks. With this goal in mind, we first focus on open software (and framework) initiatives through a set of realistic use cases that require optimization in multi-layer optical transport scenarios and ecosystems that combine transport with IT resources. The importance of a joint optimization of both network and IT domains is emphasized, a new paradigm triggered by SDN/NFV technologies. We discuss the theoretical limits to algorithm performances, and review available open-source frameworks for problem modeling that enable the interaction with solvers. Finally, we focus on the Net2Plan open-source network planning tool, a Java-based software that suitably embraces the multiple features required in the optimization of joint transport network and IT resource SDN/NFV ecosystems. Recent works based on Net2Plan are reviewed to illustrate its suitability for rapid algorithm prototyping, and for interaction with SDN/NFV-enabled networks.

Orchestration of End-to-End Network Services in the 5G-Crosshaul Multi-Domain Multi-Technology Transport Network

Upcoming 5G mobile networks are addressing ambitious KPIs not just in terms of capacity and latency, but also in terms of network control and management. In this direction, network management schemes need to evolve to provide the required flexibility, and automated and integrated management of 5G networks. This also applies to the 5G-Crosshaul transport network, which provides an integrated fronthaul and backhaul. Software defined networking and NFV are seen as key enablers for that. This article validates the flexibility, scalability, and recovery capabilities of the 5G-Crosshaul architecture in a testbed distributed geographically. More specifically, the central component of the validation is the hierarchical 5G-XCI, conceived to handle multi-domain multi-technology transport network resources. Its performance is characterized through two experimental case studies. The first one illustrates the automated provisioning of all network resources required to deploy a complete LTE virtual mobile network featuring fronthaul and backhaul configurations. This takes 10.467 s on average for the network under test. The second one exploits the flexibility of the hierarchical XCI to apply local or centralized service recovery in the event of link failure depending on the desired path optimality vs. recovery time trade-off. On average, recovery takes 0.299 s and 6.652 s, respectively. Overall, the proposed solution contributes to attaining the target set for 5G networks of reducing service setup from hours to minutes.

5G-Crosshaul Network Slicing: Enabling Multi-Tenancy in Mobile Transport Networks

5G requires a redesign of transport networks in order to feed the increasingly bandwidth hungry radio access networks and to benefit from the performance/cost efficiency provided by the integration of both backhaul and fronthaul segments over the same transport substrate as well as the incorporation of cloud RAN architectures. In addition, to increase its usage and cost efficiency, this new transport network should allow simultaneous use by different tenants (e.g. MVNOs, OTTs, and vertical industries). This article presents the 5G transport network architecture designed in the 5G-Crosshaul project to address this challenge. An SDN/NFV-based control plane has been designed that enables multi-tenancy through network slicing. The proposed solution allows for flexible and efficient allocation of transport network resources (networking and computing) to multiple tenants by leveraging on widespread architectural frameworks for NFV (ETSI NFV) and SDN (e.g., Open Daylight and ONOS).

Orchestration of RAN and Transport Networks for 5G: An SDN Approach

The fifth generation of mobile networks is planned to be commercially available in a few years. The scope of 5G goes beyond introducing new radio interfaces, and will include new services like low-latency industrial applications, as well as new deployment models such as cooperative cells and densification through small cells. An efficient realization of these new features greatly benefit from tight coordination among radio and transport network resources, something that is missing in current networks. In this article, we first present an overview of the benefits and technical requirements of resource coordination across radio and transport networks in the context of 5G. Then, we discuss how SDN principles can bring programmability to both the transport and radio domains, which in turn enables the design of a hierarchical, modular, and programmable control and orchestration plane across the domains. Finally, we introduce two use cases of SDN-based transport and RAN orchestration, and present an experimental implementation of them in a testbed in our lab, which confirms the feasibility and benefits of the proposed orchestration.

Formation of service and resource stability conditions of urban public passenger transport

Service and resource parameters of urban public passenger transport operation are dominant for formation of its sustainability from the standpoint of internal and external processes. The sustainability of urban public passenger transport reflects its properties to keep under the influence of internal and external influences for a long time, which is correlated with time and changing the system, processes of its homeostatic equilibrium state, structure, nature of operation and to ensure the effective functioning of the urban environment. Its sustainability is achieved by forming reaction responses to influence, which aims to compensate their negative impact. The source of the formation of such compensatory actions is reserves of its internal (transport resources) and external resources (transport network resources). Formation of compensatory actions to influence must provide the appropriate level of its operation results of urban public passenger transport. Synthesis of the requirement to provide compensation of resource needs and performance characteristics helps to define the conditions for achieving sustainability of functional processes of urban public passenger transport.The form of the boundaries of acceptable sustainability parameters of urban public passenger transport is revealed from the standpoint of service and resource characteristics of its operation. The sustainability scheme of functional processes of urban public passenger transport is reflected conditions and principles of sustainable development of urban environments and allows to assess sustainability degree using an available form of their accounting.

Demonstration of Dynamic Resource Sharing Benefits in an Optical C-RAN

The next generation of mobile communication (i.e., 5G) will bring new challenges for the transport infrastructure, e.g., in terms of flexibility and capacity. The joint orchestration of radio and transport resources can help to address some of these challenges. One example is the possibility of reconfiguring the use of the transport network resources according to the spatial and temporal variations of the wireless traffic patterns. Using the concept of dynamic resource sharing, a limited pool of transport resources can be shared among a large number of radio base stations (RBSs), thus reducing considerably the overall deployment cost of the transport infrastructure. This paper proposes a provisioning strategy for a centralized radio access network with an optical transport whose wavelength resources can be dynamically shared among multiple RBSs. The proposed strategy utilizes a hierarchical software-defined networking control plane where a global orchestrator optimizes the usage of radio and transport resources. The benefits of the proposed strategy are assessed both by simulation and by experiment via an optical data plane emulator developed for this purpose. It is shown that the dynamic resource sharing can save up to 31.4% of transport resources compared to a conventional dimensioning approach, i.e., based on the overprovi-sioning of wavelength resources.

CSO: cross stratum optimization for optical as a service

Data center interconnection with elastic optical networks is a promising scenario to meet the high burstiness and high-bandwidth requirements of services. Many data center services require lower delay and higher availability with end-to-end guaranteed QoS, which involves both application and transport network resources. However, in the current mode of operation, the control of elastic optical networks and data centers is separately deployed. Enabling even limited interworking among these separated control systems requires the adoption of complex and inelastic interfaces among the various networks, and this solution is not efficient enough to provide the required QoS. In this article, we present a novel cross stratum optimization (CSO) architecture in elastic data center optical interconnection. The proposed architecture can allow global optimization and control across elastic optical transport network and data center application stratum heterogeneous resources to meet the QoS requirement with the objective of optical as a service (OaaS). The functional modules of CSO architecture, including the core elements of application and transport controllers, are described in detail. The cooperation procedure in CSO-based service provisioning and cross stratum service resilience modes is investigated. The overall feasibility and efficiency of the proposed architecture is also experimentally demonstrated on our OaaS testbed with four OpenFlow-enabled elastic optical nodes, and compared to MFA, ALB, and CSO-DGLB service provisioning schemes in terms of path setup/release/adjustment latency, blocking probability, and resource occupation rate. Numerical results are given and analyzed based on the testbed. Some future discussion and exploration issues are presented in the conclusion.

First field demonstration of cloud datacenter workflow automation employing dynamic optical transport network resources under OpenStack and OpenFlow orchestration

For the first time, we demonstrate the orchestration of elastic datacenter and inter-datacenter transport network resources using a combination of OpenStack and OpenFlow. Programmatic control allows a datacenter operator to dynamically request optical lightpaths from a transport network operator to accommodate rapid changes of inter-datacenter workflows.

Software defined networking opportunities for transport

The economic landscape where trends of computing and networking are diverging creates motivation for new engineering paradigms. One emerging paradigm is software defined networking, whose attributes include separation of control from forwarding, enabling joint optimization of computing and networking deployments, software-defined functions at a number of layers, including the transport (i.e., optical and TDM) layer, enabling simpler interworking of different administrative and technology domains, and application-aware transport network resources. This column provides some background on the aspects of SDN related to transport networking, summarizes major drivers, trends, and issues to be addressed, and concludes by discussing areas of potential research and development for transport-related future SDN work.

Compressed Transport of Baseband Signals in Radio Access Networks

In current wireless base station solutions it is becoming common to physically separate baseband units and radio subsystems. In many wireless technologies this architecture requires allocation of significant transport network resources. In this paper a low-latency baseband signal compression scheme is presented. The compression scheme significantly lowers the transport data rate while maintaining low levels of signal distortion, thus resulting in a lower-cost transport network. Considering the importance of packet-based networks, a number of additional novel compression schemes are proposed. They are optimized for transport networks that implement a quality-of-service (QoS) mechanism and/or multi-link transmission. The compression schemes are parameterized such that a smooth trade-off between the required signal quality and compression performance can be achieved through operator choice of the suitable parameter values. An attractive feature of these schemes is that they can be applied to different wireless technologies, with appropriate parameter settings, without disrupting the present architecture. The proposed solutions will lead to a cost-effective implementation of collocated and distributed network-centric baseband processing, coordinated multi-point (CoMP) and/or distributed antenna system (DAS) which are critical topics for the entire wireless telecommunications industry and infrastructure.

A novel approach to counter denial of service attacks against transport network resources

A new generation of optical transport networks (OTNs) and wavelength division multiplexing (WDM) networks is currently emerging. Their control plane for fast transport path creation, protection, and restoration is inevitable for cost effectiveness. Such automatically switched optical networks (ASONs) are susceptible to denial of service (DoS) attacks at their user network interface (UNI) and external network node interface (E-NNI) access points. Attacks against transport resources aim to prevent users from setting up transport connections, such as paths in OTNs or wavelengths in WDM networks. We present novel concepts for detecting such attacks and identifying the attackers, covering both 'simple' and distributed DoS (DDoS) attacks. We have analyzed a variety of potential attack scenarios by means of simulation to validate the detection methods and the framework for effectiveness. Our results indicate that the framework exhibits good detection rates for the DDoS attacks mentioned earlier. After discussing the problem and methods chosen to address it, we explain the results of our analysis.

Admission control and resource reservation for session-based applications in next generation networks

Today's telecommunications networks are moving towards full convergence of voice and data services as well as seamless access via mobile and fixed networks. This implies a transformation of the underlying transport network technology (moving towards IP) as well as the way that transport resources can be shared across multiple applications and controlled from the intelligence domain. This paper provides an overview of admission control and resource reservation concepts and techniques for session-based applications to drive transport network resources. It also provides a brief description of the connectivity resources architecture being developed in BT, as well as the different functional architectures being proposed by the main standards bodies and industry organisations working in this area.

Virtual network resource management for next-generation networks

The multilayer structure of transport networks presents a key challenge in network resource management. In this article we present a virtual network approach to the management of transport network resources. We describe the approach as developed for the management of large-scale ATM networks and discuss the application to the next generation of multilayer transport networks.

Connectability: a performance metric for reconfigurable transport networks

This paper presents a metric for managing dynamically reconfigurable transport networks. In such networks, one physical set of transport links can be configured into many different logical networks, in order to meet uncertain and volatile traffic demands. Connectability is a figure of merit for capturing the composite routing efficiency and capacity utilization of a transport network. Connectability is mathematically inspired by existing metrics for reliability. Reliability concepts are adapted to quantify notions of efficiency in reconfigurable networks. The authors define connectability mathematically, and set out a procedure for its' calculation in a distributed real-time setting. The centralized version of this calculation has O(n log n) time complexity. A series of simulation studies are presented to illustrate the use of connectability in characterizing strategies for transport network reconfiguration. One strategy based on the isolated calculation of connectability at each node is shown to yield lower blocking and more efficient use of transport network resources than the other strategies tested. Finally, a short study of applying connectability to restoration in a national network demonstrates that there is a continuum along which restoration can be temporarily traded off against transport network management.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Abstraction and control of transport network resources for intelligent networks

AbstractThe intelligent network (IN) is expected to play an important role in rapidly and efficiently introducing new telecommunication services. This, paper discusses the abstraction and control methods for constructing a service control environment in the intelligent network which does not depend on specific service. By using this method, a real network configuration is abstracted into several patterns, considering the control points required by each service specification and each pattern can be described as a combination of functional virtualized resources.It is made possible to handle the diversified service specifications in a unified way which is independent of detailed conditions of the transport network. It is made possible also to ensure the service independency of the control interface specifying the interface by control of each virtualized resources. Moreover, a model for the call control is proposed and the function assignment in introducing IN into existing network is discussed.

Broadband Traffic Forecasting in the Transport Network

This paper proposes a modification of traffic forecast model generated by residential and small business (SOHO, Small Office Home Office) users. The model includes forecasted values of different relevant factors and competition on broadband market. It allows forecasting the number of users for various broadband technologies and interaction impact of long-standing technologies as well as the impact of the new technology entrant on the market. All the necessary parameters are evaluated for the Serbian broadband market. The long-term forecasted results of broadband traffic are given. The analyses and evaluations performed are important inputs for the transport network resources planning.