Core Network Functions Research Articles

Satellite communications integration with terrestrial networks

In this paper we evaluate the feasibility of seamless and efficient integration of terrestrial communication systems with satellite networks. This aspect is considered by standardisation bodies such as ETSI [1], 5G-PPP [2] and 3GPP [3]. A comprehensive system is designed and implemented in an emulation prototype, including standard 3GPP LTE core network functionality [4] with its different layers: networking, data forwarding, control, management and monitoring and is validated through performance measurements. This work is a technical feasibility study of extending terrestrial communication systems with satellite networks as backhaul, increasing the energy efficiency, network robustness during natural disasters as well as being an alternative for peak-time data forwarding of the terrestrial communication services. Due to its global coverage property, terrestrial-satellite integration provides an obvious extension of communication services towards isolated and remote areas and an alternative for rural or highly distributed/highly mobile enterprise networks.

Agile Management and Interoperability Testing of SDN/NFV-Enriched 5G Core Networks

In the fifth generation (5G) era, the radio internet protocol capacity is expected to reach 20Gb/s per sector, and ultralarge content traffic will travel across a faster wireless/wireline access network and packet core network. Moreover, the massive and mission-critical Internet of Things is the main differentiator of 5G services. These types of real-time and large-bandwidth-consuming services require a radio latency of less than 1 ms and an end-to-end latency of less than a few milliseconds. By distributing 5G core nodes closer to cell sites, the backhaul traffic volume and latency can be significantly reduced by having mobile devices download content immediately from a closer content server. In this paper, we propose a novel solution based on software-defined network and network function virtualization technologies in order to achieve agile management of 5G core network functionalities with a proof-of-concept implementation targeted for the PyeongChang Winter Olympics and describe the results of interoperability testing experiences between two core networks.

Reactive security for SDN/NFV‐enabled industrial networks leveraging service function chaining

AbstractThe innovative application of fifth‐generation core technologies, ie, software‐defined networking (SDN) and network function virtualization, can help reduce capital and operational expenditures in industrial networks. Nevertheless, SDN expands the attack surface of the communication infrastructure, thus necessitating the introduction of additional security mechanisms. These major changes could not leave the industrial environment unaffected, with smart industrial deployments gradually becoming a reality, a trend that is often referred to as the Fourth Industrial Revolution or Industry 4.0. A wind park is a good example of an industrial application relying on a network with strict performance, security, and reliability requirements and was chosen as a representative example of industrial systems. This work highlights the benefit of leveraging the flexibility of SDN/network function virtualization–enabled networks to deploy enhanced reactive security mechanisms for the protection of the industrial network via the use of service function chaining. Moreover, the implementation of a proof‐of‐concept reactive security framework for an industrial‐grade wind park network is presented, along with a performance evaluation of the proposed approach. The framework is equipped with SDN and supervisory control and data acquisition honeypots, modeled on and deployable to the wind park, allowing continuous monitoring of the industrial network and detailed analysis of potential attacks, thus isolating attackers and enabling the assessment of their level of sophistication. Moreover, the applicability of the proposed solutions is assessed in the context of the specific industrial application based on the analysis of the network characteristics and requirements of an actual operating wind park.

SOCIAL NETWORKS AND COGNITIVE PERFORMANCE IN OLDER ADULTS WITH NORMAL COGNITION, MILD COGNITIVE IMPAIRMENT, AND MILD ALZHEIMER’S DISEASE

An emerging area of research points to an inverse association between social integration and risk for dementia. However, social integration measures in this literature are limited. The current study uses an egocentric network design wherein detailed data are collected on the specific individuals to whom subjects are connected, and on ties between them. The Social Networks in AD (SNAD) protocol was designed to examine associations between social network dynamics (size, density, composition, strength, supportiveness) and disease-associated factors. We administered SNAD to 82 cognitively normal (CN), 23 mild cognitive impairment (MCI), and 16 Alzheimer's disease (AD) subjects from the Indiana Alzheimer's Disease Center. Bivariate statistics were used to identify significant associations. Network characteristics varied significantly across diagnostic groups (df=2; Table 1 and Figure 1). CN individuals reported networks that were larger (p<.05) and less densely-connected (p<.01) than those with MCI or AD, and networks that contained affectively weaker ties (p<.01) and proportionally more friends versus kin (p<.05). Moreover, correlations revealed positive associations of global cognitive performance (MoCA) with network size (r=0.31; p<.001) and with proportion of friends (r=0.23; p<.001). MoCA performance was negatively correlated with network density (r=-0.23; p<.01) and mean tie strength (r=-0.30; p<.001). We observed similar patterns in all cognitive domains except visuospatial. Verbal memory (Craft Story Delayed Recall) was associated with larger (r=0.27; p<.01), less dense (r=-0.20; p<.05), and weaker networks (r=-0.21; p<.05). Executive function (Trail Making Test B) was more impaired in those with smaller networks (r=0.24; p<.01). Finally, subjects with larger networks (r=0.20; p<.05) composed of weaker ties (r=-0.22; p<.05) performed better on an attention task (Digit Span Test). We found more homogenous, insular, and kin-centered networks in MCI and AD relative to CN. Access to social resources through networks may create conditions that are protective of cognitive decline. Alternatively, our data may support a social contraction mechanism, wherein weaker ties to non-kin decay in the context of cognitive decline. Typical core network structure, function*, and composition by clinical cognitive status. *Note: Strength of tie denoted by thickness of black circle.

Performance Analysis of Network-Assisted D2D Discovery in Random Spatial Networks

Device-to-device (D2D) discovery is the inextricable prelude for the direct exchange of local traffic between cellular users in proximity. The D2D discovery process can be based on either autonomous actions taken by D2D-enabled devices, also known as network-assisted D2D discovery or core network functionalities to estimate proximity, also known as network-assisted D2D discovery. A key advantage of network-assisted D2D discovery is its potential to reduce the energy, signaling, and interference required for D2D discovery, by exploiting knowledge of the network layout. We analyze the performance of network-assisted D2D discovery in random spatial networks and derive useful guidelines for its design. We derive approximate expressions for the distance distribution between two D2D peers conditioned on the core network’s knowledge of the cellular network layout, assuming that the base stations are distributed according to the Poisson point process. The expressions are used to assess the interplay between the D2D discovery probability and key system parameters, such as network intensity and transmit power, as well as to identify conditions to maximize the D2D discovery probability. Numerical results validate the accuracy of our findings and provide insights on the performance tradeoffs of network-assisted D2D discovery.

New Paradigm of 5G Wireless Internet

5G network is anticipated to meet the challenging requirements of mobile traffic in the 2020’s, which are characterized by super high data rate, low latency, high mobility, high energy efficiency, and high traffic density. This paper provides an overview of China Mobile’s 5G vision and potential solutions. Targeting a paradigm shift to user-centric network operation from the traditional cell-centric operation, 5G radio access network (RAN) design considerations are presented, including RAN restructure, Turbo charged edge, core network (CN) and RAN function repartition, and network slice as a service. Adaptive multiple connections in the user-centric operation is further investigated, where the decoupled downlink and uplink, decoupled control and data, and adaptive multiple connections provide sufficient means to achieve a 5G network with “no more cells.” Software-defined air interface (SDAI) is presented under a unified framework, in which the frame structure, waveform, multiple access, duplex mode, and antenna configuration can be adaptively configured. New paradigm of 5G network featuring user-centric network (UCN) and SDAI is needed to meet the diverse yet extremely stringent requirements across the broad scope of 5G scenarios.

Cost analysis of initial deployment strategies for virtualized mobile core network functions

A virtualized network infrastructure is composed of multiple virtualized network functions (VNF) interconnected by well defined interfaces, and thus forming a VNF-graph. The initial deployment of such a VNF-graph inside a data center (DC) is a complex task with multidimensional aspects compared to deploying a single VNF that may represent a single network function. The problem space becomes more complex when each VNF is further decomposed into multiple VNF components (VNFC), where each VNFC embodies a subset of network functions attributed to the respective VNF. The challenge is to ensure that the deployment strategy meets the intra-functional constraints between the multiple VNFCs constituting the VNF-graph while ensuring service, performance and operational integrity, and also ensures optimal utilization of the underlying resources of the DC infrastructure (DCI). In this article we analyze the cost incurred by two “constraint-based heuristically applied” initial VNF/VNFC deployment strategies with reference to a virtualized mobile network infrastructure providing EPCaaS (evolved packet core as a service) while taking into consideration functional and administrative constraints. The cost of deployment is measured in terms of the utilization of DC infrastructure resources such as compute and networking. We also present the discussion in view of the ETSI NFV MANO framework, undergoing standardization, that is responsible for management and orchestration of NFV systems including VNF deployment.

Xhaul: toward an integrated fronthaul/backhaul architecture in 5G networks

The Xhaul architecture presented in this article is aimed at developing a 5G integrated backhaul and fronthaul transport network enabling flexible and software-defined reconfiguration of all networking elements in a multi-tenant and service-oriented unified management environment. The Xhaul transport network vision consists of high-capacity switches and heterogeneous transmission links (e.g., fiber or wireless optics, high-capacity copper, mmWave) interconnecting remote radio heads, 5G points of attachment (5GPoAs, e.g., macro- and small cells), centralized- processing units (mini data centers), and points of presence of the core networks of one or multiple service provider(s). This transport network shall flexibly interconnect distributed 5G radio access and core network functions, hosted on network centralized nodes, through the implementation of a control infrastructure using a unified, abstract network model for control plane integration (Xhaul Control Infrastructure, XCI); and a unified data plane encompassing innovative high-capacity transmission technologies and novel deterministic-latency switch architectures (Xhaul packet Forwarding Element, XFE). Standardization is expected to play a major role in a future 5G integrated front haul/backhaul architecture for multi-vendor interoperability reasons. To this end, we review the major relevant activities in the current standardization landscape and the potential impact on the Xhaul architecture.

Optical service chaining for network function virtualization

This article presents an efficient optical service chaining architecture for network function virtualization in data centers. Service chaining (i.e., steering traffic through a sequence of network functions) is one emerging application of software-defined networking. However, existing schemes steer traffic solely in the packet domain, which is well suited for fine-grained (e.g., peruser level) flows carrying a relatively small volume of traffic. This article discusses how packet-based schemes do not yield sufficient efficiency for large/aggregated flows steered through high-capacity core network functions. It introduces an optical steering domain into the operator's data centers for NFV service chaining at a coarse-grained traffic level using wavelength switching. Performance evaluation shows that the optical steering domain can achieve significant power savings compared to using packet technologies as flow rates and the number of vNFs per service chain grow.

A survey on congestion control for delay and disruption tolerant networks

Delay and disruption tolerant networks (DTNs) may experience frequent and long-lived connectivity disruptions. Unlike traditional networks, such as the TCP/IP-based Internet, DTNs are often subject to high latency caused by very long propagation delays (e.g., interplanetary communication) and/or intermittent connectivity. Another feature that sets DTNs apart from conventional networks is that there is no guarantee of end-to-end connectivity between source and destination. Such distinct features pose a number of technical challenges in designing core network functions such as routing and congestion control. In this paper, we survey the state-of-the-art in DTN congestion control. We propose a taxonomy to map the DTN congestion control design space and use it to classify existing DTN congestion control mechanisms.

Accelerating Application Identification with Two-Stage Matching and Pre-Classification

Modern datacenter and enterprise networks require application identification to enable granular traffic control that either improves data transfer rates or ensures network security. Providing application visibility as a core network function is challenging due to its performance requirements, including high throughput, low memory usage, and high identification accuracy. This paper presents a payload-based application identification method using a signature matching engine utilizing characteristics of the application identification. The solution uses two-stage matching and pre-classification to simultaneously improve the throughput and reduce the memory. Compared to a state-of-the-art common regular expression engine, this matching engine achieves 38% memory use reduction and triples the throughput. In addition, the solution is orthogonal to most existing optimization techniques for regular expression matching, which means it can be leveraged to further increase the performance of other matching algorithms.

Routing, security, resource management, and monitoring in ad hoc networks: Implementation and integration

In this paper we present the implementation and integration of core network functions, including routing, security, resource management, and network monitoring that are critical to the efficient operation of a mobile ad hoc network (MANET). The integration of the aforementioned functionalities enables them to support one another, forming a cohesive system. We design and implement a new ad hoc routing protocol that can relay connectivity, link quality, or any other information that is globally available to the underlying routing mechanism and use such information to improve routing decisions. Our implementation of resource management and topology control utilizes the connectivity information from the routing protocol to derive topologies that consume less energy and cause less interference. Our key management solution supports IPsec deployment and establishes secure paths enabling secure information propagation for routing and topology control messages, as well as for application data. Moreover, it provides an integrated trust component that can guide trust decisions among nodes in a network. To debug and monitor these core functionalities we implement both centralized and decentralized network monitoring solutions, which in turn extract and display information, such as connectivity and secure tunnels, from our security, routing, and topology control solutions. Routing, security, and monitoring mechanisms support concurrent use of IPv6 and IPv4 addresses. We briefly describe each component of the solution and discuss the integration of these components into a unified system to support mobile nodes. We describe experiments conducted on a wireless ad hoc network testbed and thus illustrate the interaction between the various technologies. Concluding, we discuss lessons learned and how we make available our implementations to enable further experimentation by the wireless network research community.

On Bandwidth Tiered Service

Many network operators offer some type of tiered service, in which users may select only from a small set of service levels (tiers). Such a service has the potential to simplify a wide range of core network functions, allowing the providers to scale their operations efficiently. In this work, we study a number of problem variants related to service tier selection. Our contributions include: (1) a faster algorithm for obtaining optimal service tiers; (2) a new formulation and optimal algorithm to optimize jointly the number and magnitude of each service tier; and (3) the concept of ??TDM emulation?? in which all service tiers are multiples of the same (software-configurable) bandwidth unit, and a suite of algorithms to select jointly the basic unit and service tiers. Our work provides a systematic framework for reasoning about and tackling algorithmically the general problem of service tier selection, and has applications to a number of networking contexts, including access networks (e.g., determining the tiers for ADSL, cable modem networks or PONs) and core networks (e.g., LSP sizing for MPLS networks).

S-WiMAX: adaptation of IEEE 802.16e for mobile satellite services

Mobile satellite services are attracting renewed attention stemming from the FCC ancillary terrestrial component ruling that allows satellite spectrum to be used for integrated terrestrial services in the footprint of the satellite. This attention is focused on the development of dual-mode satellite-terrestrial devices to facilitate hybrid satellite-terrestrial networks intended by the ATC order. The satellite component in these dual-mode devices is best adapted from the air interface chosen for the ATC to optimize form factor, especially for small hand-held devices, mobility management, power efficiency, and a common core network functionality. With the advent of WiMAX as a viable 4G technology, satellite adaptation of WiMAX has been considered for the satellite services coupled with WiMAX ATC. The main considerations for satellite adaptation of WiMAX, relative to its terrestrial counterpart, are reduced link margin and longer transmission delays - both absolute delay from the center of a spot beam to the satellite and differential delay between the beam edge and the beam center to the satellite. These considerations suggest adaptation of the sub-channelization schemes, the frame synchronization methods, and the ranging process in WiMAX to make it operable over satellite, while keeping the general framework of the WiMAX protocol stack intact, thereby facilitating the incorporation of S-WiMAX into a common baseband processor with terrestrial WiMAX; this allows S-WiMAX to be added to terrestrial WiMAX devices with minimal cost and form-factor impact. Methods for these adaptations are considered here.

Research activities on UMTS radio interface, network architectures, and planning

Currently worldwide activities are going on to define third-generation mobile radio systems (IMT-2000 on ITU/UMTS in Europe). These systems aim to support a wide range of services from voice and low-rate data up to high-rate data services, including multimedia services, and circuit- and packet-oriented services. These systems will operate in all radio environments to provide service to anyone, anytime, anywhere. In Europe the European Commission is partly funding research activities in the ACTS framework related to third-generation systems. A spectrum-efficient multiple access scheme proposal is being developed by the ACTS FRAMES project to fulfill the requirements for terrestrial third-generation mobile radio systems. The results and proposals of FRAMES are used as input mainly to the ETSI standardization process. This radio access scheme addresses the different worldwide standardization activities where TDMA and CDMA-based solutions are currently expected. Different proposals for the UMTS system architecture and network issues are currently being discussed in the relevant standardization bodies. On one hand, the GRAN approach envisages a single UMTS access part able to connect with multiple core networks; on the other hand, the generic core network approach proposes to develop UMTS core network functionality able to handle multiple access networks, which can adopt different types of radio access techniques. The ACTS RAINBOW project presents a proposal where both approaches are unified in a system structure. From the network planning viewpoint, the major features of a third-generation mobile system are the wide variety of services provided, the high number of customers expected (especially in urban and densely populated areas), the network architecture flexibility to allow different configurations to be deployed, and the advanced mobility management strategies. From this perspective the ACTS STORMS project is elaborating new planning methodologies tailored to the specific needs of a UMTS operator, and designing and developing a set of software modules covering the whole set of disciplines involved in mobile network planning.

Intelligent network requirements for personal communications services

It is shown that a moderate set of capabilities within the service switching point (SSP), service control point (SCP), and intelligent peripheral (IP), which are the intelligent network (IN) components directly responsible for the real-time execution and control of end-user services, can engender a wide range of end-user personal communication service (PCS) features. These capabilities could be used as the starting point for an economic analysis of IN implementation costs versus service worth. From a very large target set of call model trigger check points (TCPs), the dozen or so identified in the CCITT Capability Set 1 are shown to be sufficient. The SCP and IP functional entity actions identified are also sufficient to support PCS core network functions.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>