Next-generation Network Architecture Research Articles

Automated and Massive-scale CCNx Experiments with Software-Defined SmartX Boxes

Experimental research in Content-Centric Networking (CCN) is important to the evaluation of large-scale information centric multimedia services for next-generation network architecture. This paper presents a new experiment support tool over software-defined SmartX Boxes that enables the automated and massive-scale experimental validations of devised CCN model and service prototypes, which aims to fill-in the existing gap between real and simulated (including emulated) experiments.

Incentive mechanisms for user-provided networks

The increasing mobile data demand and the proliferation of advanced handheld devices place user-provided networks in a conspicuous position for next-generation network architectures. There has been growing consensus that user-provided networks can play a crucial role in both self-organizing and operator-controlled wireless networks, as they enable the exploitation of the diverse communication needs and resources of different users. However, in user-provided networks both the availability of and demand for Internet access depend on mobile devices; therefore, the success of such networks relies on active user participation. In this article, we analyze the design challenges of incentive mechanisms for encouraging user engagement in user-provided networks. Motivated by recently launched business models, we focus on mobile user-provided networks where the energy consumption and data usage costs are critical and have a large impact on users' decisions on both requesting and offering user-provided network services. We outline two novel incentive schemes that have been proposed for such user-provided networks, and discuss the open issues that must be further addressed.

Energy-Efficient Baseband Unit Placement in a Fixed/Mobile Converged WDM Aggregation Network

Energy efficiency is expected to be a key design parameter for next-generation access/aggregation networks. Using a single network infrastructure to aggregate/backhaul both mobile and fixed network traffic, typically referred to as fixed/mobile convergence (FMC), seems a promising strategy to pursue energy efficiency. WDM networks are a prominent candidate to support next-generation FMC network architectures, as they provide huge capacity at relatively low costs and energy consumption. We consider a FMC WDM aggregation network in which the novel concept of “hotelling” of mobile baseband units (BBUs) is employed. The so-called BBU hotelling consists in separating BBUs from their cell sites and consolidating them in single locations, called hotels. As a result, the aggregation network will transport both IP (fixed and mobile) traffic and CPRI (fronthaul) traffic, the latter exchanged between each BBU and its cell site. In this paper, we propose an energy-efficient WDM aggregation network, and we formally define the BBU placement optimization problem, whose objective is to minimize the defined aggregation infrastructure power (AIP). We consider three different network architectures: Bypass, Opaque, and No-Hotel, which feature different placement of BBUs and routing of traffic. By modeling the power contributions of each active device, we study how and how much BBU consolidation, optical bypass, and active traffic aggregation influence the AIP, for all the three architectures. Our results show that, in our case study, the proposed architectures enable savings up to about 60%-65% in dense-urban/urban and about 40% in rural scenarios.

Traffic Model of IMS/NGN Architecture with Transport Stratum Based on MPLS Technology

Abstract Growing expectations for a fast access to information create strong demands for a universal telecommunication network architecture, which provides various services with strictly determined quality. Currently it is assumed that these requirements will be satisfied by Next Generation Network (NGN), which consists of two stratums and includes IP Multimedia Subsystem (IMS) elements. To guarantee Quality of Service (QoS) all NGN stratums have to be correctly designed and dimensioned. For this reason appropriate traffic models must be developed and applied, which should be efficient and simple enough for practical applications. In the paper such a traffic model of a single domain of NGN with transport stratum based on Multiprotocol Label Switching (MPLS) technology is presented. The model allows evaluation of mean transport stratum response time and can be useful for calculating time of processing requests in the entire NGN architecture. Results obtained using the presented model are described and discussed. As a result of the discussion, elementary relationships between network parameters and transport stratum response time are indicated.

Next-generation QoS control architectures for distribution smart grid communication networks

This article presents a proposal for applying the ITU-T end-to-end QoS control architecture for next-generation networks to the distribution smart grid communication networks. We propose the use of a QoS broker device to enhance the QoS in the smart grid electrical distribution access domains by providing a centralization of QoS management. Our proposal takes decisions based on current network data traffic flows, existing QoS policies and customer service level agreements and facilitates interoperability with other technology domains in order to achieve seamless end-to-end QoS. The key feature of this end-toend QoS control is the mapping of QoS parameters mainly between broadband power line and wireless technologies that principally serve the distribution smart grid but it can be applied to other communication technologies as well.

Service Control Layer (SCL): Enabling Rule-based Control and Enrichment in Next-Generation Telecom Service Delivery

Telecom operators have started to make significant investments towards evolving their Service Delivery Platforms (SDPs) to a next-generation architecture, based on IP technologies and standards such as Session Initiation Protocol (SIP), Service Oriented Architecture (SOA) and increasingly, Web 2.0. These investments are tightly coupled with demands for network middleware infrastructures that allow for rapid service creation and execution, efficient service orchestration and management, and flexible exposure of core network capabilities as services. A key service management functionality of integrated SDP is IP-based service control. Traditionally, service control functionalities have been vertically integrated with service logic and hence, are inflexible and costly to maintain and upgrade. IP Multimedia Subsystem (IMS), which defines the overlay service architecture for next generation networks, stopped short in designing a flexible service control component. In this paper, we present the design and implementation of a service control layer (SCL) for IMS networks, which is flexible on two fronts, viz., the SIP based service modeling for fine grained service control and the programmability of the controlling action implemented by external business services. We present the detailed description of the design and implementation of SCL followed by the results obtained from a performance evaluation exercise that evaluates the scalability of SCL.

Integrated optimization of aggregation and core for varying NGN architectures

The tremendous increase in network traffic compared to relatively constant per customer revenues forces network operators to change both their aggregation and core networks. The key questions in this context are how cost-effective carrier-grade Ethernet transport abilities, high-capacity WDM transport and scalable, high-capacity IP routers influence the structure and the architecture of next generation networks: What is the right size of an IP backbone? How should aggregation be organized? How (de-)? centralized should services like video-on-demand be provided and how (de-)? centralized should functionalities such as accounting be implemented? In this paper, we present a model-based optimization approach using mixed-integer programs at its core to answer these questions. We illustrate our general solution approach, describe the mathematical programming models used to solve the arising subproblems, and discuss how to express common network architecture variants within these models. Computational studies on nation-wide reference networks with more than 1800 locations, which have been developed within the German research project 100GET, show the effectiveness of our approach and its usefulness in evaluating alternative network architectures and network expansion strategies.

Performance Analysis of Dual-Priority Multilayer Multistage Interconnection Networks under Multicast Environment

Next-generation network architectures strive to achieve high bandwidth and ultralow latency for the packets traversing the offered end-to-end paths. Multistage Interconnection Networks (MINs) are often employed for implementing NGNs, but while MINs are fairly flexible in handling varieties of traffic loads, they tend to quickly saturate under broadcast and multicast traffic, especially at increasing size networks. As a response to this issue, multilayer MINs have been proposed, however their performance prediction and evaluation has not been studied sufficiently insofar. In this paper, we evaluate and discuss the performance of multilayer MINs under multicast traffic, considering also two levels of packet priorities, since support for multiple QoS levels is an indispensible requirement for NGNs. Different offered loads and buffer size configurations are examined in this context, and performance results are given for the two most important network performance factors, namely packet throughput and delay. We also introduce and calculate a universal performance fac­tor, which includes the importance aspect of each of the above main performance factors. The findings of this study can be used by NGN system designers in order to predict the performance of each configuration and adjust the design of their communication infrastructure to the traffic requirements at hand.

Inside View

Cooperative communication looks very promising as a next-generation wireless network architecture. Li Chen, Rolando Carrasco and Ian Wassell tell us why and how they are working to improve system performance.

Proposal of a Next Generation Network Architecture Based on Web Service Technologies

The IP Multimedia Subsystem (IMS) establishes a session between end terminals as a client/server application in the Next Generation Network (NGN). These days, many application services are being provided as Web services. In this letter, we propose a new NGN architecture conforming to the architectural styles of Representational State Transfer (REST), which is a Web service technology for solving interoperability and traffic concentration problems in the Session Initiation Protocol (SIP).

Extending next generation network (NGN) architecture for connection-oriented transport

Next Generation Network (NGN) is the architecture of the International Telecommunication Union-Telecommunication Standardization Sector (ITU-T in short) supporting the provisioning of Quality of Service (QoS)-guaranteed services over different packet transport technologies. Such capability derives from the effectiveness of a dynamic resource control performed by the Resource Admission Control Function (RACF) at service set-up. Control Plane (CP)-enabled connection-oriented transport networks can guarantee the QoS support for new bandwidth-greedy NGN services across the optical transport segment thanks to the ability of automatic path set-up and traffic segregation. But the Internet Engineering Task Force (IETF) standard for the CP in transport networks, i.e., the Generalized Multi-Protocol Label Switching (GMPLS) is not yet included within the NGN supported transport technologies. In this work, we outline architectural guidelines and design strategies for ITU-T RACF employment across GMPLS-controlled networks while providing a viable solution for dynamic resource control that takes into account operational issues for the integration of GMPLS capabilities within NGN architecture (i.e., supported interfaces, actual node capabilities). An NGN prototype implementing the proposed architectural enhancement is also presented as a proof of concept. The prototype highlights how the extended ITU-T NGN can set-up Multimedia over IP (MoIP) services using GMPLS-controlled transport objects.

A novel approach to user data federation in Next‐Generation Networks

AbstractUser Profile Management (UPM) is an essential feature to support applications in Next‐Generation Network (NGN). Its actual realization depends on standardization of information and preferences and the ways in which user data are expressed and handled. To this end, an NGN may support different approaches; among them, the ‘federated approach’ seems particularly relevant, as it fits the very common scenario in which many existing services and devices already contain specific settings and preferences that are however unrelated to any other. This paper proposes a novel, totally distributed solution for data federation, where authorization, management of data localization and synchronization of federated data are thought to be part of the meta information that may be associated with each data element, rather than being external resources or built‐in functions, as in legacy solutions. First, the present paper introduces the work on personalization and UPM and the NGN architecture being done at ETSI. Then, the paper illustratesthe work on user data interoperability performed at OASIS XDI TC. Finally, based on these inputs, it explains how to combine them into a novel solution (which is not part of ETSI or OASIS specifications). Copyright © 2009 John Wiley & Sons, Ltd.

Enabling layered video coding for IMS-based IPTV home services

Nowadays IPTV services are gaining attention from both providers and end users. There is a large effort toward the integration of these services into emerging next-generation network architectures. In particular, one of the most relevant solutions is being proposed by ETSI-TISPAN and is based on the IP multimedia subsystem. This article focuses on introducing layered video coding into TISPAN IMS-based IPTV architecture, allowing cost-effective efficient solutions both for residential users and providers (e.g., flexible support of heterogeneous devices, live mosaics, adaptive video quality based on device and/or network capabilities). The advantages of using layered video coding in the TISPAN IPTV solution are analyzed and illustrated with a set of use cases. Furthermore, this solution has been integrated into a multimedia testbed in order to validate the presented proposal.

Functional Architecture for NGN-Based Personalized IPTV Services

IPTV is one of the most highly visible services to emerge as part of the development of next generation network (NGN). IPTV services over manageable broadband link from a provider will be one of the ultimate goals of the broadband revolution using NGN. In this paper, we analyze IPTV architecture developed by ITU-T and provide functional architecture for NGN-based IPTV services according to functional mapping between IPTV and NGN. For this, we provide the detailed functional architecture and relevant operations with other functional blocks and present the harmonized architecture between IPTV and NGN for NGN-based IPTV services with the alignment with existing NGN architecture. As challenging architectural issues, we also introduce personalized IPTV services based on Web-based open platform in NGN environment and illustrate functional architecture and service examples for Web-based personalized IPTV services.

A fraud management system architecture for next-generation networks

This paper proposes an original architecture for a fraud management system (FMS) for convergent. Next-generation networks (NGNs), which are based on the Internet protocol (IP). The architecture has the potential to satisfy the requirements of flexibility and application-independency for effective fraud detection in NGNs that cannot be met by traditional FMSs. The proposed architecture has a thorough four-stage detection process that analyses billing records in IP detail record (IPDR) format – an emerging IP-based billing standard – for signs of fraud. Its key feature is its usage of neural networks in the form of self-organising maps (SOMs) to help uncover unknown NGN fraud scenarios. A prototype was implemented to test the effectiveness of using a SOM for fraud detection and is also described in the paper.

Next-generation networks application traffic modeling

One of the key selling points of the next-generation network (NGN) architecture is that it facilitates the rapid deployment of numerous applications onto the same core infrastructure. Before this advantage can be fully realized, however, new methods for traffic estimation are needed to assess the performance impact of new applications and ensure adequate quality of service (QoS). We have created a method to assist network operators with such estimates as part of comprehensive design, capacity planning, or business case analyses. The method identifies the key input parameters that impact traffic, provides a library of application building blocks, assembles them to model new applications quickly, and provides a method for calculating the aggregate signaling and bearer traffic for a given set of applications. In this way, a new network model for each application can be created quickly, and the impact of introducing a new set of applications can be estimated without requiring detailed systems engineering expertise on each aspect of the network.

Next-generation access network architectures for video, voice, interactive gaming, and other emerging applications: challenges and directions

Internet access was the main service supported in legacy access networks via asynchronous transfer mode (ATM)-based digital subscriber line access multiplexers (DSLAMs) and aggregation networks. The broadband remote access server (BRAS) was the Internet Protocol (IP) edge router, and it provided various services including service routing, Point-to-Point Protocol (PPP) handling, shaping, scheduling, and policy-based controls. This architecture is being increasingly replaced by an Ethernet-based aggregation network with potentially multiple broadband network gateways (BNGs) replacing the single BRAS. The migration to Ethernet-based networks is partly driven by the high bandwidth needs of applications such as video on demand (VoD), IP television (IPTV), and the ability to support these applications at cost-effective points. Other drivers that are emerging to further shape the next generation of access networks are examined in this paper. In particular, we focus closely on emerging video and voice applications and the new challenges and requirements they bring. The set of applications and issues that we consider is by no means comprehensive. They have been selected as they pose some interesting challenges and have significant impact on the access network functionality and architecture. For video traffic, we examine the challenges for providing high video quality, fast response for IPTV channel change, and content distribution. For voice, we examine the challenges of emergency standalone operation. Finally, we examine aspects of quality of service (QoS) management, resource control, and network resiliency mechanisms for these emerging applications. We see that the access network needs to become extremely application aware and dynamic and move beyond the traditional IP layer 2/3 forwarding functions in order to meet these challenges effectively.

Location-based assisted handover for the IP Multimedia Subsystem

The IP Multimedia Subsystem (IMS) is one promising candidate for merging currently deployed circuit-switched and packet-switched voice and data networks into a service-based All-IP architecture. One requirement common to all of these Next Generation Network (NGN) architectures is seamless user mobility – a mandatory feature in order to match with the tremendous success of today’s circuit-switched GSM voice networks. In addition most NGN architectures mandate the support for heterogeneous access technologies like WLAN, WiMAX, GPRS/EDGE, UMTS/HSDPA which raises the need for seamless vertical handover between these access technologies. Despite ongoing standardisation and technology developments like Generic Access Network (GAN), Voice Call Continuity (VCC) or Media Independent Handover (MIH, IEEE 802.21) we argue that there is currently no solution to enable seamless and application-transparent vertical handover in the IMS. In this paper, we review vertical handover standards for IMS and propose a novel vertical handover architecture which relies on geographical location and global network information as primary trigger or support for handover initiation. The underlying Session Initiation Protocol (SIP) notification framework – a Terminal-Centric IMS Location Enabler (LE) – is based on the key concept that location information is one specific kind of presence information which is optimally provisioned by mobile devices: the terminal knows best where it is located. The Location Enabler solicits notifications from the mobile device on specific events – e.g., entering or leaving specific geographical areas – thus dramatically reducing the amount of data transferred over the radio interface when compared to tracking or polling. The SIP registration and Re-Invite message flow is used to convey all handover-relevant information between the IMS core network and the mobile terminal. Using accurate access network measurement results the paper presents a performance estimation of the proposed vertical handover architecture with respect to handover duration and required handover area width at different velocities.

IP MULTIMEDIA SUBSYSTEM - Application-Level QoS Negotiation and Signaling for Advanced Multimedia Services in the IMS

The IP multimedia subsystem (IMS) has been recognized as a reference next-generation network architecture for offering multimedia services over an Internet Protocol (IP)-based infrastructure. One of the key benefits of the IMS is efficient and flexible introduction of new services and access to third-party application providers, thanks to standard interfaces and standardized service capabilities. To support novel media-rich applications across a wide range of user devices and access networks, IMS must support negotiable quality of service (QoS) for IP multimedia sessions. In this article, we describe the application-level QoS signaling as specified by the 3GPP and propose some enhancements based on advanced QoS parameter matching and optimization functionality to be included along the signaling path. We outline various signaling flow scenarios and discuss them in the context of a case study involving an IMS-supported 3D virtual environment, featuring a treasure-hunt-like game.

Introduction to the Functional Architecture of NGN

In July 2006, International Telecommunication Union-Telecommunication Standardization Sector (ITU-T) Study Group 13 initiated the approval process for a batch of framework Recommendations on the Next Generation Network (NGN) Release 1. One of the new Recommendations, Y.2012, illustrates the NGN from the viewpoint of a functional architecture consisting of various functional blocks, namely functional entities. In conjunction with this Recommendation, this paper explains how the NGN can be built and how the NGN utilizes functional entities to provide expected services and required capabilities. This paper also identifies open issues for extending the functional architecture towards Release 2.