End-to-end Mobile Network Slicing

Wireless networks have gone through several years of evolution until now and will continue to do so in order to cater for the varying needs of its users. These demands are expected to continue to grow even more in the future, both in size and variability. Hence, the 5G technology needs to consider these variabilities in service demands and potential data explosion which could accompany users’ demands at the core of its architecture. For 5G mobile network to handle these foreseen challenges, network slicing \cite{c13} is seen as a potential path to tread as its standardization is progressing. In light of the proposed 5G network architecture and to support and end-to-end mobile network slicing, we implemented radio access network (RAN) slicing over a virtualized evolved Node B (eNodeB) and ensured multiple core network slices could communicate through it successfully. Our results, challenges and further research path are presented in this thesis report

QoS Enabled Video Telephony with a Virtualized HSS in a 4G EPC Environment

Video Telephony is the real time exchange of voice and video between end-users. It is the basis of a wide range of applications (e.g. Multiparty games, distance learning). Quality of service (QoS) enables network performance control for meeting specific applications and/or end-user requirements. It is a differentiating factor for service providers. Evolved Packet Core (EPC) is the new core network for 3GPP 4G networks. Home Subscriber Server (HSS) is the standardized master database of 3GPP next generation networks including video telephony networks and EPC. It contains the subscription related information that is needed to support the network entities when they handle sessions. The constant increase in the number of subscribers is one of the challenges for future mobile networks including video telephony networks and EPC. Virtualization is a technique used to emulate the physical characteristics of resources. It enables efficiency in resource usage and is a key technology for scalability and elasticity. This thesis proposes an architecture for QoS Enabled video telephony with a Virtualized HSS (VHSS) in a 3GPP 4G environment. It makes two main contributions. Firstly, it proposes a differentiated QoS service delivery platform that relies on EPC. This platform enables the provisioning of a refined differentiated QoS scheme which allows prioritization between different sessions of a same video telephony application running on a same network. This new scheme is a differentiating factor for service providers. Second it proposes a preliminary mechanism for a scalable and elastic HSS in order to cope with the increasing number of subscribers. This is done by decomposing the HSS into three main layers (diameter layer, database computation layer and storage layer). Each of these layers are virtualized and can grow/shrink independently. We have built a proof of concept prototype to demonstrate the feasibility of the proposed architecture. Performance measurements have also been made to evaluate viability

Flexible cross layer optimization for fixed and mobile broadband telecommunication networks and beyond

In der heutigen Zeit, in der das Internet im Allgemeinen und Telekommunikationsnetze im Speziellen kritische Infrastrukturen erreicht haben, entstehen hohe Anforderungen und neue Herausforderungen an den Datentransport in Hinsicht auf Effizienz und Flexibilität. Heutige Telekommunikationsnetze sind jedoch rigide und statisch konzipiert, was nur ein geringes Maß an Flexibilität und Anpassungsfähigkeit der Netze ermöglicht und darüber hinaus nur im begrenzten Maße die Wichtigkeit von Datenflüssen im wiederspiegelt. Diverse Lösungsansätze zum kompletten Neuentwurf als auch zum evolutionären Konzept des Internet wurden ausgearbeitet und spezifiziert, um diese neuartigen Anforderungen und Herausforderungen adäquat zu adressieren. Einer dieser Ansätze ist das Cross Layer Optimierungs-Paradigma, welches eine bisher nicht mögliche direkte Kommunikation zwischen verteilten Funktionalitäten unterschiedlichen Typs ermöglicht, um ein höheres Maß an Dienstgüte zu erlangen. Ein wesentlicher Indikator, welcher die Relevanz dieses Ansatzes unterstreicht, zeichnet sich durch die Programmierbarkeit von Netzwerkfunktionalitäten aus, welche sich aus der Evolution von heutigen hin zu zukünftigen Netzen erkennen lässt. Dieses Konzept wird als ein vielversprechender Lösungsansatz für Kontrollmechanismen von Diensten in zukünftigen Kernnetzwerken erachtet. Dennoch existiert zur Zeit der Entstehung dieser Doktorarbeit kein Ansatz zur Cross Layer Optimierung in Festnetz-und Mobilfunknetze, welcher der geforderten Effizienz und Flexibilität gerecht wird. Die übergeordnete Zielsetzung dieser Arbeit adressiert die Konzeptionierung, Entwicklung und Evaluierung eines Cross Layer Optimierungsansatzes für Telekommunikationsnetze. Einen wesentlichen Schwerpunkt dieser Arbeit stellt die Definition einer theoretischen Konzeptionierung und deren praktischer Realisierung eines Systems zur Cross Layer Optimierung für Telekommunikationsnetze dar. Die durch diese Doktorarbeit analysierten wissenschaftlichen Fragestellungen betreffen u.a. die Anwendbarkeit von Cross Layer Optimierungsansätzen auf Telekommunikationsnetzwerke; die Betrachtung neuartiger Anforderungen; existierende Konzepte, Ansätze und Lösungen; die Abdeckung neuer Funktionalitäten durch bereits existierende Lösungen; und letztendlich den erkennbaren Mehrwert des neu vorgeschlagenen Konzepts gegenüber den bestehenden Lösungen. Die wissenschaftlichen Beiträge dieser Doktorarbeit lassen sich grob durch vier Säulen skizzieren: Erstens werden der Stand der Wissenschaft und Technik analysiert und bewertet, Anforderungen erhoben und eine Lückenanalyse vorgenommen. Zweitens werden Herausforderungen, Möglichkeiten, Limitierungen und Konzeptionierungsaspekte eines Modells zur Cross Layer Optimierung analysiert und evaluiert. Drittens wird ein konzeptionelles Modell - Generic Adaptive Resource Control (GARC) - spezifiziert, als Prototyp realisiert und ausgiebig validiert. Viertens werden theoretische und praktische Beiträge dieser Doktorarbeit vertiefend analysiert und bewertet.As the telecommunication world moves towards a data-only network environment, signaling, voice and other data are similarly transported as Internet Protocol packets. New requirements, challenges and opportunities are bound to this transition and influence telecommunication architectures accordingly. In this time in which the Internet in general, and telecommunication networks in particular, have entered critical infrastructures and systems, it is of high importance to guarantee efficient and flexible data transport. A certain level of Quality-of-Service (QoS) for critical services is crucial even during overload situations in the access and core network, as these two are the bottlenecks in the network. However, the current telecommunication architecture is rigid and static, which offers very limited flexibility and adaptability. Several concepts on clean slate as well as evolutionary approaches have been proposed and defined in order to cope with these new challenges and requirements. One of these approaches is the Cross Layer Optimization paradigm. This concept omits the strict separation and isolation of the Application-, Control- and Network-Layers as it enables interaction and fosters Cross Layer Optimization among them. One indicator underlying this trend is the programmability of network functions, which emerges clearly during the telecommunication network evolution towards the Future Internet. The concept is regarded as one solution for service control in future mobile core networks. However, no standardized approach for Cross Layer signaling nor optimizations in between the individual layers have been standardized at the time this thesis was written. The main objective of this thesis is the design, implementation and evaluation of a Cross Layer Optimization concept on telecommunication networks. A major emphasis is given to the definition of a theoretical model and its practical realization through the implementation of a Cross Layer network resource optimization system for telecommunication systems. The key questions answered through this thesis are: in which way can the Cross Layer Optimization paradigm be applied on telecommunication networks; which new requirements arise; which of the required functionalities cannot be covered through existing solutions, what other conceptual approaches already exist and finally whether such a new concept is viable. The work presented in this thesis and its contributions can be summarized in four parts: First, a review of related work, a requirement analysis and a gap analysis were performed. Second, challenges, limitations, opportunities and design aspects for specifying an optimization model between application and network layer were formulated. Third, a conceptual model - Generic Adaptive Resource Control (GARC) - was specified and its prototypical implementation was realized. Fourth, the theoretical and practical thesis contributions was validated and evaluated

NFV Management and Orchestration in Large-Scale Distributed Systems

Network Functions Virtualization (NFV) radically transforms the way network operators design and manage network services, promising a lot of potential benefits such as agility, flexibility, reduction of CAPEX and OPEX. It eliminates the dependency between the network function software and hardware enabling pure-software based network function that runs on commodity hardware, called Virtualized Network Function (VNF). NFV, along with other emerging technologies such as Software-Defined Networking (SDN), enables network operators to create dynamic and programmable network services, wherein VNFs are deployed on-demand, dynamically chained and optimized over time to cope with emerging business needs. The European Telecommunications Standards Institute (ETSI) developed the NFV Management and Orchestration (MANO) framework, which consists of Virtualized Infrastructure Manager (VIM), VNF Manager (VNFM) and NFV Orchestrator (NFVO), in order to provide network operators with the sophisticated capabilities needed to manage the dynamic aspects of infrastructure, VNFs and network services. This thesis elaborates and addresses key architectural and algorithmic research challenges related to the NFV management and orchestration in distributed and large-scale systems. We look at orchestration scalability from an architectural perspective and propose to leverage two-layer hierarchical service orchestration to manage network services over distributed infrastructure. We also propose an architecture of Virtual Network Platform-as-a-Service (VNPaaS) that utilizes the hierarchical orchestration to offer next-generation mobile networks as-a-service. The architecture is illustrated by offering the 3GPP Home Subscriber Server (HSS) as-a-Service (HSSaaS), in which the HSS is decomposed into VNFs with a granularity finer than what is known today. On the algorithmic side, a key challenge is to identify the number and location of the NFVO and VNFM functional blocks since they have a significant impact on the overall system cost and performance, among others. In particular, we tackle the online placement of VNFM to enable network operators to adjust the number and location of VNFMs in response to variation in workload. There, we assume a fixed location of NFVO and aim at minimizing the operational cost. Owing to its complexity, we propose a tabu search heuristic and numerically show that it is faster than the mathematical formulation by many orders of magnitude. We further study the joint placement of NFVO and VNFM. We first address the problem in the context of the multi-orchestrator system and seek to minimize the number of NFVOs and VNFMs. We mathematically formulate the problem and propose a two-step placement heuristic to solve the problem efficiently. Finally, we investigate the same problem in the context of single- and multi-orchestrator systems providing a comparative study of the worst-case delay in both scenarios. We also propose a late acceptance hill-climbing heuristic to solve the problem in a reasonable time frame

Simulation and Performance Analysis of Software-Based Mobile Core Network Architecture (SBMCNA) using OMNeT++

Abstract— Software defined Networking (SDN) represent the future framework for the mobile networks. This paper discusses the required modifications within the EPC in order to overcome some of the limitations of the current EPS, these modifications include introducing an SDN based solution Software Based Mobile Core Network Architecture (SBMCNA), we also show that Openflow protocol 1.3 has been extended to develop two methods to support GPRS Tunnelling Protocol (GTP) operations. The use of an intelligent Forwarding device (FD) were proposed to reduce the signalling load. SBMCNA were built on OMNeT++ by extending simuLTE [12] and Openflow 1.3 [13] modules. Load balancing and resiliency were used to demonstrate the capability of the proposed system to reduce the signalling load. The preliminary results of the system performance are presented

Cognition-inspired 5G cellular networks: a review and the road ahead

Despite the evolution of cellular networks, spectrum scarcity and the lack of intelligent and autonomous capabilities remain a cause for concern. These problems have resulted in low network capacity, high signaling overhead, inefficient data forwarding, and low scalability, which are expected to persist as the stumbling blocks to deploy, support and scale next-generation applications, including smart city and virtual reality. Fifth-generation (5G) cellular networking, along with its salient operational characteristics - including the cognitive and cooperative capabilities, network virtualization, and traffic offload - can address these limitations to cater to future scenarios characterized by highly heterogeneous, ultra-dense, and highly variable environments. Cognitive radio (CR) and cognition cycle (CC) are key enabling technologies for 5G. CR enables nodes to explore and use underutilized licensed channels; while CC has been embedded in CR nodes to learn new knowledge and adapt to network dynamics. CR and CC have brought advantages to a cognition-inspired 5G cellular network, including addressing the spectrum scarcity problem, promoting interoperation among heterogeneous entities, and providing intelligence and autonomous capabilities to support 5G core operations, such as smart beamforming. In this paper, we present the attributes of 5G and existing state of the art focusing on how CR and CC have been adopted in 5G to provide spectral efficiency, energy efficiency, improved quality of service and experience, and cost efficiency. This main contribution of this paper is to complement recent work by focusing on the networking aspect of CR and CC applied to 5G due to the urgent need to investigate, as well as to further enhance, CR and CC as core mechanisms to support 5G. This paper is aspired to establish a foundation and to spark new research interest in this topic. Open research opportunities and platform implementation are also presented to stimulate new research initiatives in this exciting area