Ishan Vaishnavi

SDN-based 5G mobile networks: architecture, functions, procedures and backward compatibility

In this paper, we describe an SDN-based plastic architecture for 5G networks, designed to fulfill functional and performance requirements of new generation services and devices. The 5G logical architecture is presented in detail, and key procedures for dynamic control plane instantiation, device attachment, and service request and mobility management are specified. Key feature of the proposed architecture is flexibility, needed to support efficiently a heterogeneous set of services, including Machine Type Communication, Vehicle to X and Internet of Things traffic. These applications are imposing challenging targets, in terms of end-to-end latency, dependability, reliability and scalability. Additionally, backward compatibility with legacy systems is guaranteed by the proposed solution, and Control Plane and Data Plane are fully decoupled. The three levels of unified signaling unify Access, Non-access and Management strata, and a clean-slate forwarding layer, designed according to the software defined networking principle, replaces tunneling protocols for carrier grade mobility. Copyright

A novel approach to virtual networks embedding for SDN management and orchestration

The development of methodologies to manage and orchestrate virtualised resources and network functions is a fundamental enabler for optimally utilising physical ICT infrastructures. Algorithms for optimal location (embedding) of network functions, IT and CT resources, services and corresponding states, especially at the network edge, will enable new business models and provide a key competitive advantage to network administrators. This paper introduces a novel Mixed Integer Programming (MIP) formulation for a coordinated node and link mapping onto the underlying network infrastructure. Extensive simulation results show that the proposed algorithm outperforms prior art formulations: two digit gains were attained in terms of resources utilisation, embedding, revenues and, especially convergence time. The proposed methodology is applicable to a number of relevant use cases, as constraints and objective functions can be flexibly defined by network operators.

Virtual Links Mapping in Future SDN-Enabled Networks

Software defined networking (SDN) has emerged as an efficient network technology for lowering operating costs through simplified hardware, software and management. Specific research focus has been placed to achieve a successful carrier grade network with SDN, in terms of scalability, reliability, QoS and service management. In the literature, very little material is currently available on traffic engineering (TE) using this technology. This paper presents a novel mixed integer linear programming (MILP) formulation for a centralised controller to calculate optimal end-to-end virtual paths over the underlying network infrastructure, considering multiple requests simultaneously. Extensive simulation results, over a wide range of underlying network topologies and input parameters, demonstrate that the proposed algorithm outperforms traditional shortest path first (SPF) approaches. In some cases, up to 30 % more virtual connections were satisfactorily mapped onto the same substrate, independent of the number of physical nodes.

Recursive, hierarchical embedding of virtual infrastructure in multi-domain substrates

One of the main goals of future telecom networks is to achieve softwarization of network functions. A requirement to achieve this softwarization is the ability to construct on-demand networks across multi-domain network and/or cloud service providers (NCSP). Most current algorithms and MILP formulations that solve the multi-domain embedding problem work on a flat infrastructure using simplified physical resource models. In this paper we propose an abstraction of the physical network domains to make the multiple domains appear as a pseudo flat infrastructure enabling re-use of existing flat infrastructure embedding algorithms with a few modifications. We incorporate these modifications in our previously proposed embedding ILP formulation. Our results show that we can speed up the process of embedding in large multi-domain networks considerably while trading off some efficiency in resource utilization due to abstraction.

Network Resource Management and QoS in SDN-Enabled 5G Systems

Virtual Network Embedding (VNE) is considered a key technology to instantiate and operate Data and Control planes in next generation (5G) SDN-based Networks. Within this domain, Network Resource Management (NRM) is an essential feature to allow efficient resource utilisation, to enable network slicing and to guarantee fairness among the supported QoS classes. This paper presents and evaluates three alternative NRM policies: Full Sharing, Full Split and Russian Dolls. Policies define how different QoS classes share the available bandwidth on per link basis. The policies have been integrated in a MIP-based Virtual Link Mapping formulation (VLM+) supporting multi-constrained end to end QoS. Simulation results show different policies can suit different network operators requirements. Also, results highlight Russian Dolls significantly outperforms other policies in terms of Embedding Rate and Link Utilisation, still preserving fairness among QoS Classes. VLM+ Convergence Time has also been evaluated, showing all policies are compatible with timing requirements for a real 5G system implementation.

5GEx: realising a Europe-wide multi-domain framework for software-defined infrastructures

Market fragmentation has resulted in a multitude of network and cloud/data center operators, each focused on different countries, regions and technologies. This makes it difficult and costly to create infrastructure services spanning multiple domains, such as virtual connectivity or compute resources. In this article, we discuss the goals and work being done within the 5GEx 5G Exchange project in realising a Europe-wide multi-domain platform. This platform aims at enabling cross-domain orchestration of services over multiple administrations or over multi-domain single administrations in the context of emerging 5G networking. The 5GEx vision is based on introducing a unification via network function virtualisation/software-defined networking compatible multi-domain orchestration for networks, clouds and services. We describe the motivation and 5GEx vision, the adopted architecture and the next steps in terms of implementation and experimentation. Copyright

Modeling Reliability Requirements in Coordinated Node and Link Mapping

High performance systems require high levels of reliability. Many functions involved in telecommunication and IT networks have reliability requirements that can only be achieved by introducing redundant resources. In the telecom sector, recently, there has been a significant effort on moving carrier grade systems and functions to virtualized network infrastructure. The management and coordination of those virtualized systems to achieve an optimal mapping (or embedding) to the physical resources that host them is known as virtual resource orchestration. In our prior work we introduced a novel model, based on Mixed Integer Programming (MIP) problem formulation, as one significant way of achieving this optimality in embedding. This paper extends the model to include reliability requirements, improving prior art techniques as well as implementing a novel approach, denoted as reliability assurance. The confidence of the target reliability of the embedded virtual graphs can be traded with the efficiency of the substrate utilization. Extensive simulation results show that our model provides embedding rates and infrastructure utilization comparable with prior art while fulfilling high reliability requirements.

Orchestration of Network Services across multiple operators: The 5G Exchange prototype

Future 5G networks will rely on the coordinated allocation of compute, storage, and networking resources in order to meet the functional requirements of 5G services as well as guaranteeing efficient usage of the network infrastructure. However, the 5G service provisioning paradigm will also require a unified infrastructure service market that integrates multiple operators and technologies. The 5G Exchange (5GEx) project, building heavily on the Software-Defined Network (SDN) and the Network Function Virtualization (NFV) functionalities, tries to overcome this market and technology fragmentation by designing, implementing, and testing a multi-domain orchestrator (MdO) prototype for fast and automated Network Service (NS) provisioning over multiple-technologies and spanning across multiple operators. This paper presents a first implementation of the 5GEx MdO prototype obtained by extending existing open source software tools at the disposal of the 5GEx partners. The main functions of the 5GEx MdO prototype are showcased by demonstrating how it is possible to create and deploy NSs in the context of a Slice as a Service (SlaaS) use-case, based on a multi-operator scenario. The 5GEx MdO prototype performance is experimentally evaluated running validation tests within the 5GEx sandbox. The overall time required for the NS deployment has been evaluated considering NSs deployed across two operators.

Towards zero latency Software Defined 5G Networks

This paper presents a novel SDN-based 5G network architecture, conceived to support next generation delay critical services. Following a 4G systems delay analysis, new design principles towards a “zero latency” network are discussed. Based on these guidelines, and under the assumption of a broad adoption of emerging SDN and NFV technologies, a novel “plastic” architecture for 5G systems is devised. Together with the architecture, new procedures for device attachment, connectivity and mobility management are presented. Latency improvements from the proposed architecture have been estimated up to 75% compared to 3GPP Release 12 compliant 4G systems.

VNetMapper: A fast and scalable approach to virtual networks embedding

Virtual network embedding is considered an important problem to solve in order to make infrastructure virtualization economically reasonable. The most efficient algorithms proposed so far define link and node mappings as optimal solutions of Integer Programming (IP) problems. They exhibit reasonably good performance only for small problem instance sizes, including few tens of nodes and links per physical substrate, few nodes and links per virtual request and a dozen of virtual requests to handle in parallel. However, we find these instances too small to be of any practical use. To address this scalability issue, we propose VNetMapper, an algorithm to solve the virtual network embedding problem based on an integer program formulation with appropriately selected objective function, variables and the set of constraints tuned to give an optimal performance. We show through simulations that VNetMapper can quickly, within seconds, solve large problem instances, involving physical substrates with hundreds of nodes and thousands of links and batches of hundreds of virtual network requests. By identifying exact properties that make VNetMapper so fast and scalable, we present guidelines for designing scalable integer programs.