Giuseppe Carella

Service Function Chaining in Next Generation Networks: State of the Art and Research Challenges

Service function chaining is a network capability that provides support for application-driven-networking through the ordered interconnection of service functions. The lifecycle management of service function chains is enabled by two recently emerged technologies, software defined networking and network function virtualization, that promise a number of efficiency, effectiveness, and flexibility gains. This article introduces a service function chaining taxonomy that considers architecture and performance dimensions as the basis for the subsequent stateof- the-art analysis. The article concludes with a gap analysis of existing solutions and the identification of future research challenges.

Cloudified IP Multimedia Subsystem (IMS) for Network Function Virtualization (NFV)-based architectures

The maturity reached by virtualisation technology enabled great innovation for efficient applications and services development and delivery, independent of the underlying hardware equipment, especially with the large deployment of off-the-shelf hardware based cloud infrastructures. In order to take advantage of this technology, the existing network functions have to be developed and adapted to the new paradigm. However, traditional telecom services are still implemented on dedicated hardware resulting in high deployment and maintenance costs compared to the other already cloudified services. ETSI Network Functions Virtualisation (NFV) aims to fill this gap by applying to telecom the virtualisation technologies. This paper introduces a set of three software architectures for efficient virtualisation of IP Multimedia Subsystem (IMS) in different operator environments responding to the high level requirements of the ETSI NFV use case for virtualizing operator core network functions. Additionally, a management architecture for simplifying the deployment and runtime orchestration of such a virtual service on top of a cloud infrastructure is presented. Furthermore, one of the IMS software architectures was implemented based on the Fraunhofer FOKUS Open IMS Core, measured and evaluated on top of an OpenStack cloud.

BonFIRE: The Clouds and Services Testbed

BonFIRE is a multi-site test bed that supports testing of Cloud-based and distributed applications. BonFIRE breaks the mould of commercial Cloud offerings by providing unique functionality in terms of observability, control, advanced Cloud features and ease of use for experimentation. A number of successful use cases have been executed on BonFIRE, involving industrial and academic users and delivering impact in diverse areas, such as media, e-health, environment and manufacturing. The BonFIRE user-base is expanding through its free, Open Access scheme, daily carrying out important research, while the consortium is working to sustain the facility beyond 2014.

Multi-tenancy for Virtualized Network Functions

The proliferation of cloud computing techniques has created a multitude of applications for network services deployments, enabled by the adoption of Software Defined Networks (SDN) and Network Functions Virtualization (NFV) paradigms. Mobile Network Operators (MNOs) also have the opportunity to leverage these technologies to enable the delivery of traditional networking functionality making use of cloud technologies. The benefit is cost reduction in the CAPEX and OPEX of the network infrastructure. Furthermore, multiple MNOs could share Virtualized Network Functions (VNFs) while maintaining separate logical data and control planes. This work investigates how those VNFs, in particular the Evolved Packet Core (EPC) Network Service (NS), can be shared using Virtual Tenant Networks (VTN) techniques. VTN provides a logical separation between data and control plane in virtualized networks. The design, implementation, and preliminary evaluations of such deployments are showcased in this paper, using open-source tools and readily available research playgrounds.

Toward a Fully Cloudified Mobile Network Infrastructure

Cloud computing enables the on-demand delivery of resources for a multitude of services and gives the opportunity for small agile companies to compete with large industries. In the telco world, cloud computing is currently mostly used by mobile network operators (MNO) for hosting non-critical support services and selling cloud services such as applications and data storage. MNOs are investigating the use of cloud computing to deliver key telecommunication services in the access and core networks. Without this, MNOs lose the opportunities of both combining this with over-the-top (OTT) and value-added services to their fundamental service offerings and leveraging cost-effective commodity hardware. Being able to leverage cloud computing technology effectively for the telco world is the focus of mobile cloud networking (MCN). This paper presents the key results of MCN integrated project that includes its architecture advancements, prototype implementation, and evaluation. Results show the efficiency and the simplicity that a MNO can deploy and manage the complete service lifecycle of fully cloudified, composed services that combine OTT/IT- and mobile-network-based services running on commodity hardware. The extensive performance evaluation of MCN using two key proof-of-concept scenarios that compose together many services to deliver novel converged elastic, on-demand mobile-based but innovative OTT services proves the feasibility of such fully virtualized deployments. Results show that it is beneficial to extend cloud computing to telco usage and run fully cloudified mobile-network-based systems with clear advantages and new service opportunities for MNOs and end-users.

Elasticity as a service for federated cloud testbeds

This paper presents the design, real-world deployment and evaluation of FOKUS Cloud Brokers core component, the Elasticity Engine. The engine enables Elasticity as a Service, by providing dynamic and optimized cloud resource allocation for federated cloud platform environments. Deployed and evaluated within the European large-scale, multi-site cloud experimental facility BonFIRE this work provides a realistic assertion of the performance of the Elasticity Engines cloud resource allocation performance. Being a very typical scenario for todays cloud platform users who are having the free choice to select amongst multiple cloud platform offerings, this work provides a rough, but realistic assertion on what can be expected of an elastic multi-cloud resource provisioning system in terms of performance.

Network-aware Cloud Brokerage for telecommunication services

Cross-domain Cloud Brokering mechanisms enable elastic and cost-efficient utilization of cloud resources distributed across multiple cloud platforms. They are allowing cloud service providers to cost-efficiently exploit the growing competition in the cloud provider market. Existing elastic cloud computing solutions are optimizing cloud resource utilization merely within a specific cloud provider platform. Optimized multi-site Cloud Brokering mechanisms on the other hand enable economically efficient cloud resource consumption. However, in order to satisfy QoS requirements of cloud-based, real-time multimedia telecommunication services, enhanced QoS assurance mechanisms for multi-site cloud brokers need to be in place. In this paper we optimize and evaluate the FOKUS Cloud Broker solution through experimentation in a multi-site cloud testing facility which allows experimentation under different networking conditions, i.e. over standard, best-effort internet connections across several cloud platforms in Europe, as well as under fully controllable network conditions. The result of this work shows the benefits of network-aware cloud brokering mechanisms. Moreover, this paper shows the terms under which additional real-time data on network performance is useful for enhancing cloud brokering mechanisms, especially for meeting QoS requirements of realtime communication services. This work also shows how initial, service-specific correlation of network, service and host performance parameters, furthermore improves the overall cloud brokering performance.

Optimization of Elastic Cloud Brokerage Mechanisms for Future Telecommunication Service Environments

Cloud computing mechanisms and cloud-based services are currently revolutionizing Web as well as telecommunication service platforms and service offerings. Apart from providing infrastructures, platforms and software as a service, mechanism for dynamic allocation of compute and storage resources on-demand, commonly termed as “elastic cloud computing” account for the most important cloud computing functionalities. Resource elasticity allows not only for efficient internal compute and storage resource consumption, but also, through so called hybrid cloud computing mechanisms, for dynamic utilization of external resources on-demand. This capability is especially useful in order to cost-efficiently cope with peakworkloads, allowing service providers to significantly reduce usually required over-provisioned service infrastructures, allowing for “pay-per-use” cost models. With a steadily growing number of cloud providers and with the proliferation of unified cloud computing interfaces, service providers are given free choice of flexibly selecting and utilizing cloud resources from different cloud providers. Cloud brokering systems allow for dynamic selection and utilization of cloud computing resources based on functional (e.g. QoS, SLA, energy consumption) as well as nonfunctional criteria (e.g. costs). The presented work focuses on enhanced cloud brokering mechanisms for telecommunication service platforms, enabling quality telecommunication service assurance, still optimizing cloud resources consumption, i.e. saving costs and energy. Furthermore this work shows that by combining cloud brokering mechanisms with standardized telecommunication service brokering mechanisms an even greater benefit for telecommunication service providers can be achieved as this enables an even better cost-efficiency since different user segments can seamlessly be served by allocating different cloud resources to them in a policy-driven manner.

Near optimal service function path instantiation in a multi-datacenter environment

Service Function Chaining (SFC) supports services/applications through linking an ordered list of service functions (such as firewalls, deep packet inspections and load balancers) in the network. Using Software Defined Networking (SDN) and Network Function Virtualization (NFV) provides a simpler and shorter SFC process. In order to provide high-availability on a multi-site SFC, it is required a flexible algorithm able to properly select Service Function instances while creating the Service Function Path (SFP). This paper presents a new service function selection algorithm providing a flexible tradeoff between the SFP distance and the loads per service function instances at the deployment stage. The flexible tradeoff provided in the algorithm can be adjusted by a parameter. This parameter value can differ among different types of SFCs based on the service/application (real time or non-real time) dedicated for its SFC. Matlab has been utilized for validating it with different scenarios. It is also compared to other existing algorithms such as, load balancing and shortest path. The results showed that the proposed algorithm could provide the best SFP end-to-end distance performance as the shortest path algorithm for the real time services/applications, and that will result a good Quality of Service (QoS) performance for real time services/applications. Furthermore, the proposed algorithm provides an acceptable load distribution over the available service functions instances better than shortest path algorithm and not far from and load balancing algorithms.

Resilient orchestration of Service Functions Chains in a NFV environment

Service Function Chaining (SFC) defines the concept of linking ordered Service Functions (SFs) through network technologies to support specific application requirements. SFC exploits Software Defined Networking (SDN) and Network Function Virtualization (NFV) technologies to achieve the creation, modification and deletion of SFC in a cost efficient and rapid way. However, during the runtime phase, SFs are exposed to the risk of failures, which results in an end-to-end failure at the application level. For this reason, this paper introduces the concept of a resilient SFC Orchestrator capable of deploying SF Chains following the ETSI NFV architectural model, as well as controlling the runtime phase rerouting the traffic to a different path in case of appearing faults. Furthermore, the concept is exemplified as an addition to the current NFV architecture and evaluated in a NFV environment making use of the Fraunhofer FOKUS Open Baton toolkit in an OpenStack and OpenDayLight based environment. Finally, the measured results show that the Service Function Path (SFP), and therefore their provided services, can be recovered in a few seconds.