Wouter Tavernier

Network service chaining with optimized network function embedding supporting service decompositions

The rise of Software-Defined Networking (SDN) and Network Function Virtualization (NFV) introduce opportunities for service providers to reduce CAPEX/OPEX and to offer and quickly deploy novel network services. In particular, SDN and NFV enable the flexible composition of network functions, a generic service concept known as network service chaining (NSC).However, the control of resources, management and configuration of network service chains is challenging. In particular, there typically exist multiple options on how an abstract network service can be decomposed into more refined, inter-connected network functions. Moreover, efficient algorithms have to be devised to allocate the network functions. The underlying algorithmic problem can be seen as a novel generalization of the Virtual Network Embedding Problem (VNEP), where there exist multiple realization options. The joint optimization of decomposition and embedding has not been studied in the literature before.This paper studies the problem of how to optimally decompose and embed network services. In particular, we propose two novel algorithms to map NSCs to the network infrastructure while allowing possible decompositions of network functions. The first algorithm is based on Integer Linear Programming (ILP) which minimizes the cost of the mapping based on the NSCs requirements and infrastructure capabilities. The second one is a heuristic algorithm to solve the scalability issue of the ILP formulation. It targets to minimize the mapping cost by making a reasonable selection of the network function decompositions. The experimental results indicate that considering network function decompositions at the time of the embedding significantly improves the embedding performance in terms of acceptance ratio while decreasing the mapping cost in the long run in both optimal and heuristic solutions.

Network service chaining with efficient network function mapping based on service decompositions

Network Service Chaining (NSC) is a service concept which promises increased flexibility and cost-efficiency for future carrier networks. The two recent developments, Network Function Virtualization (NFV) and Software-Defined Networking (SDN), are opportunities for service providers to simplify the service chaining and provisioning process and reduce the cost (in CAPEX and OPEX) while introducing new services as well. One of the challenging tasks regarding NFV-based services is to efficiently map them to the components of a physical network based on the services specifications/constraints. In this paper, we propose an efficient cost-effective algorithm to map NSCs composed of Network Functions (NF) to the network infrastructure while taking possible decompositions of NFs into account. NF decomposition refers to converting an abstract NF to more refined NFs interconnected in form of a graph with the same external interfaces as the higher-level NF. The proposed algorithm tries to minimize the cost of the mapping based on the NSCs requirements and infrastructure capabilities by making a reasonable selection of the NFs decompositions. Our experimental evaluations show that the proposed scheme increases the acceptance ratio significantly while decreasing the mapping cost in the long run, compared to schemes in which NF decompositions are selected randomly.

Towards Unified Programmability of Cloud and Carrier Infrastructure

The rise of cloud services poses considerable challenges on the control of both cloud and carrier network infrastructures. While traditional telecom network services rely on rather static processes (often involving manual steps), the wide adoption of mobile devices including tablets, smartphones and wearables introduce previously unseen dynamics in the creation, scaling and withdrawal of new services. These phenomena require optimal flexibility in the characterization of services, as well as on the control and orchestration of both carrier and cloud infrastructure. This paper proposes a unified programmability framework addressing: the unification of network and cloud resources, the integrated control and management of cloud and network, the description for programming networked/cloud services, and the provisioning processes of these services. In addition proofs-of-concept are provided based on existing open source control software components.

ESCAPE: extensible service chain prototyping environment using mininet, click, NETCONF and POX

Mininet is a great prototyping tool which combines existing SDN-related software components (e.g., Open vSwitch, OpenFlow controllers, network namespaces, cgroups) into a framework, which can automatically set up and configure customized OpenFlow testbeds scaling up to hundreds of nodes. Standing on the shoulders of Mininet, we implement a similar prototyping system called ESCAPE, which can be used to develop and test various components of the service chaining architecture. Our framework incorporates Click for implementing Virtual Network Functions (VNF), NETCONF for managing Click-based VNFs and POX for taking care of traffic steering. We also add our extensible Orchestrator module, which can accommodate mapping algorithms from abstract service descriptions to deployed and running service chains.

Multi-Domain Service Orchestration Over Networks and Clouds: A Unified Approach

End-to-end service delivery often includes transparently inserted Network Functions (NFs) in the path. Flexible service chaining will require dynamic instantiation of both NFs and traffic forwarding overlays. Virtualization techniques in compute and networking, like cloud and Software Defined Networking (SDN), promise such flexibility for service providers. However, patching together existing cloud and network control mechanisms necessarily puts one over the above, e.g., OpenDaylight under an OpenStack controller. We designed and implemented a joint cloud and network resource virtualization and programming API. In this demonstration, we show that our abstraction is capable for flexible service chaining control over any technology domains.

DevOps for network function virtualisation: an architectural approach

The Service Programming and Orchestration for Virtualised Software Networks SONATA project targets both the flexible programmability of software networks and the optimisation of their deployments by means of integrating Development and Operations in order to accelerate industry adoption of software networks and reduce time-to-market for networked services. SONATA supports network function chaining and orchestration, making service platforms modular and easier to customise to the needs of different service providers, and introduces a specialised Development and Operations model for supporting developers.

Link failure recovery technique for greedy routing in the hyperbolic plane

The scalability of current routing protocols is limited by the linearly increasing size of the corresponding routing tables. Greedy routing has been proposed as a solution to this scalability problem. In greedy routing, every node is assigned a coordinate. These coordinates are used in order to forward a packet to a neighbor which is closer to the destination. Current greedy methods cannot efficiently cope with failures in topology. Using methods which require large resources and have significant loss in the quality of the routing (stretch loss) makes greedy routing useless in large-scale networks. In this paper, local techniques for single and multiple link failure recovery are proposed. The methods require very limited resources and result into limited loss in routing quality. The proposed schemes allow fast switch-over and scale with the number of links in the spanning tree of the network. Scalability, simplicity and low overhead of the methods make them suitable for large networks. The proposed techniques are evaluated in an experimental environment.

Scalable Architecture for Service Function Chain Orchestration

Network Function Virtualization (NFV) enables to implement network functions in software, high-speed packet processing functions which traditionally are dominated by hardware implementations. Virtualized Network Functions (NFs) may be deployed on generic-purpose servers, e.g., in datacenters. The latter enables flexibility and scalability which previously were only possible for web services deployed on cloud platforms. The merit of NFV is challenged by control challenges related to the selection of NF implementations, discovery and reservation of sufficient network and server resources, and interconnecting both in a way which ful fills SLAs related to reliability and scalability. This paper details the role of a scalable orchestrator in charge of finding and reserving adequate resources. The latter will steer network and cloud control and management platforms to actually reserve and deploy requested services. We highlight the role of involved interfaces, propose elements of algorithmic components, and will identify major blocks in orchestration time in a proof of concept prototype which accounts for most functional parts in the considered architecture. Based on these evaluations, we propose several architectural enhancements in order to implement a highly scalable network orchestrator for carrier and cloud networks.

Manifesto of edge ICT fabric

Technology advances are making available huge amounts of processing, storage, networking capabilities at the edge (i.e., up to End-Users premises) of current networks. It is argued that these trends, coupled with new emerging paradigms such as Software Defined Networks, will impact deeply the evolution of future networks, allowing to design highly flexible architectures at the edge capable of creating a galaxy of new ICT business opportunities. This paper presents this vision by proposing a so-called “manifesto of Edge ICT Fabric”: the sheer number of nodes, devices and systems being deployed at the edge, up to Users premises, will create an ICT fabric offering an enormous processing and storage power. Using this Edge ICT fabric, which is closer to the Users, for executing network functions and services will bring several advantages, both in term of improved performance and cost savings (e.g., determined by the removal of middle-boxes). It is argued that incentives, cooperation and competition at the edge will boost the long-term value of networks: like in ecosystems, where evolution select the winning species, winning services will succeed, grow, and promote further investments, while losing ideas will fade away.

Deploying SDN and NFV at the speed of innovation: toward a new bond between standards development organizations, industry fora, and open-source software projects

Standards development organizations (SDOs) exist to assure the development of consensus- based, quality standards. These formal standards are needed in the telecommunications market to achieve functional interoperability. The standardization process takes years, and then a vendor still needs to implement the resulting standard in a product. This prevents service providers (SPs) who are willing to venture into new domains from doing so at a fast pace. With the development of software-defined networking (SDN) and network function virtualization (NFV), opensource technology is emerging as a new option in the telecommunications market. In contrast to SDOs, open-source software (OSS) communities create a product that may implicitly define a de-facto standard based on market consensus. Therefore, SPs are drawn to OSS, but they face technical, procedural, legal, and cultural challenges due to their lack of experience with open software development. The question therefore arises, how the interaction between OSS communities, SDOs, and industry fora (IF) can be organized to tackle these challenges.