Service Function Chaining (SFC) allows the forwarding of traffic flows along a chain of Virtual Network Functions (VNFs). Software Defined Networking (SDN) solutions can be used to support SFC to reduce both the management complexity and the operational costs. One of the most critical issues for the service and network providers is the reduction of energy consumption, which should be achieved without impacting the Quality of Service (QoS). In this paper, we propose a novel resource allocation architecture which enables energy-aware SFC for SDN-based networks, considering also constraints on delay, link utilization, server utilization. To this end, we formulate the problems of VNF placement, allocation of VNFs to flows, and flow routing as Integer Linear Programming (ILP) optimization problems. Since the formulated problems cannot be solved (using ILP solvers) in acceptable timescales for realistic problem dimensions, we design a set of heuristic to find near-optimal solutions in timescales suitable for practical applications. We numerically evaluate the performance of the proposed algorithms over a real-world topology under various network traffic patterns. Our results confirm that the proposed heuristic algorithms provide near-optimal solutions (at most 14% optimality-gap) while their execution time makes them usable for real-life networks.

The SRv6 architecture (segment routing based on IPv6 data plane) is a promising solution to support services like Traffic Engineering, service function chaining and virtual private networks in IPv6 backbones and datacenters. The SRv6 architecture has interesting scalability properties as it reduces the amount of state information that needs to be configured in the nodes to support the network services. In this paper, we describe the advantages of complementing the SRv6 technology with an software defined networking (SDN) based approach in backbone networks. We discuss the architecture of a SRv6 enabled network based on Linux nodes. In addition, we present the design and implementation of the Southbound API between the SDN controller and the SRv6 device. We have defined a data-model and four different implementations of the API, respectively based on gRPC, REST, NETCONF, and remote command line interface. Since it is important to support both the development and testing aspects we have realized an Intent-based emulation system to build realistic and reproducible experiments. This collection of tools automate most of the configuration aspects relieving the experimenter from a significant effort. Finally, we have realized an evaluation of some performance aspects of our architecture and of the different variants of the Southbound APIs and we have analyzed the effects of the configuration updates in the SRv6 enabled nodes.

Service Function Chaining (SFC) is a service deployment concept that promises cost efficiency and increases flexibility for computer networks. On the other hand, Software Defined Networking (SDN) provides a powerful infrastructure to implement SFC. In this paper, we mathematically formulate the SFC problem in SDN-based networks. In this way, the energy consumption of the network is minimized while the traffic congestion is controlled through network reconfiguration. Additionally, a low complex heuristic algorithm is proposed to find a near-optimal solution for the mentioned problem. Simulation results show that the proposed heuristic reconfigures the network in a way that the energy consumption is near-optimal while the SFC requirements are met. Besides, the computational complexity is very low which makes it applicable for real-world networks.