Service Function Chaining (SFC) is a networking concept by which traffic is steered through a set of ordered functions composing an end-to-end service. It represents one of the facilitating technologies for 5G, and is enabled by the Network Function Virtualization (NFV) and Software Defined Networks (SDN) paradigms. In the multi-domain context, SFC placement faces new challenges related to the lack of visibility on the local domain’s networks, indeed, the domain operators are often reluctant to unveil details on their topology to external parties. Furthermore, the new 5G use cases introduce new requirements related to Quality of Service (QoS) and Quality of Experience (QoE), requirements that the placement process needs to optimize simultaneously. Another issue stems from the possible heterogeneity in encapsulation methods that are implemented by each domain, which means that an interfacing entity is needed at the ingress of each domain, to add the sub-SFCs encapsulation that is implemented by the domain. Furthermore, to ensure the end-to-end forwarding of SFC packets, each domain should be able to classify the packets at its network’s ingress, and be aware of the next domain in the global SFC.
In this thesis, multiple solutions are proposed to enable Service Function Chaining over multiple domains. First, a hierarchical framework is elaborated for SFC placement with limited visibility, and an ILP model is formulated for the optimization problem, a heuristic is also developed for scalability. Next, the formulation is improved to express the user’s preferences more accurately using Physical Programming, and SLA classes are determined according to the 5G use cases and their requirements in terms of latency and bandwidth per user. This approach is compared to the previously modeled ILP. The results show that Physical Programming allows the generation of placement solutions that are closer to the user’s preferences for all of the optimization objectives. Finally, an ETSI-compliant orchestration framework is proposed, to deploy multi-domain SFCs while taking into account the difference in encapsulations implemented by each domain. The mechanisms for the end-to-end SFC deployment and deletion are detailed, and a Proof of Concept is implemented.