At the Edge? Wait no More: Immediate Placement of Time-Critical SFCs with VNF Sharing

The increasing demand on real-time and time-critical applications such as augmented reality, virtual reality, collision avoidance and industrial IoT, is fuelled by the low-latency promised by next-generation mobile networks (5G). Time-critical applications and services are real-time software whose failure could result in catastrophic consequences such as fatalities, damage to property, even financial losses. Edge computing is the main enabler of 5G ultra-low latency use cases. Edge resources are limited compared to the abundant cloud computing resources. As such, provisioning time-critical applications at the edge is more challenging and demanding. Even though virtual network function (VNF) sharing improves the utilization of the service providers’ resources, service requests -including time-critical ones- can still be rejected due to insufficient resources. This paper proposes IPTSV, an immediate placement scheme for time-critical services with VNF sharing. The proposed scheme prioritizes time-critical premium (Pr) services over best-effort (BE) services. In cases when no resources are available for Pr services, a preemption mechanism preempts resources for the Pr service, by deporting one or more deployed BE services. The experimental results show that IPTSV can reduce the Pr services rejection rate to $\sim 0\%$, while minimizing the disturbance that BE services might witness such as prolonged waiting and turnaround times.