Intra-Node Resource Isolation for SFC with SR-IOV

Single Root I/O Virtualization (SR-IOV) is intended to provide simultaneous native access to network interface cards (NIC) from multiple virtual machines or applications. For this, SR-IOV offloads packet switching from software to hardware. We use SR-IOV outside its original purpose and establish a chaining infrastructure between virtual Service Functions. Thus, resources to provide chaining are isolated by the NIC. We compare Service Function Chains based on SR-IOV to fully software-based Service Function Chains and survey how shifting workload from the CPU to the NIC affects performance. Furthermore, we analyze the impact of virtual PCIe functions, which are required for the use of SR-IOV, on performance. Our study provides a detailed performance evaluation of Service Function Chains implemented with Open vSwitch and DPDK. The performance evaluation is based on comparative measurements on commodity hardware including profiling of the CPU and PCIe bus. We model the resource constraints of both implementation approaches to specify performance bottlenecks and to determine a scenario's maximum throughput.