Latency Measurement of Service Function Chaining on OpenStack Platform

Service Function Chaining allows the flexible and efficient deployment of network functions for different applications. With Network Function Virtualization the elements of the chain can be provisioned in virtual environments on any COTS hardware. This introduces the question of where to position the individual network functions within the virtualization environment. This problem of network function placement has been studied in theory as an optimization problem on a graph. However it is challenging to apply theoretical work on practical deployments. In this paper, we perform a measurement campaign to study the delay introduced by Service Function Chaining. We propose placement heuristics and evaluate the performance on OpenStack. With the proposed heuristics, the service delay can be reduced by more than 20%. We measured the overhead introduced by a network function implemented in user space. The processing delay in user space can be twice as much as the same function in kernel space. More interestingly, we identified a service interruption of more than 1 second after activation of the chain.