A Robustness-Aware Real-Time SFC Routing Update Scheme in Multi-Tenant Clouds.

In multi-tenant clouds, requests need to traverse a set of network functions (NFs) in a specific order, referred to as a service function chain (SFC), for security and business logic issues. Due to workload dynamics, the central controller of a multi-tenant cloud needs to frequently update the SFC routing, so as to optimize various network performance, such as load balancing. To achieve effective SFC routing update, we should consider two critical requirements: system robustness and real-time update. Without considering these two requirements, prior works either result in fragile clouds or suffer from large update delay. In this paper, we propose a robustness-aware real-time SFC routing update (R3-UA) scheme which takes both requirements into consideration. R3-UA pursues robustness-aware real-time routing update through two phases: robust NF instance assignment update and real-time SFC routing update. Two algorithms with bounded approximation ratios are proposed for these two phases, respectively. We implement R3-UA on a real testbed. Both small-scale experimental results and large-scale simulation results show the superior performance of R3-UA compared with other alternatives. [ABSTRACT FROM AUTHOR]