Achieving High Availability in Inter-DC WAN Traffic Engineering

Inter-DataCenter Wide Area Network (Inter-DC WAN) that connects geographically distributed data centers is becoming one of the most critical network infrastructures. Due to limited bandwidth and inevitable link failures, it is highly challenging to guarantee network availability for services, especially those with stringent bandwidth demands, over inter-DC WAN. We present $\mathsf {TEDAT}$ , a novel Traffic Engineering (TE) framework for Diverse Availability Targets (DAT), where a Service Level Agreement (SLA) is defined to ensure that each bandwidth demand must be satisfied with a stipulated probability, when subjected to the network capacity and possible failures of the inter-DC WAN. $\mathsf {TEDAT}$ has two core components, i.e., traffic scheduling and failure recovery, which are crystalized through different mathematical models and theoretically analyzed. They are also extensively compared against state-of-the-art TE schemes, using a testbed as well as real trace driven simulations across different topologies, traffic matrices and failure scenarios. Our evaluations show that, compared with the optimal admission strategy, $\mathsf {TEDAT}$ can speed up the online admission control by $30\times $ at the expense of less than 4% false rejections. On the other hand, compared with the latest TE schemes like FFC and TEAVAR, $\mathsf {TEDAT}$ can meet the bandwidth availability SLAs for 23%~60% more demands under normal loads, and when network failure causes SLA violations, it can retain 10%~20% more profit under a pricing and refunding model.