Resiliency Challenges in Accelerating Carrier-Grade Networks with SDN

Today's carrier-grade networks are highly resilient and provide close to 4 9s end-to-end availability for various services. Going forward it is expected that Software Defined Networking (SDN) will be deployed in carrier networks to offer dynamically programmable services with an equivalent, or even higher, expectation of service availability. Though SDN, with the separation of the control and data planes, offers flexibility and programmability it also presents significant challenges with respect to resiliency. In this position paper we present the resiliency challenges for future carrier-grade networks based on SDN. To this end, we first present an analysis of outage data for today's carrier-grade networks to identify critical failure patterns across several network devices and infer network outage impacts. We then describe an architecture to implement future carrier-grade networks leveraging cloud computing and SDN. Finally, based on our findings on today's carrier-grade networks we identify resiliency challenges for SDN based carrier-grade networks.