State-aware Subscriber Steering in Fiber Access Networks for Improved Resilience

Network softwarization is currently emerging in home and enterprise Internet access networks. Still, the advantages of programmable hardware nodes and virtualized network functions in the access network as resilience enablers should be researched more. Access networks are typically built in a two-layer tree topology with sparse redundancy and limited adaptability. To overcome this, this work investigates how softwarization with redundancy can achieve resilience improvements in such networks. We present an architecture and prototypical implementation of a fiber-based access network and subscriber termination, with a redundant and adaptive design throughout the whole path from subscribers to the Internet. By proactively migrating states and steering subscriber flows, we reached total average downtimes of around 156 milliseconds to restore Internet access after disruption in the case of one subscriber. In comparison, it takes hours to restore Internet access in case of an outage with zero redundancy. Our solution is cost-effective by exploiting the architectural advances of Software Defined Networking, allowing the use of virtualized network functions and hardware-based functions simultaneously.