... is built to be carrier-class with Cisco IOSĀ® Software and hardware features. Cisco used its experience working with ... IP services while maintaining line-rate performance. PXF is software-based; customers can add new service functions without swapping ... Cisco Nonstop Forwarding (NSF), Nonstop Routing (NSR), In Service Software Upgrade (ISSU), and Automatic Protection Switching (APS). Support for MPLS ...