Abstract
A Click-based network function (NF) has significant advantages for pipeline development, including modularity, extensibility, and programmability. Despite these features, its internal architecture has unfortunately not kept up with some specific problems of the software upgrade. To motivate our article, we analyzed a series of use cases to identify the limitations of native Click. These limitations include the inefficiencies in modifying modules, integrating modules, and recovering states. To bridge the gap, we present three novel enhancements in our Click upgrade (Click-UP) system: 1) modular state abstraction refines each type of stateful operations as an atom operation and decouples it from the pipeline, letting separately managing logics for stateless operations and stateful operations become practical; 2) essential module integration manages dependencies between modules, avoiding shipping unnecessary modules with neutral functionalities to the target NF; and 3) local state migration migrates needed states seamlessly from the old NF to the target NF at local memory. Our evaluation demonstrates that Click-UP reduces the context code required for module modification by 12-81%, cutting down the NF integration time by 78-96% and the service disruption time by 76-93%, as compared to the software upgrade performance represented by native Click.