Penerapan Dynamic Flow Removal untuk Mencegah Flow Table Overflow pada Software-Defined Networking

Software-Defined Networking (SDN) memungkinkan penerusan paket data secara terprogram dalam sebuah jaringan dengan mendefinisikan rincian flow dalam flow table setiap switch jaringan. Namun, kapasitas flow table adalah sumber daya yang terbatas, sehingga memerlukan pengelolaan yang cermat untuk hal ini. Artikel ilmiah ini membahas pengelolaan flow table dengan metode penghapusan rincian flow secara dinamis (dynamic flow removal) untuk mencegah terjadinya flow table overflow pada SDN. Dynamic flow removal yang dimaksud adalah dengan melakukan pemantauan flow expiry dan secara selektif melakukan penghapusan rincian flow yang sudah tidak lagi aktif sehingga dapat mengurangi jumlah okupansi rincian flow pada flow table. Penghapusan rincian flow secara selektif akan dipicu setiap kali kapasitas flow table hampir penuh. Implementasi dynamic flow removal dilakukan dengan studi kasus aplikasi server load-balancing berbasis round-robin pada SDN dengan framework Ryu, Mininet, dan modifikasi kapasitas flow table pada OpenvSwitch. Hasil pengujian menunjukkan bahwa penerapan metode yang diusulkan mampu mencegah terjadinya flow table overflow dengan 100% rincian flow aktif dapat menempati flow table tanpa menyebabkan kegagalan komunikasi client-server. AbstractSoftware-Defined Networking (SDN) enables programmable packet forwarding by defining flow rules in the flow table of each network switch. However, the flow table capacity is a limited resource that requires careful management. This paper discusses the implementation of dynamic flow removal in managing flow tables in an OpenFlow-based SDN switch to prevent flow table overflow. Dynamic flow removal is realized by monitoring flow expiry and selectively removing flow rules that are no longer active to reduce the number of flow rules in the flow table. Selective removal of flow rules will be triggered whenever the flow table capacity is almost full. Dynamic flow removal was implemented using a case study of a round-robin-based load-balancing server application on SDN with Ryu framework, Mininet, and a modified flow table space in OpenvSwitch. The evaluation results indicate that the proposed method can prevent flow table overflow while maintaining 100% of active flow rules in the flow table without compromising client-server communication

Flow Delegation: Flow Table Capacity Bottleneck Mitigation for Software-defined Networks

This dissertation introduces flow delegation, a novel concept to deal with flow table capacity bottlenecks in Software-defined Networks (SDNs). Such bottlenecks occur when SDN switches provide insufficient flow table capacity which can lead to performance degradation and/or network failures. Flow delegation addresses this well-known problem by automatically relocating flow rules from a bottlenecked switch to neighboring switches with spare capacity. Different from existing work, this new approach can be used on-demand in a transparent fashion, i.e., without changes to the network applications or other parts of the infrastructure. The thesis presents a system design and architecture capable of dealing with the numerous practical challenges associated with flow delegation, introduces suitable algorithms to efficiently mitigate bottlenecks taking future knowledge and multiple objectives into account and studies feasibility, performance, overhead, and scalability of the new approach covering different scenarios