Enabling heterogeneous network function chaining

Today's data center operators deploy network policies in both physical (e.g., middleboxes, switches) and virtualized (e.g., virtual machines on general purpose servers) network function boxes (NFBs), which reside in different points of the network, to exploit their efficiency and agility respectively. Nevertheless, such heterogeneity has resulted in a great number of independent network nodes that can dynamically generate and implement inconsistent and conflicting network policies, making correct policy implementation a difficult problem to solve. Since these nodes have varying capabilities, services running atop are also faced with profound performance unpredictability. In this paper, we propose a Heterogeneous netwOrk Policy Enforcement (HOPE) scheme to overcome these challenges. HOPE guarantees that network functions (NFs) that implement a policy chain are optimally placed onto heterogeneous NFBs such that the network cost of the policy is minimized. We first experimentally demonstrate that the processing capacity of NFBs is the dominant performance factor. This observation is then used to formulate the Heterogeneous Network Policy Placement problem, which is shown to be NP-Hard. To solve the problem efficiently, an online algorithm is proposed. Our experimental results demonstrate that HOPE achieves the same optimality as Branch-and-bound optimization but is 3 orders of magnitude more efficient

A survey on stateful data plane in software defined networks

© 2020 Elsevier B.V. Software Defined Networking (SDN), which decouples control plane and data plane, normally stores states on controllers to provide flexible programmability and convenient management. However, recent studies have shown that such configuration may cause frequent and unnecessary interactions between data plane and controllers in some cases. For example, a DDoS detection installed on a controller needs to fetch information from data plane periodically, introducing additional network delay and controller overhead. Thus, stateful data plane is proposed to offload states and operation logics from controller to data plane. Stateful data plane allows switches to perform some operations independently, accelerating packets processing while reducing overhead on both controllers and networks. However, stateful data plane increases the complexity of network devices and imposes many new challenges to the management and schedule of SDN enabled networks. This paper conducts a comprehensive survey on the latest research works and provides insights into stateful data plane. Both stateful data plane platforms and compilers are extensively summarized and analyzed, as well as explicit design of applications based on them. Afterwards, we dwell on the fundamental technologies and research challenges, including implementation considerations of stateful data plane. Finally, we conclude this survey paper with some future works and discuss open research issues